fix(update,session): brain_update and session_log confine caller paths (#169)

Review round 1 on PR #170 found two more handlers with the #169 class of
bug (verified by execution):

- brain_update resolved its caller path with resolveWithin, a lexical
  containment check: any brain file could be superseded
  (classification.yaml, raw/, sessions/), and a final symlink was
  written through. UpdateNote now resolves like brain_edit
  (notes.Resolve, ScopeNotes: knowledge/ and wiki/ .md notes), and reads
  and rewrites through brainfs (ReadRegular, WriteRegular).
- session_log joined the caller's session_id onto the sessions dir and
  opened it O_CREATE|O_APPEND: an id with path segments created or
  appended a .jsonl file anywhere the pod could write. The id must now
  be a plain name (^[A-Za-z0-9_][A-Za-z0-9._-]{0,127}$, which every live
  session file matches), and the open adds O_NOFOLLOW|O_NONBLOCK. Read
  checks the id too.
- Tunnel tests: the .txt case now names an existing file (it failed on
  "missing" before), the symlink test adds an in-brain target, and the
  FIFO comment no longer claims the handle check is the only guard.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ingestion/cmd/server/jwt_validator.go

@@ -1,26 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"log/slog"
-
-	chassisauth "git.d-ma.be/mathias/mcp-chassis/auth"
-)
-
-// buildJWTValidator builds the JWT validator for issuer (nil when issuer is
-// empty: JWT auth disabled). Since mcp-chassis v0.7 construction no longer
-// fails when OIDC discovery does (mcp-chassis#4): the issuer resolves lazily,
-// and until it does a JWT is answered 503-and-retry, not 401. That replaces
-// #83's boot-time retry loop (hyperguild#155). An issuer still unresolved at
-// boot is logged, so a misconfigured issuer is visible rather than silent.
-func buildJWTValidator(ctx context.Context, logger *slog.Logger, issuer, audience string) (*chassisauth.JWTValidator, error) {
-	v, err := chassisauth.NewJWTValidator(ctx, issuer, audience)
-	if err != nil {
-		return nil, fmt.Errorf("build jwt validator: %w", err)
-	}
-	if ok, rerr := v.Ready(ctx); !ok {
-		logger.Warn("jwt issuer not resolved at boot; JWTs answer 503 until it is", "issuer", issuer, "err", rerr)
-	}
-	return v, nil
-}

ingestion/cmd/server/jwt_validator_test.go

@@ -1,111 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"context"
-	"io"
-	"log/slog"
-	"net/http"
-	"net/http/httptest"
-	"sync/atomic"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/metrics"
-)
-
-// fakeIssuer answers OIDC discovery with 502 for the first fail requests, as
-// ingress does while dex is not yet serving on a cold boot (#83), then with a
-// real discovery document and an empty JWKS.
-func fakeIssuer(t *testing.T, fail int32) (*httptest.Server, *atomic.Int32) {
-	t.Helper()
-	var discoveries atomic.Int32
-	mux := http.NewServeMux()
-	var srv *httptest.Server
-	mux.HandleFunc("/.well-known/openid-configuration", func(w http.ResponseWriter, _ *http.Request) {
-		if discoveries.Add(1) <= fail {
-			w.WriteHeader(http.StatusBadGateway)
-			return
-		}
-		w.Header().Set("Content-Type", "application/json")
-		_, _ = io.WriteString(w, `{"issuer":"`+srv.URL+`","jwks_uri":"`+srv.URL+`/keys"}`)
-	})
-	mux.HandleFunc("/keys", func(w http.ResponseWriter, _ *http.Request) {
-		w.Header().Set("Content-Type", "application/json")
-		_, _ = io.WriteString(w, `{"keys":[]}`)
-	})
-	srv = httptest.NewServer(mux)
-	t.Cleanup(srv.Close)
-	return srv, &discoveries
-}
-
-// #83 retried discovery at boot because chassis v0.2.0 failed construction on
-// a 502. Since chassis v0.7 (mcp-chassis#4) the validator is built anyway and
-// resolves the issuer lazily, so boot no longer waits or exits on it
-// (hyperguild#155). An unresolved issuer is logged at boot.
-func TestBuildJWTValidatorReturnsAValidatorWhileDiscovery502s(t *testing.T) {
-	srv, _ := fakeIssuer(t, 1000)
-	var buf bytes.Buffer
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.NewTextHandler(&buf, nil)), srv.URL, "brain")
-	require.NoError(t, err)
-	assert.NotNil(t, v)
-	assert.Contains(t, buf.String(), "jwt issuer not resolved at boot")
-}
-
-func TestBuildJWTValidatorLogsNothingAgainstAHealthyIssuer(t *testing.T) {
-	srv, _ := fakeIssuer(t, 0)
-	var buf bytes.Buffer
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.NewTextHandler(&buf, nil)), srv.URL, "brain")
-	require.NoError(t, err)
-	assert.NotNil(t, v)
-	assert.NotContains(t, buf.String(), "not resolved")
-}
-
-func TestBuildJWTValidatorIsNilWithoutAnIssuer(t *testing.T) {
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.DiscardHandler), "", "brain")
-	require.NoError(t, err)
-	assert.Nil(t, v)
-}
-
-// With the issuer unresolved, a JWT on a REST route answers 503 (retry), not
-// 401: the token may be fine, the server just cannot check it yet.
-func TestBuildMuxAnswers503ToAJWTWhileTheIssuerIsUnresolved(t *testing.T) {
-	srv, _ := fakeIssuer(t, 1000)
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.DiscardHandler), srv.URL, "brain")
-	require.NoError(t, err)
-	mux, err := buildMux(restAuth{token: routesTok, validator: v, realm: "brain"}, testHandler(t),
-		okHandler("mcp"), metrics.New(), nil)
-	require.NoError(t, err)
-	code, _ := do(t, mux, "GET", "/pending", "Bearer aaa.bbb.ccc")
-	assert.Equal(t, http.StatusServiceUnavailable, code)
-}
-
-// PR #183 review: /mcp shares REST's bearer, but only the static token was
-// asserted on it. With the issuer unresolved, a JWT on /mcp answers 503 too,
-// so /mcp's middleware was built with the JWT validator.
-func TestBuildMuxAnswers503ToAJWTOnMCPWhileTheIssuerIsUnresolved(t *testing.T) {
-	srv, _ := fakeIssuer(t, 1000)
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.DiscardHandler), srv.URL, "brain")
-	require.NoError(t, err)
-	mux, err := buildMux(restAuth{token: routesTok, validator: v, realm: "brain"}, testHandler(t),
-		okHandler("mcp"), metrics.New(), nil)
-	require.NoError(t, err)
-	code, _ := do(t, mux, "POST", "/mcp", "Bearer aaa.bbb.ccc")
-	assert.Equal(t, http.StatusServiceUnavailable, code)
-}
-
-// PR #183 review: a 401 on /mcp names the protected-resource metadata in
-// WWW-Authenticate (what the claude.ai OAuth connector discovers from), so
-// /mcp's middleware was built with resourceMetadataURL.
-func TestBuildMuxMCP401CarriesResourceMetadataInWWWAuthenticate(t *testing.T) {
-	const rm = "https://brain.example/.well-known/oauth-protected-resource"
-	mux, err := buildMux(restAuth{token: routesTok, realm: "brain", resourceMetadataURL: rm}, testHandler(t),
-		okHandler("mcp"), metrics.New(), nil)
-	require.NoError(t, err)
-	rec := httptest.NewRecorder()
-	mux.ServeHTTP(rec, httptest.NewRequest(http.MethodPost, "/mcp", nil))
-	require.Equal(t, http.StatusUnauthorized, rec.Code)
-	assert.Contains(t, rec.Header().Get("WWW-Authenticate"), `resource_metadata="`+rm+`"`)
-}

ingestion/cmd/server/main.go

@@ -32,6 +32,7 @@ import (
 	"github.com/mathiasbq/hyperguild/ingestion/internal/pipeline"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/reranker"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/search"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/startupretry"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/symlinkguard"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/vectorstore"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/watcher"
@@ -368,15 +369,27 @@ func main() {
 	// hyperguild#157: report a symlink that appears in the brain while running.
 	go symlinkguard.Watch(ctx, brainDir, symlinkScanInterval(os.Getenv), buildNotifier())
 
-	// Never fatal on an unreachable issuer (#83): on a cold cluster boot this
+	// Built before the watcher, the graph backfill and session ingestion, and
-	// pod can beat dex to serving and get a 502 from ingress, and exiting meant
+	// retried rather than fatal (#83). Two separate reasons:
-	// CrashLoopBackOff redoing the backfill. Since mcp-chassis v0.7 the
+	//
-	// validator resolves the issuer lazily and answers JWTs 503-and-retry until
+	//   - On a cold cluster boot this pod can beat dex to serving and gets a
-	// it does (hyperguild#155), so no boot retry is needed. A misconfigured
+	//     502 from ingress. Nothing is misconfigured; it simply started first.
-	// issuer no longer exits the process: it is logged at boot and every JWT
+	//     Exiting there meant CrashLoopBackOff redoing the backfill on every
-	// gets 503; the static bearer keeps working.
+	//     attempt, with exponential backoff stretching the brain outage.
-	jwtValidator, err := buildJWTValidator(ctx, logger,
+	//   - Constructing it first means a genuine config error (wrong issuer,
-		os.Getenv("DEX_ISSUER_URL"), os.Getenv("MCP_AUDIENCE"))
+	//     bad audience) fails in seconds instead of after all that work.
+	//
+	// The budget stays bounded: retrying forever would turn a misconfiguration
+	// into a process that looks alive and never serves.
+	jwtValidator, err := startupretry.Do(ctx,
+		startupretry.Policy{Attempts: 8, Base: time.Second, Max: 30 * time.Second},
+		func(ctx context.Context) (*chassisauth.JWTValidator, error) {
+			v, err := chassisauth.NewJWTValidator(ctx, os.Getenv("DEX_ISSUER_URL"), os.Getenv("MCP_AUDIENCE"))
+			if err != nil {
+				logger.Warn("oidc discovery not ready, retrying", "err", err)
+			}
+			return v, err
+		})
 	if err != nil {
 		logger.Error("build jwt validator", "err", err)
 		os.Exit(1)
@@ -516,6 +529,8 @@ func main() {
 		}
 	}
 
+	public["/mcp"] = chassisauth.BearerMiddleware(mcpToken, jwtValidator, "brain", resourceMetadataURL, mcpSrv)
+
 	// POST /capture (#53/#54): the uniform capture REST door. Needs a ticket
 	// tracker to file action items, so it only mounts when Gitea is
 	// configured. It reuses the MCP server's graph-wired brain store (one
@@ -539,7 +554,7 @@ func main() {
 		public["POST /capture"] = captureH
 		// Same use-case behind the MCP `capture` tool (#55 relay) so MCP-native
 		// harnesses (claude.ai, Crush, Pi, LLM Council) reach capture through
-		// the existing /mcp OAuth connector. buildMux wraps this same mcpSrv;
+		// the existing /mcp OAuth connector. mcpSrv is already wrapped above;
 		// WithCapture mutates the same instance, so the tool appears live.
 		mcpSrv.WithCapture(captureSvc, jwtValidator, mcpToken, "local-cli", resolver)
 		// hyperguild#97: a governance-file rewrite gets the same trail a
@@ -581,18 +596,19 @@ func main() {
 		os.Exit(1)
 	}
 
-	// /metrics — unauthenticated Prometheus endpoint, scraped via the
+	// /metrics — unauthenticated Prometheus endpoint. kube-prometheus-stack
-	// ServiceMonitor in k3s/apps/supervisor/. buildMux registers it and wraps
+	// scrapes it via the ServiceMonitor in k3s/apps/supervisor/. The metrics
-	// the whole router in the registry's middleware.
+	// middleware below wraps every other registered handler so it observes
-	//
+	// real request latency. /metrics itself is excluded from its own
-	// The whole router, /mcp's bearer included, is built in buildMux so its
+	// observation by registering it on the outer mux (post-wrap).
-	// tests are tests of production wiring (PR #152 review, hyperguild#154).
+	reg := metrics.New()
-	// The REST API's credential is the same as /mcp's. Untested here: the
+	public["GET /metrics"] = http.HandlerFunc(reg.Handler())
-	// restAuth fields and the public map this call passes in (e.g. a nil
+
-	// validator would drop JWT auth on /mcp and REST and the suite stays
+	// The whole router, built in one place so the test of buildMux is a test
-	// green), and ListenAndServe serving the result unchanged (hyperguild#182).
+	// of production wiring (PR #152 review). The REST API's credential is the
-	handler, err := buildMux(restAuth{token: mcpToken, validator: jwtValidator, realm: "brain",
+	// same as /mcp's.
-		resourceMetadataURL: resourceMetadataURL}, h, mcpSrv, metrics.New(), public)
+	mux, err := buildMux(restAuth{token: mcpToken, validator: jwtValidator, realm: "brain",
+		resourceMetadataURL: resourceMetadataURL}, h, public)
 	if err != nil {
 		logger.Error("build router", "err", err)
 		os.Exit(1)
@@ -613,7 +629,7 @@ func main() {
 		"watch_interval", watchIntervalLog,
 		"mcp_enabled", true,
 	)
-	if err := http.ListenAndServe(addr, handler); err != nil {
+	if err := http.ListenAndServe(addr, reg.Middleware(mux)); err != nil {
 		logger.Error("server stopped", "err", err)
 		os.Exit(1)
 	}

ingestion/cmd/server/routes.go

@@ -8,22 +8,22 @@ import (
 	chassisauth "git.d-ma.be/mathias/mcp-chassis/auth"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/metrics"
 )
 
-// publicRoutes is the complete set of patterns a caller may register on the
+// publicRoutes is the complete set of patterns allowed on the outer mux,
-// outer mux, outside the REST API's auth (hyperguild#149). Each authenticates
+// outside the REST API's auth (hyperguild#149). Each authenticates itself or is
-// itself or is meant to be open: /capture (bearer/JWT), the webhook (HMAC),
+// meant to be open: /mcp (bearer/JWT), /capture (bearer/JWT), the webhook
-// /oauth/token (client secret) and OAuth metadata (open). /mcp and /metrics
+// (HMAC), /oauth/token (client secret), OAuth metadata and /metrics (open).
-// are not here: buildMux builds them itself (hyperguild#154). A REST pattern
+// A REST pattern added here would beat the authenticated catch-all by
-// added here would beat the authenticated catch-all by specificity and ship
+// specificity and ship open, which is why buildMux refuses anything else.
-// open, which is why buildMux refuses anything else.
 var publicRoutes = map[string]bool{
+	"/mcp":                      true,
 	"POST /capture":             true,
 	"POST /webhooks/brain-sync": true,
 	"GET /.well-known/oauth-protected-resource":   true,
 	"GET /.well-known/oauth-authorization-server": true,
 	"POST /oauth/token":                           true,
+	"GET /metrics":                                true,
 }
 
 // restAuth is the credential the REST API checks: the same as /mcp's.
@@ -34,25 +34,16 @@ type restAuth struct {
 	resourceMetadataURL string
 }
 
-// buildMux builds the handler main passes to ListenAndServe unchanged. The
+// buildMux is the server's whole router. The REST API is mounted at "/"
-// REST API is mounted at "/" and /mcp is registered, both behind bearer auth
+// behind bearer auth that buildMux constructs itself, so a caller cannot pass
-// that buildMux constructs itself from auth (one credential), so a caller
+// a no-op; public handlers are registered as given, and only for patterns on
-// cannot pass a no-op. GET /metrics serves reg, and the whole router is
+// the publicRoutes allowlist. It returns an http.Handler, not the
-// wrapped in reg's middleware. Other public handlers are registered as given,
+// *ServeMux, so nothing can register a route on the result afterwards and
-// and only for patterns on the publicRoutes allowlist. It returns an
+// bypass the allowlist.
-// http.Handler, not the *ServeMux, so nothing can register a route on the
+func buildMux(auth restAuth, h *api.Handler, public map[string]http.Handler) (http.Handler, error) {
-// result. What stays untested is main's call site: the restAuth fields and
-// the public map main passes in, and ListenAndServe serving this handler
-// unchanged (hyperguild#182). The tests build their own arguments.
-func buildMux(
-	auth restAuth, h *api.Handler, mcpHandler http.Handler, reg *metrics.Registry, public map[string]http.Handler,
-) (http.Handler, error) {
 	if auth.token == "" {
 		return nil, errors.New("buildMux: REST auth needs a token")
 	}
-	if mcpHandler == nil || reg == nil {
-		return nil, errors.New("buildMux: needs the MCP handler and the metrics registry")
-	}
 	mux := http.NewServeMux()
 	for pattern, handler := range public {
 		if !publicRoutes[pattern] {
@@ -60,15 +51,10 @@ func buildMux(
 		}
 		mux.Handle(pattern, handler)
 	}
-	bearer := func(next http.Handler) http.Handler {
+	mountREST(mux, h, func(next http.Handler) http.Handler {
 		return chassisauth.BearerMiddleware(auth.token, auth.validator, auth.realm, auth.resourceMetadataURL, next)
-	}
+	})
-	mux.Handle("/mcp", bearer(mcpHandler))
+	return mux, nil
-	// /metrics is registered on the mux and so observed by its own
-	// middleware, like any route.
-	mux.Handle("GET /metrics", reg.Handler())
-	mountREST(mux, h, bearer)
-	return reg.Middleware(mux), nil
 }
 
 // mountREST registers the REST API on its own mux and mounts it at "/" behind
@@ -87,23 +73,5 @@ func mountREST(mux *http.ServeMux, h *api.Handler, auth func(http.Handler) http.
 	rest.HandleFunc("POST /promote", h.Promote)
 	rest.HandleFunc("POST /backfill-embeddings", h.BackfillEmbeddings)
 	rest.HandleFunc("GET /pass-rate", h.PassRate)
-	mux.Handle("/", labelRESTPattern(rest, auth(rest)))
+	mux.Handle("/", auth(rest))
-}
-
-// labelRESTPattern sets the request's Pattern to the REST route it addresses
-// before auth runs, so the metrics middleware (which reads Pattern from the
-// same *http.Request) labels a refused request by its route rather than by
-// the "/" mount (hyperguild#155). A refused request to a path no route
-// matches keeps "/", so for refused requests the label set stays bounded by
-// the registered routes. That bound does not hold for authenticated
-// requests: an unregistered path reaches the REST mux, which 404s with an
-// empty Pattern, and the metrics middleware falls back to the raw URL path
-// (hyperguild#185).
-func labelRESTPattern(rest *http.ServeMux, next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if _, pattern := rest.Handler(r); pattern != "" {
-			r.Pattern = pattern
-		}
-		next.ServeHTTP(w, r)
-	})
 }

ingestion/cmd/server/routes_observability_test.go

@@ -1,88 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"log/slog"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// wrongTokSentinel is a presented credential distinctive enough that any
-// occurrence in a log line is the raw token, not a coincidence.
-const wrongTokSentinel = "wrong-tok-sentinel-q7zx"
-
-// hyperguild#155: since #149 every REST route sits behind BearerMiddleware,
-// and chassis v0.2.0 refused without logging, so an unknown caller got
-// silent 401s. The chassis now writes an `mcp auth rejected` line, and the
-// presented token appears nowhere in the log as a bare value (PR #181
-// review: asserting on the "Bearer " header form could never fail, since
-// the chassis logs fields, not headers).
-func TestBuildMuxRejectionLogLineOmitsTheBarePresentedToken(t *testing.T) {
-	var buf bytes.Buffer
-	prev := slog.Default()
-	slog.SetDefault(slog.New(slog.NewTextHandler(&buf, nil)))
-	t.Cleanup(func() { slog.SetDefault(prev) })
-
-	code, _ := do(t, testMux(t), "POST", "/query", "Bearer "+wrongTokSentinel)
-	require.Equal(t, http.StatusUnauthorized, code)
-	assert.Contains(t, buf.String(), "mcp auth rejected")
-	assert.Contains(t, buf.String(), "path=/query")
-	assert.NotContains(t, buf.String(), wrongTokSentinel, "the rejected token is logged as a bare value")
-	assert.NotContains(t, buf.String(), routesTok, "the valid static token is logged")
-}
-
-// The `mcp auth accepted` line leaves out the valid static token.
-func TestBuildMuxAcceptedLogLineOmitsTheBareStaticToken(t *testing.T) {
-	var buf bytes.Buffer
-	prev := slog.Default()
-	slog.SetDefault(slog.New(slog.NewTextHandler(&buf, nil)))
-	t.Cleanup(func() { slog.SetDefault(prev) })
-
-	code, _ := do(t, testMux(t), "GET", "/pending", "Bearer "+routesTok)
-	require.Equal(t, http.StatusOK, code)
-	assert.Contains(t, buf.String(), "mcp auth accepted")
-	assert.NotContains(t, buf.String(), routesTok, "the accepted static token is logged as a bare value")
-}
-
-// An authenticated REST request is labelled with the REST mux's pattern:
-// the inner mux sets it on the same *http.Request the outer middleware reads.
-func TestMetricsLabelAnAuthenticatedRESTRequestWithItsRoutePattern(t *testing.T) {
-	mux, reg := testMuxAndRegistry(t)
-	code, _ := do(t, mux, "GET", "/pending", "Bearer "+routesTok)
-	require.Equal(t, http.StatusOK, code)
-
-	rec := httptest.NewRecorder()
-	reg.Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
-	assert.Contains(t, rec.Body.String(), `path="GET /pending"`)
-	assert.NotContains(t, rec.Body.String(), `path="/"`)
-}
-
-// hyperguild#155: a request refused by REST auth never reaches the REST mux,
-// so it was labelled path="/" and a 4xx on /query could not be told from one
-// on /write. It is now labelled with the REST pattern it was addressed to.
-func TestMetricsLabelARejectedRESTRequestWithItsRoutePattern(t *testing.T) {
-	mux, reg := testMuxAndRegistry(t)
-	code, _ := do(t, mux, "POST", "/query", "")
-	require.Equal(t, http.StatusUnauthorized, code)
-
-	rec := httptest.NewRecorder()
-	reg.Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
-	assert.Contains(t, rec.Body.String(), `path="POST /query",status="4xx"`)
-}
-
-// A path no REST route matches keeps the catch-all label, so an attacker
-// probing random URLs cannot grow the series set.
-func TestMetricsLabelARejectedUnknownPathWithTheCatchAll(t *testing.T) {
-	mux, reg := testMuxAndRegistry(t)
-	code, _ := do(t, mux, "POST", "/no-such-route-zq", "")
-	require.Equal(t, http.StatusUnauthorized, code)
-
-	rec := httptest.NewRecorder()
-	reg.Handler().ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
-	assert.Contains(t, rec.Body.String(), `path="/",status="4xx"`)
-	assert.NotContains(t, rec.Body.String(), "no-such-route-zq")
-}

ingestion/cmd/server/routes_test.go

@@ -12,7 +12,6 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/metrics"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/pipeline"
 )
 
@@ -22,34 +21,20 @@ func okHandler(body string) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) { _, _ = w.Write([]byte(body)) })
 }
 
-// testMux builds the router through buildMux, the function main calls, with
+// testMux builds the router exactly as main does: buildMux with the full
-// every allowlisted public pattern (stub handlers), a stub MCP server and a
+// public set main registers (stub handlers) and real bearer config.
-// static token only: no JWT validator and no resourceMetadataURL (the tests
+// hyperguild#149: the REST API is authenticated as a whole; the PR #152
-// in jwt_validator_test.go pass those). It does not use main's own restAuth
+// review showed a test of a COPY of the router let main.go regress unseen.
-// or public map (hyperguild#182). hyperguild#149: the REST API is
-// authenticated as a whole; the PR #152 review showed a test of a COPY of
-// the router let main.go regress unseen.
 func testMux(t *testing.T) http.Handler {
 	t.Helper()
-	mux, _ := testMuxAndRegistry(t)
+	h := api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
-	return mux
-}
-
-func testMuxAndRegistry(t *testing.T) (http.Handler, *metrics.Registry) {
-	t.Helper()
 	public := map[string]http.Handler{}
 	for p := range publicRoutes {
 		public[p] = okHandler("public " + p)
 	}
-	reg := metrics.New()
+	mux, err := buildMux(restAuth{token: routesTok, realm: "brain"}, h, public)
-	mux, err := buildMux(restAuth{token: routesTok, realm: "brain"}, testHandler(t), okHandler("mcp"), reg, public)
 	require.NoError(t, err)
-	return mux, reg
+	return mux
-}
-
-func testHandler(t *testing.T) *api.Handler {
-	t.Helper()
-	return api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
 }
 
 func do(t *testing.T, h http.Handler, method, path, authz string) (int, string) {
@@ -89,9 +74,8 @@ func TestBuildMuxAuthenticatesAnUnregisteredPath(t *testing.T) {
 }
 
 // buildMux registers public handlers as given, without adding auth: each
-// public route owns its own (bearer/JWT on /capture, HMAC on the webhook,
+// public route owns its own (bearer on /mcp, HMAC on the webhook, client
-// client secret on /oauth/token) or is meant to be open (OAuth metadata).
+// secret on /oauth/token) or is meant to be open (/metrics, OAuth metadata).
-// /mcp and /metrics are not public routes: buildMux builds them itself.
 func TestBuildMuxDoesNotWrapPublicRoutes(t *testing.T) {
 	r := testMux(t)
 	for p := range publicRoutes {
@@ -109,53 +93,14 @@ func TestBuildMuxDoesNotWrapPublicRoutes(t *testing.T) {
 // over the authenticated catch-all (more specific pattern), so it is refused.
 func TestBuildMuxRefusesAPublicPatternOffTheAllowlist(t *testing.T) {
 	h := api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
-	// "/mcp" and "GET /metrics" are built by buildMux itself (hyperguild#154):
+	for _, p := range []string{"POST /query", "GET /pending", "/", "POST /metrics"} {
-	// passing either as public would register them unauthenticated or twice.
+		_, err := buildMux(restAuth{token: routesTok, realm: "brain"}, h, map[string]http.Handler{p: okHandler("x")})
-	for _, p := range []string{"POST /query", "GET /pending", "/", "POST /metrics", "/mcp", "GET /metrics"} {
-		_, err := buildMux(restAuth{token: routesTok, realm: "brain"}, h, okHandler("mcp"), metrics.New(),
-			map[string]http.Handler{p: okHandler("x")})
 		assert.Error(t, err, "public pattern %q must be refused", p)
 	}
 }
 
 func TestBuildMuxRefusesAnEmptyToken(t *testing.T) {
 	h := api.NewHandler(t.TempDir(), slog.New(slog.NewTextHandler(os.Stderr, nil)), pipeline.Config{})
-	_, err := buildMux(restAuth{token: "", realm: "brain"}, h, okHandler("mcp"), metrics.New(), nil)
+	_, err := buildMux(restAuth{token: "", realm: "brain"}, h, nil)
 	assert.Error(t, err)
 }
-
-// hyperguild#154: /mcp's bearer was built in main.go, untested; the buildMux
-// tests used stubs. buildMux now wraps the MCP handler itself, with the same
-// credential as the REST API.
-func TestBuildMuxRefusesMCPWithoutAValidToken(t *testing.T) {
-	r := testMux(t)
-	for _, authz := range []string{"", "Bearer wrong"} {
-		code, body := do(t, r, "POST", "/mcp", authz)
-		assert.Equal(t, http.StatusUnauthorized, code, "authz %q", authz)
-		assert.NotEqual(t, "mcp", body)
-	}
-	code, body := do(t, r, "POST", "/mcp", "Bearer "+routesTok)
-	assert.Equal(t, http.StatusOK, code)
-	assert.Equal(t, "mcp", body)
-}
-
-func TestBuildMuxRefusesANilMCPHandlerOrRegistry(t *testing.T) {
-	auth := restAuth{token: routesTok, realm: "brain"}
-	_, err := buildMux(auth, testHandler(t), nil, metrics.New(), nil)
-	assert.Error(t, err)
-	_, err = buildMux(auth, testHandler(t), okHandler("mcp"), nil, nil)
-	assert.Error(t, err)
-}
-
-// hyperguild#154: main wrapped buildMux's result in the metrics middleware
-// before ListenAndServe, untested. buildMux now returns the handler main
-// serves as-is, metrics included: a request through it is observed and
-// exposed on its own GET /metrics.
-func TestBuildMuxObservesRequestsAndServesMetrics(t *testing.T) {
-	r := testMux(t)
-	code, _ := do(t, r, "GET", "/pending", "Bearer "+routesTok)
-	require.Equal(t, http.StatusOK, code)
-	code, body := do(t, r, "GET", "/metrics", "")
-	require.Equal(t, http.StatusOK, code)
-	assert.Contains(t, body, `path="GET /pending"`)
-}

ingestion/go.mod

@@ -34,9 +34,9 @@ require (
 	github.com/rogpeppe/go-internal v1.15.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
-	golang.org/x/net v0.55.0 // indirect
+	golang.org/x/net v0.26.0 // indirect
 	golang.org/x/oauth2 v0.21.0 // indirect
-	golang.org/x/term v0.43.0 // indirect
+	golang.org/x/term v0.28.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.12.0 // indirect
@@ -51,7 +51,7 @@ require (
 )
 
 require (
-	git.d-ma.be/mathias/mcp-chassis v0.7.1
+	git.d-ma.be/mathias/mcp-chassis v0.2.0
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.4.0 // indirect
 	github.com/goccy/go-json v0.10.3 // indirect
@@ -66,9 +66,9 @@ require (
 	github.com/lestrrat-go/option v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/segmentio/asm v1.2.0 // indirect
-	golang.org/x/crypto v0.51.0 // indirect
+	golang.org/x/crypto v0.32.0 // indirect
-	golang.org/x/sync v0.21.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
-	golang.org/x/sys v0.45.0
+	golang.org/x/sys v0.31.0 // indirect
-	golang.org/x/text v0.39.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1
 )

ingestion/go.sum

@@ -1,5 +1,5 @@
-git.d-ma.be/mathias/mcp-chassis v0.7.1 h1:4h8TOBHTA0L/no4IPcr4tLcQtmKUlhE2/cXyPdNFGmM=
+git.d-ma.be/mathias/mcp-chassis v0.2.0 h1:6fLmb7xqRa2nNVWsHaUbbfbArgDXJw/gDhb09clBIjo=
-git.d-ma.be/mathias/mcp-chassis v0.7.1/go.mod h1:Ks7EK2UnGAN0H3rJjKUxUagX8/ZBdtLrOlcUbv0RwH8=
+git.d-ma.be/mathias/mcp-chassis v0.2.0/go.mod h1:Ks7EK2UnGAN0H3rJjKUxUagX8/ZBdtLrOlcUbv0RwH8=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -117,42 +117,42 @@ github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9dec
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.51.0 h1:IBPXwPfKxY7cWQZ38ZCIRPI50YLeevDLlLnyC5wRGTI=
+golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
-golang.org/x/crypto v0.51.0/go.mod h1:8AdwkbraGNABw2kOX6YFPs3WM22XqI4EXEd8g+x7Oc8=
+golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.55.0 h1:bcvxaJn3e1U6InsFWt1JUq1aSjnRxLzT2rtD2KfkDF8=
+golang.org/x/net v0.26.0 h1:soB7SVo0PWrY4vPW/+ay0jKDNScG2X9wFeYlXIvJsOQ=
-golang.org/x/net v0.55.0/go.mod h1:L5U2KuzuOe1lY7Z+aWVIKK6qEeJXnXV9yzGA+WCHJww=
+golang.org/x/net v0.26.0/go.mod h1:5YKkiSynbBIh3p6iOc/vibscux0x38BZDkn8sCUPxHE=
 golang.org/x/oauth2 v0.21.0 h1:tsimM75w1tF/uws5rbeHzIWxEqElMehnc+iW793zsZs=
 golang.org/x/oauth2 v0.21.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
+golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.45.0 h1:dO4czNzziLiiXplLQgBCEpCvXQ3dnkn0SdaZSYdQ+FY=
+golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
-golang.org/x/sys v0.45.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/term v0.43.0 h1:S4RLU2sB31O/NCl+zFN9Aru9A/Cq2aqKpTZJ6B+DwT4=
+golang.org/x/term v0.28.0 h1:/Ts8HFuMR2E6IP/jlo7QVLZHggjKQbhu/7H0LJFr3Gg=
-golang.org/x/term v0.43.0/go.mod h1:lrhlHNdQJHO+1qVYiHfFKVuVioJIheAc3fBSMFYEIsk=
+golang.org/x/term v0.28.0/go.mod h1:Sw/lC2IAUZ92udQNf3WodGtn4k/XoLyZoh8v/8uiwek=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.39.0 h1:UbZz4pLOvn600D6Oh6GGEI6VAmndrEBLv8/6BEXzyus=
+golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
-golang.org/x/text v0.39.0/go.mod h1:3UwRclnC2g0TU9x8PZiyfOajCd1zaUNHF9cvqcQZ+ZM=
+golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
 golang.org/x/time v0.3.0 h1:rg5rLMjNzMS1RkNLzCG38eapWhnYLFYXDXj2gOlr8j4=
 golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
-golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
+golang.org/x/tools v0.36.0 h1:kWS0uv/zsvHEle1LbV5LE8QujrxB3wfQyxHfhOk0Qkg=
-golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
+golang.org/x/tools v0.36.0/go.mod h1:WBDiHKJK8YgLHlcQPYQzNCkUxUypCaa5ZegCVutKm+s=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

ingestion/internal/api/handler.go

@@ -12,7 +12,6 @@ import (
 	"time"
 
 	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/claim"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/pipeline"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/search"
@@ -228,22 +227,14 @@ func writeHallNote(brainDir string, opts WriteNoteOptions) (string, error) {
 	// The directory is created only once the note is known to be writable:
 	// a refused write leaves nothing behind, not even an empty hall dir
 	// (brain#21; provenance refusal joins the envelope refusal here).
-	// Created through the brain root, never through a symlinked wing or
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-	// hall directory (hyperguild#188).
+		return "", fmt.Errorf("create hall dir: %w", err)
-	rel, err := filepath.Rel(brainDir, dest)
-	if err != nil {
-		return "", fmt.Errorf("note path: %w", err)
 	}
-	rel = filepath.ToSlash(rel)
+	if err := os.WriteFile(dest, []byte(final), 0o644); err != nil {
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return "", fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	if err := bfs.PutRegular(rel, []byte(final)); err != nil {
 		return "", fmt.Errorf("write: %w", err)
 	}
-	return rel, nil
+	rel, _ := filepath.Rel(brainDir, dest)
+	return filepath.ToSlash(rel), nil
 }
 
 // scalarValues flattens frontmatter fields to key -> scalar value for

ingestion/internal/api/promote.go

@@ -127,18 +127,18 @@ func PromoteNote(brainDir string, opts PromoteOptions) (string, error) {
 	}
 	fm.set("promoted_at", now)
 
-	// Write-then-delete: the source survives any write failure. Both go
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-	// through the brain root (hyperguild#188).
+		return "", fmt.Errorf("create wing dir: %w", err)
+	}
+	// Write-then-delete: the source survives any write failure.
 	promoted, err := StampProvenance(fm.render()+body, opts.Origin, opts.WrittenBy)
 	if err != nil {
 		return "", err
 	}
-	// Created with O_EXCL: a note that appeared after the collision check
+	if err := os.WriteFile(dest, []byte(promoted), 0o644); err != nil {
-	// above is never overwritten.
-	if err := createBrainFile(brainDir, dest, []byte(promoted)); err != nil {
 		return "", fmt.Errorf("write promoted note: %w", err)
 	}
-	if err := removeBrainFile(brainDir, src); err != nil {
+	if err := os.Remove(src); err != nil {
 		return "", fmt.Errorf("promoted note written but source removal failed: %w", err)
 	}
 
@@ -196,12 +196,14 @@ func RejectNote(brainDir string, opts RejectOptions) (string, error) {
 		fm.set("reject_reason", opts.Reason)
 	}
 
-	// Write-then-delete: the source survives any write failure. Both go
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
-	// through the brain root (hyperguild#188).
+		return "", fmt.Errorf("create rejected dir: %w", err)
-	if err := createBrainFile(brainDir, dest, []byte(fm.render()+body)); err != nil {
+	}
+	// Write-then-delete: the source survives any write failure.
+	if err := os.WriteFile(dest, []byte(fm.render()+body), 0o644); err != nil {
 		return "", fmt.Errorf("write rejected note: %w", err)
 	}
-	if err := removeBrainFile(brainDir, src); err != nil {
+	if err := os.Remove(src); err != nil {
 		return "", fmt.Errorf("rejected note written but source removal failed: %w", err)
 	}
 

ingestion/internal/api/promote_redirect_test.go

@@ -1,87 +0,0 @@
-package api_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-)
-
-// hyperguild#188: promote and reject wrote the destination with
-// os.MkdirAll + os.WriteFile by path, so a symlinked wing (promote) or a
-// symlinked raw/rejected (reject) redirected the note; the raw source was
-// then removed.
-func TestPromoteAndRejectRefuseASymlinkedDestinationDirectory(t *testing.T) {
-	brain := t.TempDir()
-	outside := t.TempDir()
-	raw := filepath.Join(brain, "raw")
-	require.NoError(t, os.MkdirAll(raw, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-10-05-n.md"), []byte("---\ntitle: n\n---\nbody\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(outside, filepath.Join(brain, "wiki", "lw")))
-	require.NoError(t, os.Symlink(outside, filepath.Join(raw, "rejected")))
-
-	_, err := api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "lw", Hall: "facts"})
-	assert.Error(t, err)
-	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
-	assert.Error(t, err)
-	ents, _ := os.ReadDir(outside)
-	assert.Empty(t, ents, "a note was written outside the brain")
-	_, err = os.Stat(filepath.Join(raw, "2026-10-05-n.md"))
-	assert.NoError(t, err, "the raw source is kept when the write is refused")
-
-	require.NoError(t, os.Remove(filepath.Join(raw, "rejected")))
-	_, err = api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "w", Hall: "facts"})
-	require.NoError(t, err, "positive control: promote into a real wing")
-}
-
-// StampProvenanceFile read and rewrote the note by path (provenance.ApplyFile).
-func TestStampProvenanceFileRefusesANoteBehindASymlinkedDirectory(t *testing.T) {
-	brain := t.TempDir()
-	victim := filepath.Join(brain, "raw", "facts", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("---\ntitle: v\n---\nuntouched\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(brain, "wiki", "w", "alias")))
-	assert.Error(t, api.StampProvenanceFile(brain, "wiki/w/alias/v.md", "static", "x"))
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "---\ntitle: v\n---\nuntouched\n", string(got))
-
-	real := filepath.Join(brain, "wiki", "w", "facts", "r.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
-	require.NoError(t, os.WriteFile(real, []byte("---\ntitle: r\n---\nbody\n"), 0o644))
-	require.NoError(t, api.StampProvenanceFile(brain, "wiki/w/facts/r.md", "static", "x"), "positive control")
-	got, _ = os.ReadFile(real)
-	assert.Contains(t, string(got), "written_by: x")
-}
-
-// The same through an in-brain symlinked wing and raw/rejected, which
-// os.Root alone would follow.
-func TestPromoteAndRejectRefuseAnInBrainSymlinkedDestinationDirectory(t *testing.T) {
-	brain := t.TempDir()
-	raw := filepath.Join(brain, "raw")
-	require.NoError(t, os.MkdirAll(raw, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(raw, "2026-10-05-n.md"), []byte("---\ntitle: n\n---\nbody\n"), 0o644))
-	target := filepath.Join(brain, "archive")
-	require.NoError(t, os.MkdirAll(target, 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "archive"), filepath.Join(brain, "wiki", "lw")))
-	require.NoError(t, os.Symlink(filepath.Join("..", "archive"), filepath.Join(raw, "rejected")))
-
-	_, err := api.PromoteNote(brain, api.PromoteOptions{Filename: "2026-10-05-n.md", Wing: "lw", Hall: "facts"})
-	assert.Error(t, err)
-	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
-	assert.Error(t, err)
-	ents, _ := os.ReadDir(target)
-	assert.Empty(t, ents, "a note was written at the in-brain link's target")
-	_, err = os.Stat(filepath.Join(raw, "2026-10-05-n.md"))
-	assert.NoError(t, err, "the raw source is kept")
-
-	require.NoError(t, os.Remove(filepath.Join(raw, "rejected")))
-	_, err = api.RejectNote(brain, api.RejectOptions{Filename: "2026-10-05-n.md"})
-	require.NoError(t, err, "positive control: reject into a real raw/rejected")
-}

ingestion/internal/api/provenance.go

@@ -1,10 +1,6 @@
 package api
 
 import (
-	"fmt"
-	"path/filepath"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/provenance"
 )
 
@@ -15,61 +11,11 @@ func StampProvenance(content, origin, writtenBy string) (string, error) {
 	return provenance.Apply(content, provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
 }
 
-// StampProvenanceFile applies StampProvenance to a brain-relative note path,
+// StampProvenanceFile applies StampProvenance to a brain-relative note path.
-// read and rewritten through the brain root (hyperguild#158).
 func StampProvenanceFile(brainDir, relPath, origin, writtenBy string) error {
-	rel, _, err := resolveWithin(brainDir, relPath)
+	_, abs, err := resolveWithin(brainDir, relPath)
 	if err != nil {
 		return err
 	}
-	bfs, err := brainfs.Open(brainDir)
+	return provenance.ApplyFile(abs, provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	b, err := bfs.ReadRegular(rel)
-	if err != nil {
-		return fmt.Errorf("read for provenance: %w", err)
-	}
-	out, err := provenance.Apply(string(b), provenance.Stamp{Origin: origin, WrittenBy: writtenBy})
-	if err != nil {
-		return err
-	}
-	if out == string(b) {
-		return nil
-	}
-	if err := bfs.WriteRegular(rel, []byte(out)); err != nil {
-		return fmt.Errorf("write provenance: %w", err)
-	}
-	return nil
-}
-
-// createBrainFile creates the file at abs (inside brainDir) through the
-// brain root and fails if anything is already there.
-func createBrainFile(brainDir, abs string, data []byte) error {
-	rel, err := filepath.Rel(brainDir, abs)
-	if err != nil {
-		return err
-	}
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	return bfs.CreateRegular(filepath.ToSlash(rel), data)
-}
-
-// removeBrainFile removes the file at abs (inside brainDir) through the
-// brain root.
-func removeBrainFile(brainDir, abs string) error {
-	rel, err := filepath.Rel(brainDir, abs)
-	if err != nil {
-		return err
-	}
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	return bfs.Remove(filepath.ToSlash(rel))
 }

ingestion/internal/api/readnote_root_test.go

@@ -23,13 +23,6 @@ func TestReadNoteRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
 	_, body, _, err := api.ReadNote(brain, "wiki/w/facts/leak.md")
 	assert.Error(t, err)
 	assert.NotContains(t, body, brainfstest.Sentinel)
-	// A link to a file elsewhere in the brain: os.Root allows it, only the
-	// regular-file check refuses it (hyperguild#171).
-	brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	_, body, _, err = api.ReadNote(brain, "wiki/w/facts/inlink.md")
-	assert.Error(t, err)
-	assert.NotContains(t, body, brainfstest.Sentinel)
 
 	p := filepath.Join(facts, "r.md")
 	require.NoError(t, os.WriteFile(p, []byte("---\nx: y\n---\ninside"), 0o644))
@@ -46,7 +39,5 @@ func TestReadNoteRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
 		return s
 	}
 	brainfstest.AssertNoLeak(t, p, "---\nx: y\n---\ninside", 1500*time.Millisecond, read)
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	brainfstest.AssertNoLeakFrom(t, p, "---\nx: y\n---\ninside", inBrain, 1500*time.Millisecond, read)
 	brainfstest.AssertNoHang(t, p, "---\nx: y\n---\ninside", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
 }

ingestion/internal/api/update_redirect_test.go

@@ -1,36 +0,0 @@
-package api_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
-)
-
-// hyperguild#173: a directory symlink inside wiki/ that points elsewhere in
-// the brain redirected brain_update's write (os.Root follows in-root
-// intermediate symlinks). Every directory above the note must be real.
-func TestUpdateNoteRefusesANoteBehindASymlinkedDirectory(t *testing.T) {
-	brain := t.TempDir()
-	victim := filepath.Join(brain, "raw", "facts", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("---\ntitle: v\n---\nuntouched\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(brain, "wiki", "w", "alias")))
-
-	_, _, _, err := api.UpdateNote(brain, api.UpdateNoteOptions{Path: "wiki/w/alias/v.md", Content: "replaced"})
-	assert.ErrorIs(t, err, brainfs.ErrNotRegular)
-	got, _ := os.ReadFile(victim)
-	assert.Contains(t, string(got), "untouched")
-
-	real := filepath.Join(brain, "wiki", "w", "facts", "r.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
-	require.NoError(t, os.WriteFile(real, []byte("---\ntitle: r\n---\nold\n"), 0o644))
-	_, _, _, err = api.UpdateNote(brain, api.UpdateNoteOptions{Path: "wiki/w/facts/r.md", Content: "new"})
-	require.NoError(t, err, "positive control: a note in a real directory is updated")
-}

ingestion/internal/api/write_redirect_test.go

@@ -1,43 +0,0 @@
-package api_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-)
-
-// hyperguild#188: brain_write created a new note with os.MkdirAll +
-// os.WriteFile by path, so a symlinked wing directory redirected the note
-// elsewhere in the brain or outside it.
-func TestWriteNoteRefusesASymlinkedWing(t *testing.T) {
-	for name, target := range map[string]func(t *testing.T, brain string) string{
-		"in-brain": func(t *testing.T, brain string) string {
-			require.NoError(t, os.MkdirAll(filepath.Join(brain, "raw"), 0o755))
-			return filepath.Join("..", "raw")
-		},
-		"outside": func(t *testing.T, _ string) string { return t.TempDir() },
-	} {
-		t.Run(name, func(t *testing.T) {
-			brain := t.TempDir()
-			require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
-			link := target(t, brain)
-			require.NoError(t, os.Symlink(link, filepath.Join(brain, "wiki", "lw")))
-			_, err := api.WriteNote(brain, api.WriteNoteOptions{Wing: "lw", Hall: "facts", Filename: "n", Content: "learning"})
-			assert.Error(t, err)
-			resolved := link
-			if !filepath.IsAbs(resolved) {
-				resolved = filepath.Join(brain, "wiki", link)
-			}
-			_, serr := os.Stat(filepath.Join(resolved, "facts"))
-			assert.True(t, os.IsNotExist(serr), "a hall was created at the link's target")
-
-			_, err = api.WriteNote(brain, api.WriteNoteOptions{Wing: "w", Hall: "facts", Filename: "n", Content: "learning"})
-			require.NoError(t, err, "positive control: a real wing is written")
-		})
-	}
-}

ingestion/internal/brain/detect_root_test.go

@@ -1,125 +0,0 @@
-package brain_test
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-	"syscall"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
-)
-
-// hyperguild#174 / #157 slice 5b: DetectTunnels walked wiki/ and opened
-// every note with a blocking os.Open, so a FIFO named *.md anywhere under
-// wiki/ hung every brain_write and brain_update (wikiUpkeep -> AutoTunnel),
-// and a symlinked note's title became a tunnel candidate.
-func TestDetectTunnelsReturnsPromptlyWithAFIFOUnderWikiWithAndWithoutAWriter(t *testing.T) {
-	for _, withWriter := range []bool{false, true} {
-		t.Run(fmt.Sprintf("writer=%v", withWriter), func(t *testing.T) {
-			b := t.TempDir()
-			facts := filepath.Join(b, "wiki", "w", "facts")
-			require.NoError(t, os.MkdirAll(facts, 0o755))
-			require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: Zqinside Phrase\n---\n"), 0o644))
-			fifo := filepath.Join(facts, "f.md")
-			require.NoError(t, syscall.Mkfifo(fifo, 0o644))
-			if withWriter {
-				// A writer held open: a reader that opens the FIFO gets no
-				// EOF and parks, unless the FIFO is never opened.
-				w, err := os.OpenFile(fifo, os.O_RDWR, 0)
-				require.NoError(t, err)
-				t.Cleanup(func() { _ = w.Close() })
-			}
-			done := make(chan []brain.TunnelCandidate, 1)
-			go func() {
-				cs, _ := brain.DetectTunnels(b, "text mentioning zqinside phrase here")
-				done <- cs
-			}()
-			select {
-			case cs := <-done:
-				assert.Contains(t, fmt.Sprintf("%+v", cs), "Zqinside Phrase", "positive control")
-			case <-time.After(3 * time.Second):
-				if r, err := os.OpenFile(fifo, os.O_WRONLY|syscall.O_NONBLOCK, 0); err == nil {
-					_ = r.Close()
-				}
-				t.Fatal("DetectTunnels blocked on a FIFO")
-			}
-		})
-	}
-}
-
-func TestDetectTunnelsRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
-	b := t.TempDir()
-	facts := filepath.Join(b, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	// The static note's title differs from the raced note's, so the
-	// harness's "inside was read" floor can only be met by reading r.md.
-	require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: Zqstatic Words\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "out.md")))
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(b, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "in.md")))
-	content := "zqstatic words, zqinside phrase and " + brainfstest.Sentinel
-
-	cs, err := brain.DetectTunnels(b, content)
-	require.NoError(t, err)
-	got := fmt.Sprintf("%+v", cs)
-	assert.Contains(t, got, "Zqstatic Words", "positive control")
-	assert.NotContains(t, got, brainfstest.Sentinel)
-
-	p := filepath.Join(facts, "r.md")
-	read := func() string {
-		cs, _ := brain.DetectTunnels(b, content)
-		return fmt.Sprintf("%+v", cs)
-	}
-	brainfstest.AssertNoLeak(t, p, "---\ntitle: Zqinside Phrase\n---\n", 1500*time.Millisecond, read)
-	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: Zqinside Phrase\n---\n", inBrain, 1500*time.Millisecond, read)
-}
-
-// A wiki/ that is not a real directory yields no candidates and no error:
-// AutoTunnel runs inside brain_write.
-func TestDetectTunnelsSkipsAWikiThatIsNotARealDirectory(t *testing.T) {
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "raw", "w", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "raw", "w", "facts", "r.md"), []byte("---\ntitle: Zqrawonly Phrase\n---\n"), 0o644))
-	require.NoError(t, os.Symlink("raw", filepath.Join(b, "wiki")))
-	cs, err := brain.DetectTunnels(b, "zqrawonly phrase")
-	require.NoError(t, err)
-	assert.Empty(t, cs)
-}
-
-// An unreadable directory under wiki/ is a walk error and DetectTunnels
-// reports it, as filepath.WalkDir did; it is not silently dropped.
-func TestDetectTunnelsReportsAnUnreadableDirectoryUnderWiki(t *testing.T) {
-	if os.Geteuid() == 0 {
-		t.Skip("root ignores directory permissions")
-	}
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "ok.md"), []byte("---\ntitle: Zqinside Phrase\n---\n"), 0o644))
-	locked := filepath.Join(b, "wiki", "other", "locked")
-	require.NoError(t, os.MkdirAll(locked, 0o755))
-	require.NoError(t, os.Chmod(locked, 0o000))
-	t.Cleanup(func() { _ = os.Chmod(locked, 0o755) })
-	_, err := brain.DetectTunnels(b, "zqinside phrase")
-	assert.ErrorIs(t, err, os.ErrPermission)
-}
-
-// _index.md files are generated, not notes: their title never becomes a
-// candidate.
-func TestDetectTunnelsSkipsIndexFiles(t *testing.T) {
-	b := t.TempDir()
-	w := filepath.Join(b, "wiki", "w")
-	require.NoError(t, os.MkdirAll(filepath.Join(w, "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(w, "_index.md"), []byte("---\ntitle: Zqindex Words\n---\n"), 0o644))
-	require.NoError(t, os.WriteFile(filepath.Join(w, "facts", "ok.md"), []byte("---\ntitle: Zqinside Phrase\n---\n"), 0o644))
-	cs, err := brain.DetectTunnels(b, "zqindex words and zqinside phrase")
-	require.NoError(t, err)
-	got := fmt.Sprintf("%+v", cs)
-	assert.Contains(t, got, "Zqinside Phrase", "positive control")
-	assert.NotContains(t, got, "Zqindex")
-}

ingestion/internal/brain/index.go

@@ -2,16 +2,12 @@ package brain
 
 import (
 	"bufio"
-	"bytes"
-	"errors"
 	"fmt"
-	"io"
+	"os"
-	"io/fs"
+	"path/filepath"
 	"sort"
 	"strings"
 	"time"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 )
 
 // noteEntry is one row in a Wing _index.md.
@@ -30,18 +26,14 @@ func BuildWingIndex(brainDir, wing string) error {
 	if w == "" {
 		return fmt.Errorf("invalid wing %q", wing)
 	}
-	// Listed and read through the brain root (hyperguild#157): a wing or
+	wingDir := filepath.Join(brainDir, "wiki", w)
-	// hall that is a symlink is not followed, and notes are regular files.
+	if _, err := os.Stat(wingDir); os.IsNotExist(err) {
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	if _, err := bfs.Lstat("wiki/" + w); errors.Is(err, fs.ErrNotExist) {
 		return nil
+	} else if err != nil {
+		return fmt.Errorf("stat wing: %w", err)
 	}
 
-	entries, err := collectWingEntries(bfs, "wiki/"+w)
+	entries, err := collectWingEntries(wingDir)
 	if err != nil {
 		return err
 	}
@@ -60,85 +52,74 @@ func BuildWingIndex(brainDir, wing string) error {
 		fmt.Fprintf(&b, "| %s | [%s](%s/%s.md) | %s |\n", e.Hall, e.Title, e.Hall, e.Slug, e.Created)
 	}
 
-	// Written through the brain root, never through a symlinked _index.md
+	dest := filepath.Join(wingDir, "_index.md")
-	// (hyperguild#158).
+	return os.WriteFile(dest, []byte(b.String()), 0o644)
-	return bfs.PutRegular("wiki/"+w+"/_index.md", []byte(b.String()))
 }
 
 // BuildAllWingIndexes regenerates _index.md for every wing under brain/wiki/.
 func BuildAllWingIndexes(brainDir string) error {
-	bfs, err := brainfs.Open(brainDir)
+	wikiDir := filepath.Join(brainDir, "wiki")
-	if err != nil {
+	ents, err := os.ReadDir(wikiDir)
-		return fmt.Errorf("open brain: %w", err)
+	if os.IsNotExist(err) {
-	}
-	wings, err := bfs.ReadDirDirs("wiki")
-	_ = bfs.Close()
-	if errors.Is(err, fs.ErrNotExist) {
 		return nil
 	}
 	if err != nil {
 		return fmt.Errorf("read wiki: %w", err)
 	}
-	for _, w := range wings {
+	for _, e := range ents {
-		if err := BuildWingIndex(brainDir, w); err != nil {
+		if !e.IsDir() {
-			return fmt.Errorf("index %s: %w", w, err)
+			continue
+		}
+		if err := BuildWingIndex(brainDir, e.Name()); err != nil {
+			return fmt.Errorf("index %s: %w", e.Name(), err)
 		}
 	}
 	return nil
 }
 
-func collectWingEntries(bfs *brainfs.Brain, wingRel string) ([]noteEntry, error) {
+func collectWingEntries(wingDir string) ([]noteEntry, error) {
 	var out []noteEntry
-	halls, err := bfs.ReadDirDirs(wingRel)
+	ents, err := os.ReadDir(wingDir)
 	if err != nil {
 		return nil, fmt.Errorf("read wing: %w", err)
 	}
-	for _, hall := range halls {
+	for _, hallEnt := range ents {
+		if !hallEnt.IsDir() {
+			continue
+		}
+		hall := hallEnt.Name()
 		if !IsValidHall(hall) {
 			continue
 		}
-		hallRel := wingRel + "/" + hall
+		hallDir := filepath.Join(wingDir, hall)
-		names, err := bfs.ReadDirRegular(hallRel)
+		notes, err := os.ReadDir(hallDir)
 		if err != nil {
 			return nil, fmt.Errorf("read hall %s: %w", hall, err)
 		}
-		for _, name := range names {
+		for _, n := range notes {
-			if !strings.HasSuffix(name, ".md") || name == "_index.md" {
+			if n.IsDir() || !strings.HasSuffix(n.Name(), ".md") || n.Name() == "_index.md" {
 				continue
 			}
-			slug := strings.TrimSuffix(name, ".md")
+			slug := strings.TrimSuffix(n.Name(), ".md")
-			title, created := readTitleAndCreatedIn(bfs, hallRel+"/"+name, slug)
+			full := filepath.Join(hallDir, n.Name())
+			title, created := readTitleAndCreated(full, slug)
 			out = append(out, noteEntry{Hall: hall, Slug: slug, Title: title, Created: created})
 		}
 	}
 	return out, nil
 }
 
-// readTitleAndCreatedIn is readTitleAndCreated through the brain root,
+// readTitleAndCreated reads YAML frontmatter for title + created_at; falls
-// regular files only (hyperguild#157).
+// back to slug and file mtime when absent.
-func readTitleAndCreatedIn(bfs *brainfs.Brain, rel, slug string) (string, string) {
+func readTitleAndCreated(path, slug string) (string, string) {
-	content, err := bfs.ReadRegular(rel)
+	f, err := os.Open(path)
 	if err != nil {
 		return slug, ""
 	}
-	title, created := parseTitleAndCreated(bytes.NewReader(content))
+	defer func() { _ = f.Close() }()
-	if created == "" {
-		if info, err := bfs.Lstat(rel); err == nil {
-			created = info.ModTime().UTC().Format("2006-01-02")
-		}
-	}
-	return titleOrSlug(title, slug), created
-}
 
-func titleOrSlug(title, slug string) string {
+	title, created := "", ""
-	if title == "" {
+	scanner := bufio.NewScanner(f)
-		return strings.ReplaceAll(slug, "-", " ")
-	}
-	return title
-}
-
-func parseTitleAndCreated(r io.Reader) (title, created string) {
-	scanner := bufio.NewScanner(r)
 	inFrontmatter := false
 	for scanner.Scan() {
 		line := scanner.Text()
@@ -168,5 +149,13 @@ func parseTitleAndCreated(r io.Reader) (title, created string) {
 			}
 		}
 	}
+	if title == "" {
+		title = strings.ReplaceAll(slug, "-", " ")
+	}
+	if created == "" {
+		if info, err := os.Stat(path); err == nil {
+			created = info.ModTime().UTC().Format("2006-01-02")
+		}
+	}
 	return title, created
 }

ingestion/internal/brain/index_root_test.go

@@ -1,132 +0,0 @@
-package brain_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
-)
-
-func readIndex(t *testing.T, brainDir, wing string) string {
-	t.Helper()
-	b, _ := os.ReadFile(filepath.Join(brainDir, "wiki", wing, "_index.md"))
-	return string(b)
-}
-
-// hyperguild#157 slice 5: BuildWingIndex listed wiki/<wing>/<hall>/ with
-// os.ReadDir and opened each note by path, so a symlinked note put the
-// target's title into _index.md, and a FIFO hung the index build.
-func TestBuildWingIndexRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
-	b := t.TempDir()
-	facts := filepath.Join(b, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: zqinside\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "leak.md")))
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(b, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-
-	require.NoError(t, brain.BuildWingIndex(b, "w"))
-	idx := readIndex(t, b, "w")
-	assert.Contains(t, idx, "zqinside", "positive control")
-	assert.NotContains(t, idx, brainfstest.Sentinel)
-	assert.NotContains(t, idx, "leak")
-	assert.NotContains(t, idx, "inlink")
-
-	p := filepath.Join(facts, "r.md")
-	read := func() string {
-		_ = brain.BuildWingIndex(b, "w")
-		return readIndex(t, b, "w")
-	}
-	brainfstest.AssertNoLeak(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, read)
-	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: zqinside\n---\n", inBrain, 1500*time.Millisecond, read)
-	brainfstest.AssertNoHang(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
-}
-
-// A symlinked hall is skipped while a real hall next to it is indexed; a
-// symlinked wing is refused and nothing is written into its target.
-func TestBuildWingIndexSkipsASymlinkedHallAndRefusesASymlinkedWing(t *testing.T) {
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "raw", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "raw", "facts", "r.md"), []byte("---\ntitle: zqrawonly\n---\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "decisions"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "decisions", "d.md"), []byte("---\ntitle: zqrealhall\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(b, "wiki", "w", "facts")))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(b, "wiki", "alias")))
-
-	require.NoError(t, brain.BuildWingIndex(b, "w"))
-	idx, err := os.ReadFile(filepath.Join(b, "wiki", "w", "_index.md"))
-	require.NoError(t, err, "the wing index is written")
-	assert.Contains(t, string(idx), "zqrealhall", "the real hall is indexed")
-	assert.NotContains(t, string(idx), "zqrawonly", "the symlinked hall is not")
-
-	assert.Error(t, brain.BuildWingIndex(b, "alias"))
-	_, err = os.Stat(filepath.Join(b, "raw", "_index.md"))
-	assert.True(t, os.IsNotExist(err), "an index was written into the symlinked wing's target")
-}
-
-// BuildAllWingIndexes indexes the real wings and skips a symlinked one.
-func TestBuildAllWingIndexesSkipsASymlinkedWing(t *testing.T) {
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "n.md"), []byte("---\ntitle: zqrealwing\n---\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "raw", "facts"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(b, "wiki", "alias")))
-
-	require.NoError(t, brain.BuildAllWingIndexes(b))
-	idx, err := os.ReadFile(filepath.Join(b, "wiki", "w", "_index.md"))
-	require.NoError(t, err)
-	assert.Contains(t, string(idx), "zqrealwing")
-	_, err = os.Stat(filepath.Join(b, "raw", "_index.md"))
-	assert.True(t, os.IsNotExist(err))
-}
-
-// A link to a symlinked note does not resolve: only regular files count as
-// entries, so StripUnresolvedLinks unwraps it.
-func TestStripUnresolvedLinksDoesNotCountASymlinkedNoteAsAnEntry(t *testing.T) {
-	b := t.TempDir()
-	facts := filepath.Join(b, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(facts, "real.md"), []byte("x"), 0o644))
-	brainfstest.WriteSentinelAt(t, filepath.Join(b, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "ghost.md")))
-	out, unlinked, err := brain.StripUnresolvedLinks(b, "see [[real]] and [[ghost]]")
-	require.NoError(t, err)
-	assert.Contains(t, out, "[[real]]", "positive control")
-	assert.NotContains(t, out, "[[ghost]]")
-	assert.Contains(t, unlinked, "ghost")
-}
-
-// A linked tree (knowledge/ or wiki/) that is not a real directory is
-// skipped, not an error: StripUnresolvedLinks runs before every brain_write,
-// and an error there loses the learning.
-func TestStripUnresolvedLinksSkipsALinkedTreeThatIsNotARealDirectory(t *testing.T) {
-	for name, mk := range map[string]func(t *testing.T, b string){
-		"symlink to an in-brain dir": func(t *testing.T, b string) {
-			require.NoError(t, os.MkdirAll(filepath.Join(b, "raw", "k"), 0o755))
-			require.NoError(t, os.Symlink(filepath.Join("raw", "k"), filepath.Join(b, "knowledge")))
-		},
-		"dangling symlink": func(t *testing.T, b string) {
-			require.NoError(t, os.Symlink("nowhere", filepath.Join(b, "knowledge")))
-		},
-		"regular file": func(t *testing.T, b string) {
-			require.NoError(t, os.WriteFile(filepath.Join(b, "knowledge"), []byte("x"), 0o644))
-		},
-	} {
-		t.Run(name, func(t *testing.T) {
-			b := t.TempDir()
-			require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
-			require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "real.md"), []byte("x"), 0o644))
-			mk(t, b)
-			out, _, err := brain.StripUnresolvedLinks(b, "learning [[real]] and [[gone]]")
-			require.NoError(t, err)
-			assert.Contains(t, out, "[[real]]", "links into wiki/ still resolve")
-			assert.NotContains(t, out, "[[gone]]")
-		})
-	}
-}

ingestion/internal/brain/linkcheck.go

@@ -1,16 +1,12 @@
 package brain
 
 import (
-	"errors"
 	"fmt"
-	"io/fs"
+	"os"
-	"log/slog"
+	"path/filepath"
-	"path"
 	"regexp"
 	"sort"
 	"strings"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 )
 
 // wikilinkRE matches [[target]] and [[target|Display Text]].
@@ -102,40 +98,29 @@ var linkedTrees = []string{"knowledge", "wiki"}
 // one the audit will also resolve.
 func entryIndex(brainDir string) (map[string]struct{}, error) {
 	index := map[string]struct{}{}
-	// Walked through the brain root (hyperguild#157): only regular files
-	// count as entries, so a symlinked .md name cannot make a link resolve.
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return nil, fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
 	for _, dir := range linkedTrees {
-		if _, err := bfs.Lstat(dir); errors.Is(err, fs.ErrNotExist) {
+		root := filepath.Join(brainDir, dir)
+		if _, err := os.Stat(root); os.IsNotExist(err) {
 			continue
+		} else if err != nil {
+			return nil, fmt.Errorf("stat %s: %w", dir, err)
 		}
-		var walkErr error
+		err := filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
-		err := bfs.WalkRegular(dir, func(rel string) error {
+			if err != nil {
-			if !strings.HasSuffix(rel, ".md") {
+				return err
+			}
+			if d.IsDir() || !strings.HasSuffix(path, ".md") {
 				return nil
 			}
-			index[strings.TrimSuffix(path.Base(rel), ".md")] = struct{}{}
+			rel, err := filepath.Rel(brainDir, path)
+			if err != nil {
+				return err
+			}
+			rel = filepath.ToSlash(rel)
+			index[strings.TrimSuffix(filepath.Base(rel), ".md")] = struct{}{}
 			index[strings.TrimPrefix(strings.TrimSuffix(rel, ".md"), "wiki/")] = struct{}{}
 			return nil
-		}, func(rel string, err error) {
-			// A linked tree that is not a real directory (a symlink, a
-			// file) is skipped, as filepath.WalkDir did: this runs before
-			// every brain_write, and an error here loses the learning.
-			if rel == dir && errors.Is(err, brainfs.ErrNotRegular) {
-				slog.Warn("link check: skipping a linked tree that is not a real directory", "dir", dir)
-				return
-			}
-			if walkErr == nil {
-				walkErr = fmt.Errorf("%s: %w", rel, err)
-			}
 		})
-		if err == nil {
-			err = walkErr
-		}
 		if err != nil {
 			return nil, fmt.Errorf("walk %s: %w", dir, err)
 		}

ingestion/internal/brain/tunnel.go

@@ -2,9 +2,8 @@ package brain
 
 import (
 	"bufio"
-	"errors"
 	"fmt"
-	"io/fs"
+	"os"
 	"path"
 	"path/filepath"
 	"strings"
@@ -40,29 +39,24 @@ type TunnelCandidate struct {
 // A note's title is read from YAML frontmatter `title:`; failing that,
 // the filename slug (sans `.md`, hyphens → spaces) is used.
 func DetectTunnels(brainDir, content string) ([]TunnelCandidate, error) {
-	// Walked and read through the brain root, regular files only
+	wikiDir := filepath.Join(brainDir, "wiki")
-	// (hyperguild#174, #157): this runs inside every brain_write, so a FIFO
+	if _, err := os.Stat(wikiDir); os.IsNotExist(err) {
-	// must not block it and a symlinked note's title must not become a
-	// candidate.
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return nil, fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	if _, err := bfs.Lstat("wiki"); errors.Is(err, fs.ErrNotExist) {
 		return nil, nil
+	} else if err != nil {
+		return nil, fmt.Errorf("stat wiki: %w", err)
 	}
 
 	lowerContent := strings.ToLower(content)
 
 	var out []TunnelCandidate
-	var walkErr error
+	err := filepath.WalkDir(wikiDir, func(path string, d os.DirEntry, err error) error {
-	err = bfs.WalkRegular("wiki", func(rel string) error {
+		if err != nil {
-		name := path.Base(rel)
+			return err
-		if !strings.HasSuffix(name, ".md") || name == "_index.md" {
+		}
+		if d.IsDir() || !strings.HasSuffix(path, ".md") || d.Name() == "_index.md" {
 			return nil
 		}
-		title, _ := readTitleAndCreatedIn(bfs, rel, strings.TrimSuffix(name, ".md"))
+		title, _ := readTitleAndCreated(path, strings.TrimSuffix(d.Name(), ".md"))
 		title = strings.TrimSpace(title)
 		if title == "" {
 			return nil
@@ -84,25 +78,17 @@ func DetectTunnels(brainDir, content string) ([]TunnelCandidate, error) {
 		if idx == -1 {
 			return nil
 		}
+		rel, err := filepath.Rel(brainDir, path)
+		if err != nil {
+			return err
+		}
 		out = append(out, TunnelCandidate{
-			TargetPath:  rel,
+			TargetPath:  filepath.ToSlash(rel),
 			MatchedTerm: title,
 			Exact:       isWholeWord(haystack, idx, len(needle)),
 		})
 		return nil
-	}, func(rel string, err error) {
-		// A wiki/ that is not a real directory yields no candidates, as
-		// filepath.WalkDir did; other walk errors still abort.
-		if rel == "wiki" && errors.Is(err, brainfs.ErrNotRegular) {
-			return
-		}
-		if walkErr == nil {
-			walkErr = fmt.Errorf("%s: %w", rel, err)
-		}
 	})
-	if err == nil {
-		err = walkErr
-	}
 	if err != nil {
 		return nil, err
 	}
@@ -175,23 +161,35 @@ func logFuzzyCandidates(brainDir, sourcePath string, cs []TunnelCandidate) error
 	if len(cs) == 0 {
 		return nil
 	}
-	// Appended through the brain root, never through a symlinked raw/ or
+	rawDir := filepath.Join(brainDir, "raw")
-	// log file (hyperguild#158).
+	if err := os.MkdirAll(rawDir, 0o755); err != nil {
-	bfs, err := brainfs.Open(brainDir)
+		return err
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
 	}
-	defer func() { _ = bfs.Close() }()
 	stamp := time.Now().UTC().Format("2006-01-02")
-	rel := "raw/tunnel-candidates-" + stamp + ".md"
+	path := filepath.Join(rawDir, "tunnel-candidates-"+stamp+".md")
-	var buf strings.Builder
+	existed := fileExists(path)
-	if _, err := bfs.Lstat(rel); errors.Is(err, fs.ErrNotExist) {
+	f, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
-		buf.WriteString("# Tunnel candidates " + stamp + "\n\nFuzzy cross-wing matches surfaced by AutoTunnel. Review and promote to a tunnel via `brain_tunnel` if relevant.\n\n")
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+	if !existed {
+		if _, err := f.WriteString("# Tunnel candidates " + stamp + "\n\nFuzzy cross-wing matches surfaced by AutoTunnel. Review and promote to a tunnel via `brain_tunnel` if relevant.\n\n"); err != nil {
+			return err
+		}
 	}
 	for _, c := range cs {
-		fmt.Fprintf(&buf, "- `%s` ↔ `%s` (term: %q)\n", sourcePath, c.TargetPath, c.MatchedTerm)
+		line := fmt.Sprintf("- `%s` ↔ `%s` (term: %q)\n", sourcePath, c.TargetPath, c.MatchedTerm)
+		if _, err := f.WriteString(line); err != nil {
+			return err
+		}
 	}
-	return bfs.AppendRegular(rel, []byte(buf.String()))
+	return nil
+}
+
+func fileExists(p string) bool {
+	_, err := os.Stat(p)
+	return err == nil
 }
 
 // WriteTunnel appends a bidirectional wikilink between sourcePath and

ingestion/internal/brain/tunnel_redirect_test.go

@@ -1,38 +0,0 @@
-package brain_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
-)
-
-// hyperguild#173: brain_tunnel's write followed a directory symlink inside
-// wiki/ that points elsewhere in the brain.
-func TestWriteTunnelRefusesATargetBehindASymlinkedDirectory(t *testing.T) {
-	b := t.TempDir()
-	src := filepath.Join(b, "wiki", "a", "facts", "s.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(src), 0o755))
-	require.NoError(t, os.WriteFile(src, []byte("x\n"), 0o644))
-	victim := filepath.Join(b, "raw", "facts", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "b"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(b, "wiki", "b", "facts")))
-
-	assert.ErrorIs(t, brain.WriteTunnel(b, "wiki/a/facts/s.md", "wiki/b/facts/v.md"), brainfs.ErrNotRegular)
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched\n", string(got))
-	got, _ = os.ReadFile(src)
-	assert.Equal(t, "x\n", string(got), "the source is not rewritten either")
-
-	real := filepath.Join(b, "wiki", "c", "facts", "t.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
-	require.NoError(t, os.WriteFile(real, []byte("t\n"), 0o644))
-	require.NoError(t, brain.WriteTunnel(b, "wiki/a/facts/s.md", "wiki/c/facts/t.md"), "positive control: a tunnel between real directories is written")
-}

ingestion/internal/brain/writers_redirect_test.go

@@ -1,52 +0,0 @@
-package brain_test
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-)
-
-// hyperguild#158: BuildWingIndex wrote wiki/<wing>/_index.md with
-// os.WriteFile, so a symlinked _index.md was written through.
-func TestBuildWingIndexDoesNotWriteThroughASymlinkedIndex(t *testing.T) {
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "w", "facts", "n.md"), []byte("---\ntitle: zqn\n---\n"), 0o644))
-	victim := filepath.Join(b, "raw", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "v.md"), filepath.Join(b, "wiki", "w", "_index.md")))
-	assert.Error(t, brain.BuildWingIndex(b, "w"))
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched", string(got))
-
-	require.NoError(t, os.Remove(filepath.Join(b, "wiki", "w", "_index.md")))
-	require.NoError(t, brain.BuildWingIndex(b, "w"), "positive control")
-	idx, _ := os.ReadFile(filepath.Join(b, "wiki", "w", "_index.md"))
-	assert.Contains(t, string(idx), "zqn")
-}
-
-// AutoTunnel's fuzzy-candidate log appended to raw/tunnel-candidates-*.md
-// with os.OpenFile, so a symlinked raw/ (or log file) was written through.
-func TestAutoTunnelDoesNotAppendTheCandidateLogThroughASymlinkedRaw(t *testing.T) {
-	b := t.TempDir()
-	outside := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "a", "facts"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "b", "facts"), 0o755))
-	// "zq widget" matches as a substring of "zq widgets", a fuzzy candidate.
-	require.NoError(t, os.WriteFile(filepath.Join(b, "wiki", "b", "facts", "t.md"), []byte("---\ntitle: Zq Widget\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(outside, filepath.Join(b, "raw")))
-	_ = brain.AutoTunnel(b, "wiki/a/facts/s.md", "about zq widgets")
-	ents, _ := os.ReadDir(outside)
-	assert.Empty(t, ents, "the candidate log was written outside the brain")
-
-	require.NoError(t, os.Remove(filepath.Join(b, "raw")))
-	require.NoError(t, brain.AutoTunnel(b, "wiki/a/facts/s.md", "about zq widgets"))
-	logs, _ := filepath.Glob(filepath.Join(b, "raw", "tunnel-candidates-*.md"))
-	assert.Len(t, logs, 1, "positive control: the fuzzy candidate is logged in the real raw/")
-}

ingestion/internal/brainfs/brainfs.go

@@ -82,203 +82,47 @@ func (b *Brain) realDir(rel string) error {
 	return nil
 }
 
-// ReadDirRegular lists the regular files directly in a brain-relative
+// WriteRegular replaces the contents of an existing regular file at a
-// directory, by name. Every component of relDir must be a real directory
+// brain-relative path. It never creates a file and never writes through a
-// (ErrNotRegular otherwise); symlinks, FIFOs, devices and subdirectories in
+// final symlink: os.Root.OpenFile follows an in-root final symlink even with
-// it are left out.
+// O_NOFOLLOW (verified on go1.27), so the path is Lstat-ed through the root
-func (b *Brain) ReadDirRegular(relDir string) ([]string, error) {
+// first and the opened handle must be that same file (os.SameFile), which
-	relDir = filepath.ToSlash(relDir)
+// also catches a swap between the two. O_NONBLOCK keeps a FIFO from blocking
-	if err := b.realDir(relDir); err != nil {
+// the open. Intermediate in-brain symlinks are still followed (os.Root keeps
-		return nil, err
+// the write inside the brain; hyperguild#167).
-	}
+func (b *Brain) WriteRegular(rel string, data []byte) error {
-	ents, err := fs.ReadDir(b.root.FS(), relDir)
+	rel = filepath.ToSlash(rel)
-	if err != nil {
+	lfi, err := b.root.Lstat(rel)
-		return nil, err
-	}
-	var names []string
-	for _, e := range ents {
-		if e.Type().IsRegular() {
-			names = append(names, e.Name())
-		}
-	}
-	return names, nil
-}
-
-// cleanRel refuses a path that is not clean and local. realDir checks the
-// cleaned parent, so the I/O must use that same path: os.Root resolves ".."
-// after following a symlink, and a ".." after a symlinked directory would
-// otherwise pass the check and redirect the read or write.
-func cleanRel(rel string) error {
-	if rel == "" || path.Clean(rel) != rel || !filepath.IsLocal(rel) || strings.Contains(rel, "\\") {
-		return fmt.Errorf("%q: not a clean brain-relative path: %w", rel, ErrNotRegular)
-	}
-	return nil
-}
-
-// ReadDirDirs lists the real subdirectories directly in a brain-relative
-// directory, by name. Every component of relDir must be a real directory
-// (ErrNotRegular otherwise); symlinks to directories are left out.
-func (b *Brain) ReadDirDirs(relDir string) ([]string, error) {
-	relDir = filepath.ToSlash(relDir)
-	if err := b.realDir(relDir); err != nil {
-		return nil, err
-	}
-	ents, err := fs.ReadDir(b.root.FS(), relDir)
-	if err != nil {
-		return nil, err
-	}
-	var names []string
-	for _, e := range ents {
-		if e.Type().IsDir() {
-			names = append(names, e.Name())
-		}
-	}
-	return names, nil
-}
-
-// PutRegular creates or replaces a regular file at a brain-relative path,
-// for creating writes (hyperguild#188, #158). Missing parent directories are
-// created one component at a time through the root, and every existing
-// component must be a real directory, so a symlinked directory cannot
-// redirect the write elsewhere in the brain or outside it. An existing file
-// is replaced only if it is regular (WriteRegular's checks); a new file is
-// created with O_EXCL and confirmed to be the file that was opened. A
-// directory swapped in after the checks is the #167 residual.
-func (b *Brain) PutRegular(rel string, data []byte) error {
-	if err := cleanRel(rel); err != nil {
-		return err
-	}
-	if err := b.mkdirReal(path.Dir(rel)); err != nil {
-		return err
-	}
-	if _, err := b.root.Lstat(rel); err == nil {
-		return b.WriteRegular(rel, data)
-	} else if !errors.Is(err, fs.ErrNotExist) {
-		return err
-	}
-	return b.createNew(rel, data)
-}
-
-// CreateRegular creates a new regular file at a brain-relative path, with
-// PutRegular's parent rules, and fails with fs.ErrExist if anything is
-// already there: for writers that must never overwrite (promote, reject).
-func (b *Brain) CreateRegular(rel string, data []byte) error {
-	if err := cleanRel(rel); err != nil {
-		return err
-	}
-	if err := b.mkdirReal(path.Dir(rel)); err != nil {
-		return err
-	}
-	return b.createNew(rel, data)
-}
-
-// createNew creates rel with O_EXCL and writes data only after confirming
-// the path is the regular file it created.
-func (b *Brain) createNew(rel string, data []byte) error {
-	f, err := b.root.OpenFile(rel, os.O_WRONLY|os.O_CREATE|os.O_EXCL|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
 	if err != nil {
 		return err
 	}
-	defer func() { _ = f.Close() }()
+	if !lfi.Mode().IsRegular() {
-	hfi, herr := f.Stat()
-	lfi, lerr := b.root.Lstat(rel)
-	if herr != nil || lerr != nil || !lfi.Mode().IsRegular() || !os.SameFile(lfi, hfi) {
-		return fmt.Errorf("%s: changed while creating: %w", rel, ErrNotRegular)
-	}
-	if _, err := f.Write(data); err != nil {
-		return err
-	}
-	return f.Close()
-}
-
-// AppendRegular appends data to a regular file at a brain-relative path,
-// creating it (and missing parent directories, as PutRegular does) if it is
-// absent. It writes only after confirming the path is the regular file it
-// opened, so a final symlink or special file, or one swapped in, is refused.
-func (b *Brain) AppendRegular(rel string, data []byte) error {
-	if err := cleanRel(rel); err != nil {
-		return err
-	}
-	if err := b.mkdirReal(path.Dir(rel)); err != nil {
-		return err
-	}
-	if fi, err := b.root.Lstat(rel); err == nil && !fi.Mode().IsRegular() {
 		return fmt.Errorf("%s: %w", rel, ErrNotRegular)
-	} else if err != nil && !errors.Is(err, fs.ErrNotExist) {
-		return err
 	}
-	f, err := b.root.OpenFile(rel, os.O_WRONLY|os.O_APPEND|os.O_CREATE|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
+	f, err := b.root.OpenFile(rel, os.O_WRONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
 	if err != nil {
 		return err
 	}
 	defer func() { _ = f.Close() }()
-	hfi, herr := f.Stat()
+	fi, err := f.Stat()
-	lfi, lerr := b.root.Lstat(rel)
+	if err != nil {
-	if herr != nil || lerr != nil || !lfi.Mode().IsRegular() || !os.SameFile(lfi, hfi) {
+		return err
+	}
+	if !fi.Mode().IsRegular() || !os.SameFile(lfi, fi) {
 		return fmt.Errorf("%s: changed while opening: %w", rel, ErrNotRegular)
 	}
+	if err := f.Truncate(0); err != nil {
+		return err
+	}
 	if _, err := f.Write(data); err != nil {
 		return err
 	}
 	return f.Close()
 }
 
-// Remove removes the file at a clean brain-relative path through the root,
-// refusing a path behind a symlinked directory. A final symlink is removed
-// itself, never its target.
-func (b *Brain) Remove(rel string) error {
-	if err := b.RealParent(rel); err != nil {
-		return err
-	}
-	return b.root.Remove(rel)
-}
-
-// RealParent returns ErrNotRegular unless rel is clean and every directory
-// above it is a real directory, for writers that do their own I/O (an atomic
-// rename) but must not be redirected by a symlinked directory.
-func (b *Brain) RealParent(rel string) error {
-	if err := cleanRel(rel); err != nil {
-		return err
-	}
-	return b.realDir(path.Dir(rel))
-}
-
-// mkdirReal makes sure every component of rel exists as a real directory,
-// creating missing ones through the root; an existing component that is
-// not a real directory is ErrNotRegular.
-func (b *Brain) mkdirReal(rel string) error {
-	if rel == "." {
-		return nil
-	}
-	prefix := ""
-	for _, part := range strings.Split(rel, "/") {
-		prefix = path.Join(prefix, part)
-		fi, err := b.root.Lstat(prefix)
-		if errors.Is(err, fs.ErrNotExist) {
-			if err := b.root.Mkdir(prefix, 0o755); err != nil && !errors.Is(err, fs.ErrExist) {
-				return err
-			}
-			fi, err = b.root.Lstat(prefix)
-		}
-		if err != nil {
-			return err
-		}
-		if !fi.IsDir() {
-			return fmt.Errorf("%s: component %s is not a directory: %w", rel, prefix, ErrNotRegular)
-		}
-	}
-	return nil
-}
-
 // ReadRegular reads a brain-relative path, refusing anything that is not a
 // regular file, both before the open and on the opened handle.
 func (b *Brain) ReadRegular(rel string) ([]byte, error) {
-	if err := cleanRel(rel); err != nil {
-		return nil, err
-	}
-	if err := b.realDir(path.Dir(rel)); err != nil {
-		return nil, err
-	}
 	fi, err := b.root.Lstat(rel)
 	if err != nil {
 		return nil, err
@@ -286,7 +130,7 @@ func (b *Brain) ReadRegular(rel string) ([]byte, error) {
 	if !fi.Mode().IsRegular() {
 		return nil, fmt.Errorf("%s: %w", rel, ErrNotRegular)
 	}
-	return b.readOpenedMax(rel, -1, fi)
+	return b.readOpened(rel)
 }
 
 // readOpened opens rel non-blocking and reads it only if the OPENED handle is
@@ -300,17 +144,11 @@ func (b *Brain) ReadRegular(rel string) ([]byte, error) {
 // cannot create one; fs.protected_hardlinks=1 and the pod's secrets are on a
 // different filesystem from the brain volume, so a local caller cannot link
 // them in. Refusing Nlink > 1 is the next step if either changes.
-func (b *Brain) readOpened(rel string) ([]byte, error) { return b.readOpenedMax(rel, -1, nil) }
+func (b *Brain) readOpened(rel string) ([]byte, error) { return b.readOpenedMax(rel, -1) }
 
 // ReadRegularMax is ReadRegular with a size limit, checked on the opened
 // handle before reading (max < 0 means no limit).
 func (b *Brain) ReadRegularMax(rel string, max int64) ([]byte, error) {
-	if err := cleanRel(rel); err != nil {
-		return nil, err
-	}
-	if err := b.realDir(path.Dir(rel)); err != nil {
-		return nil, err
-	}
 	fi, err := b.root.Lstat(rel)
 	if err != nil {
 		return nil, err
@@ -318,14 +156,10 @@ func (b *Brain) ReadRegularMax(rel string, max int64) ([]byte, error) {
 	if !fi.Mode().IsRegular() {
 		return nil, fmt.Errorf("%s: %w", rel, ErrNotRegular)
 	}
-	return b.readOpenedMax(rel, max, fi)
+	return b.readOpenedMax(rel, max)
 }
 
-// readOpenedMax opens rel and reads it if the opened handle is a regular file
+func (b *Brain) readOpenedMax(rel string, max int64) ([]byte, error) {
-// and, when lfi is set, the same file the caller Lstat-ed: os.Root follows an
-// in-root final symlink even with O_NOFOLLOW, so a symlink to another brain
-// file swapped in between the Lstat and the open is refused only here.
-func (b *Brain) readOpenedMax(rel string, max int64, lfi fs.FileInfo) ([]byte, error) {
 	f, err := b.root.OpenFile(rel, os.O_RDONLY|syscall.O_NONBLOCK, 0)
 	if err != nil {
 		return nil, err
@@ -338,9 +172,6 @@ func (b *Brain) readOpenedMax(rel string, max int64, lfi fs.FileInfo) ([]byte, e
 	if !hfi.Mode().IsRegular() {
 		return nil, fmt.Errorf("%s: %w", rel, ErrNotRegular)
 	}
-	if lfi != nil && !os.SameFile(lfi, hfi) {
-		return nil, fmt.Errorf("%s: changed while opening: %w", rel, ErrNotRegular)
-	}
 	if max >= 0 && hfi.Size() > max {
 		return nil, fmt.Errorf("%s is %d bytes (limit %d): %w", rel, hfi.Size(), max, ErrTooLarge)
 	}
@@ -406,51 +237,3 @@ func (b *Brain) WalkRegular(relDir string, fn func(rel string) error, onErr func
 		return fn(p)
 	})
 }
-
-// WriteRegular replaces the contents of an existing regular file at a
-// brain-relative path. It never creates a file and never writes through a
-// final symlink: os.Root.OpenFile follows an in-root final symlink even with
-// O_NOFOLLOW (verified on go1.27), so the path is Lstat-ed through the root
-// first and the opened handle must be that same file (os.SameFile), which
-// also catches a swap between the two. O_NONBLOCK keeps a FIFO from blocking
-// the open. Every directory above the file must be a real directory
-// (hyperguild#173); a directory swapped in after that check is the #167
-// residual.
-func (b *Brain) WriteRegular(rel string, data []byte) error {
-	if err := cleanRel(rel); err != nil {
-		return err
-	}
-	// Every directory above the file must be real: os.Root follows an
-	// in-brain intermediate symlink, which would redirect the write
-	// elsewhere in the brain (hyperguild#173). A swap after this check is
-	// the #167 residual.
-	if err := b.realDir(path.Dir(rel)); err != nil {
-		return err
-	}
-	lfi, err := b.root.Lstat(rel)
-	if err != nil {
-		return err
-	}
-	if !lfi.Mode().IsRegular() {
-		return fmt.Errorf("%s: %w", rel, ErrNotRegular)
-	}
-	f, err := b.root.OpenFile(rel, os.O_WRONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
-	if err != nil {
-		return err
-	}
-	defer func() { _ = f.Close() }()
-	fi, err := f.Stat()
-	if err != nil {
-		return err
-	}
-	if !fi.Mode().IsRegular() || !os.SameFile(lfi, fi) {
-		return fmt.Errorf("%s: changed while opening: %w", rel, ErrNotRegular)
-	}
-	if err := f.Truncate(0); err != nil {
-		return err
-	}
-	if _, err := f.Write(data); err != nil {
-		return err
-	}
-	return f.Close()
-}

ingestion/internal/brainfs/brainfs_test.go

@@ -6,8 +6,6 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
-	"sync"
-	"sync/atomic"
 	"syscall"
 	"testing"
 	"time"
@@ -192,77 +190,6 @@ func TestWalkRegularReportsASymlinkedIntermediateComponentOfTheWalkRoot(t *testi
 	assert.ErrorIs(t, errs[0], ErrNotRegular)
 }
 
-func TestReadDirRegularListsOnlyRegularFilesAndRefusesSymlinkedComponents(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "a", "b", "sub"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "a", "b", "n.md"), []byte("n"), 0o644))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "other.md"), []byte("o"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "other.md"), filepath.Join(dir, "a", "b", "l.md")))
-	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "a", "b", "f.md"), 0o644))
-	require.NoError(t, os.Symlink("a", filepath.Join(dir, "alias")))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "x"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "a"), filepath.Join(dir, "x", "mid")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	names, err := b.ReadDirRegular("a/b")
-	require.NoError(t, err)
-	assert.Equal(t, []string{"n.md"}, names)
-	for _, rel := range []string{"alias/b", "x/mid/b"} {
-		_, err := b.ReadDirRegular(rel)
-		assert.ErrorIs(t, err, ErrNotRegular, rel)
-	}
-}
-
-// A final component swapped for a symlink to another regular file in the
-// brain between the Lstat and the open: os.Root follows in-root links, so
-// only comparing the two (os.SameFile) refuses it.
-func TestReadRegularDoesNotReturnAnInBrainFileSwappedInBehindASymlink(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "s.md"), []byte("zqsamefilesentinel"), 0o644))
-	p := filepath.Join(dir, "r.md")
-	require.NoError(t, os.WriteFile(p, []byte("inside"), 0o644))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	var stop atomic.Bool
-	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		tmp := p + ".swap"
-		for i := 0; !stop.Load(); i++ {
-			_ = os.Remove(tmp)
-			if i%2 == 0 {
-				_ = os.WriteFile(tmp, []byte("inside"), 0o644)
-			} else {
-				_ = os.Symlink("s.md", tmp)
-			}
-			_ = os.Rename(tmp, p)
-		}
-	}()
-	leaks, ok := 0, 0
-	for deadline := time.Now().Add(1500 * time.Millisecond); time.Now().Before(deadline); {
-		got, err := b.ReadRegular("r.md")
-		if err == nil {
-			ok++
-		}
-		if string(got) == "zqsamefilesentinel" {
-			leaks++
-		}
-		got, _ = b.ReadRegularMax("r.md", 1<<20)
-		if string(got) == "zqsamefilesentinel" {
-			leaks++
-		}
-	}
-	stop.Store(true)
-	wg.Wait()
-	assert.Zero(t, leaks)
-	assert.Positive(t, ok, "positive control: the regular file is read")
-}
-
 func TestWriteRegularRefusesFinalSymlinksFIFOsEscapesAndMissingFilesAndRewritesRegularFiles(t *testing.T) {
 	dir := t.TempDir()
 	outside := filepath.Join(t.TempDir(), "o.md")
@@ -308,224 +235,3 @@ func TestWriteRegularRefusesFinalSymlinksFIFOsEscapesAndMissingFilesAndRewritesR
 	got, _ = os.ReadFile(filepath.Join(dir, "n.md"))
 	assert.Equal(t, "new", string(got), "truncated and rewritten")
 }
-
-func TestReadDirDirsListsOnlyRealSubdirsAndRefusesSymlinkedComponents(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "a", "real"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "other"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "other"), filepath.Join(dir, "a", "linked")))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "a", "f.md"), []byte("f"), 0o644))
-	require.NoError(t, os.Symlink("a", filepath.Join(dir, "alias")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	names, err := b.ReadDirDirs("a")
-	require.NoError(t, err)
-	assert.Equal(t, []string{"real"}, names)
-	_, err = b.ReadDirDirs("alias")
-	assert.ErrorIs(t, err, ErrNotRegular)
-}
-
-// hyperguild#173: a file reached through a symlinked directory inside the
-// brain is refused for reads and writes, so a caller-supplied path cannot be
-// redirected to another part of the brain.
-func TestReadAndWriteRegularRefuseAFileBehindASymlinkedDirectory(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "alias")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	_, err = b.ReadRegular("wiki/alias/v.md")
-	assert.ErrorIs(t, err, ErrNotRegular)
-	_, err = b.ReadRegularMax("wiki/alias/v.md", 100)
-	assert.ErrorIs(t, err, ErrNotRegular)
-	assert.ErrorIs(t, b.WriteRegular("wiki/alias/v.md", []byte("x")), ErrNotRegular)
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-	got, err = b.ReadRegular("raw/v.md")
-	require.NoError(t, err, "positive control: the real path still reads")
-	assert.Equal(t, "untouched", string(got))
-}
-
-// realDir checks the cleaned parent, so the I/O must use that same clean
-// path: os.Root resolves ".." after following a symlink, and a ".." placed
-// after a symlinked directory would otherwise pass the check and redirect.
-func TestReadAndWriteRegularRefuseAPathThatIsNotClean(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw", "facts"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw", "facts"), filepath.Join(dir, "wiki", "alias")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	for _, rel := range []string{"wiki/alias/../v.md", "./raw/v.md", "raw//v.md", "/raw/v.md"} {
-		got, err := b.ReadRegular(rel)
-		assert.ErrorIs(t, err, ErrNotRegular, rel)
-		assert.NotContains(t, string(got), "untouched", rel)
-		_, err = b.ReadRegularMax(rel, 100)
-		assert.ErrorIs(t, err, ErrNotRegular, rel)
-		assert.ErrorIs(t, b.WriteRegular(rel, []byte("OVERWRITTEN")), ErrNotRegular, rel)
-	}
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-}
-
-// hyperguild#188: PutRegular creates or replaces a regular file through the
-// root. Missing parent directories are created; an existing component that
-// is not a real directory, a final symlink or special file, and an unclean
-// path are refused, and nothing is created at a link's target.
-func TestPutRegularCreatesOrReplacesOnlyThroughRealDirectories(t *testing.T) {
-	dir := t.TempDir()
-	outside := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "inwing")))
-	require.NoError(t, os.Symlink(outside, filepath.Join(dir, "wiki", "outwing")))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki", "w"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "v.md"), filepath.Join(dir, "wiki", "w", "link.md")))
-	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "wiki", "w", "f.md"), 0o644))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	for _, rel := range []string{"wiki/inwing/facts/n.md", "wiki/outwing/facts/n.md", "wiki/w/link.md", "wiki/w/f.md", "wiki/w/../../raw/v.md", "/abs.md"} {
-		assert.ErrorIs(t, b.PutRegular(rel, []byte("x")), ErrNotRegular, rel)
-	}
-	ents, _ := os.ReadDir(outside)
-	assert.Empty(t, ents, "nothing created outside the brain")
-	_, err = os.Stat(filepath.Join(dir, "raw", "facts"))
-	assert.True(t, os.IsNotExist(err), "nothing created through the in-brain link")
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-
-	require.NoError(t, b.PutRegular("wiki/new/facts/n.md", []byte("one")), "positive control: create with missing parents")
-	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
-	assert.Equal(t, "one", string(got))
-	require.NoError(t, b.PutRegular("wiki/new/facts/n.md", []byte("two")), "positive control: replace")
-	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
-	assert.Equal(t, "two", string(got))
-}
-
-func TestAppendRegularCreatesOrAppendsOnlyThroughRealDirectories(t *testing.T) {
-	dir := t.TempDir()
-	outside := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(outside, filepath.Join(dir, "outdir")))
-	require.NoError(t, os.Symlink("raw", filepath.Join(dir, "indir")))
-	require.NoError(t, os.Symlink(filepath.Join("raw", "v.md"), filepath.Join(dir, "log.md")))
-	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "f.md"), 0o644))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	for _, rel := range []string{"outdir/l.md", "indir/v.md", "log.md", "f.md", "raw/../log.md"} {
-		assert.ErrorIs(t, b.AppendRegular(rel, []byte("x")), ErrNotRegular, rel)
-	}
-	ents, _ := os.ReadDir(outside)
-	assert.Empty(t, ents)
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-
-	require.NoError(t, b.AppendRegular("logs/a.md", []byte("one\n")), "positive control: create")
-	require.NoError(t, b.AppendRegular("logs/a.md", []byte("two\n")), "positive control: append")
-	got, _ = os.ReadFile(filepath.Join(dir, "logs", "a.md"))
-	assert.Equal(t, "one\ntwo\n", string(got))
-}
-
-func TestRealParentRefusesASymlinkedDirectoryOrUncleanPath(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "alias")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-	assert.ErrorIs(t, b.RealParent("wiki/alias/x.md"), ErrNotRegular)
-	assert.ErrorIs(t, b.RealParent("wiki/../raw/x.md"), ErrNotRegular)
-	assert.NoError(t, b.RealParent("wiki/x.md"), "positive control")
-}
-
-// cleanRel must refuse an unclean path on its own: here the ".." resolves,
-// after a symlinked directory, to a real regular file, so only the clean
-// check stands between the call and that file.
-func TestAppendRegularRefusesAnUncleanPathThatResolvesToARealFile(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw", "keep"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("raw", "keep"), filepath.Join(dir, "indir")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-	assert.ErrorIs(t, b.AppendRegular("indir/../v.md", []byte("x")), ErrNotRegular)
-	assert.ErrorIs(t, b.PutRegular("indir/../v.md", []byte("x")), ErrNotRegular)
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-}
-
-func TestRemoveRefusesAPathBehindASymlinkedDirectoryAndRemovesOnlyTheLink(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("keep"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "alias")))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw", "v.md"), filepath.Join(dir, "wiki", "link.md")))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "wiki", "n.md"), []byte("n"), 0o644))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	assert.ErrorIs(t, b.Remove("wiki/alias/v.md"), ErrNotRegular)
-	_, err = os.Stat(filepath.Join(dir, "raw", "v.md"))
-	assert.NoError(t, err, "the file behind the symlinked directory is kept")
-	require.NoError(t, b.Remove("wiki/link.md"))
-	_, err = os.Stat(filepath.Join(dir, "raw", "v.md"))
-	assert.NoError(t, err, "removing a final symlink never removes its target")
-	require.NoError(t, b.Remove("wiki/n.md"), "positive control")
-	_, err = os.Stat(filepath.Join(dir, "wiki", "n.md"))
-	assert.True(t, os.IsNotExist(err))
-}
-
-// CreateRegular is the only write path for promote and reject: it creates
-// missing parents through the root, refuses an in-brain symlinked parent and
-// an unclean path, and never replaces anything already there (fs.ErrExist,
-// content unchanged), including a dangling link.
-func TestCreateRegularCreatesOnlyNewFilesThroughRealDirectories(t *testing.T) {
-	dir := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "raw", "keep"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(dir, "wiki"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(dir, "wiki", "inwing")))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "raw", "v.md"), []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("raw", "keep"), filepath.Join(dir, "indir")))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "wiki", "exists.md"), []byte("original"), 0o644))
-	require.NoError(t, os.Symlink("nowhere.md", filepath.Join(dir, "wiki", "dangling.md")))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	assert.ErrorIs(t, b.CreateRegular("wiki/inwing/facts/n.md", []byte("x")), ErrNotRegular)
-	_, err = os.Stat(filepath.Join(dir, "raw", "facts"))
-	assert.True(t, os.IsNotExist(err), "nothing created through the in-brain link")
-	assert.ErrorIs(t, b.CreateRegular("indir/../v.md", []byte("x")), ErrNotRegular)
-	got, _ := os.ReadFile(filepath.Join(dir, "raw", "v.md"))
-	assert.Equal(t, "untouched", string(got))
-
-	assert.ErrorIs(t, b.CreateRegular("wiki/exists.md", []byte("x")), fs.ErrExist)
-	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "exists.md"))
-	assert.Equal(t, "original", string(got))
-	assert.ErrorIs(t, b.CreateRegular("wiki/dangling.md", []byte("x")), fs.ErrExist)
-	_, err = os.Stat(filepath.Join(dir, "wiki", "nowhere.md"))
-	assert.True(t, os.IsNotExist(err), "nothing created at the dangling link's target")
-
-	require.NoError(t, b.CreateRegular("wiki/new/facts/n.md", []byte("one")), "positive control: create with missing parents")
-	got, _ = os.ReadFile(filepath.Join(dir, "wiki", "new", "facts", "n.md"))
-	assert.Equal(t, "one", string(got))
-}

ingestion/internal/brainfs/brainfstest/brainfstest.go

@@ -1,15 +1,12 @@
 // Package brainfstest is the shared harness for hyperguild#157's swap-race
-// tests: it keeps swapping a regular note, a symlink to a sentinel target file
+// tests: it keeps swapping a regular note, a symlink to an outside file, or a
-// (outside the brain, or inside it for hyperguild#171), or a FIFO (with a
+// FIFO (with a writer held open) into a path while a reader under test loops.
-// writer held open) into a path while a reader under test loops.
+// It observes two things: no sentinel byte from the outside file reaches the
-// It observes two things, over a sampled window only: no sentinel byte from
+// reader's output, and the reader returns within a timeout. It does not cover
-// the target reaches the reader's output, and the reader returns within a
-// timeout. It does not cover
 // hard links, other paths into the reader, or races it does not generate.
 package brainfstest
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -20,50 +17,32 @@ import (
 	"time"
 )
 
-// Sentinel marks the target file's contents.
+// Sentinel marks the outside file's contents.
 const Sentinel = "zqbrainfssentinelonefiftyseven"
 
-// outsideContent carries Sentinel in every field a reader might extract: the
-// frontmatter title and aliases, a heading, a wikilink and the body.
-const outsideContent = "---\ntitle: " + Sentinel + "\naliases:\n  - " + Sentinel + "\n---\n# " + Sentinel +
-	"\n\n" + Sentinel + " [[" + Sentinel + "]]\n"
-
 // Outside writes a file outside any brain dir containing Sentinel.
-func Outside(t testing.TB) string {
+func Outside(t *testing.T) string {
 	t.Helper()
 	p := filepath.Join(t.TempDir(), "secret.md")
-	if err := os.WriteFile(p, []byte(outsideContent), 0o644); err != nil {
+	if err := os.WriteFile(p, []byte("# secret\n\n"+Sentinel), 0o644); err != nil {
 		t.Fatal(err)
 	}
 	return p
 }
 
-var swapSeq atomic.Int64
-
 // StartSwap renames, in a loop, a regular note (content inside) and either
 // a symlink to outside or a FIFO into path, until the test ends. FIFOs get a
 // writer held open until the swapper exits, so a reader that skips the
 // handle check parks forever instead of reading EOF. The swapper is stopped
-// and awaited before t.TempDir cleanup. It returns the number of symlinks
+// and awaited before t.TempDir cleanup.
-// or FIFOs actually renamed into path so far, so a caller can tell a race
+func StartSwap(t *testing.T, path, inside, outside string, fifo bool) {
-// that ran from one whose every swap failed (hyperguild#177).
-func StartSwap(t testing.TB, path, inside, outside string, fifo bool) *atomic.Int64 {
 	t.Helper()
-	var swaps atomic.Int64
 	var stop atomic.Bool
 	var wg sync.WaitGroup
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
-		// A name of its own: swappers on one path share a test, and one
+		tmp := path + ".swap"
-		// opening another's FIFO for write would block forever.
-		tmp := fmt.Sprintf("%s.swap%d", path, swapSeq.Add(1))
-		// A relative link: os.Root refuses every absolute link on its own, so
-		// an absolute in-brain target would test nothing.
-		link := outside
-		if rel, err := filepath.Rel(filepath.Dir(path), outside); err == nil {
-			link = rel
-		}
 		var writers []*os.File
 		defer func() {
 			for _, w := range writers {
@@ -72,84 +51,35 @@ func StartSwap(t testing.TB, path, inside, outside string, fifo bool) *atomic.In
 		}()
 		for i := 0; !stop.Load(); i++ {
 			_ = os.Remove(tmp)
-			var made error
 			switch {
 			case i%2 == 0:
 				_ = os.WriteFile(tmp, []byte(inside), 0o644)
 			case fifo:
-				if made = syscall.Mkfifo(tmp, 0o644); made == nil {
+				if err := syscall.Mkfifo(tmp, 0o644); err == nil {
 					if w, err := os.OpenFile(tmp, os.O_RDWR, 0); err == nil {
 						writers = append(writers, w)
 					}
 				}
 			default:
-				made = os.Symlink(link, tmp)
+				_ = os.Symlink(outside, tmp)
-			}
-			if err := os.Rename(tmp, path); err == nil && made == nil && i%2 == 1 {
-				swaps.Add(1)
 			}
+			_ = os.Rename(tmp, path)
 		}
 	}()
 	t.Cleanup(func() { stop.Store(true); wg.Wait() })
-	return &swaps
-}
-
-// WriteSentinelAt writes a file carrying Sentinel at p (creating its
-// directory), for an in-brain symlink target.
-func WriteSentinelAt(t *testing.T, p string) string {
-	t.Helper()
-	if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
-		t.Fatal(err)
-	}
-	if err := os.WriteFile(p, []byte(outsideContent), 0o644); err != nil {
-		t.Fatal(err)
-	}
-	return p
 }
 
 // AssertNoLeak loops read for d while a symlink swapper runs on path, and
-// fails if any output contains Sentinel. The symlink points outside the
+// fails if any output contains Sentinel.
-// brain; os.Root refuses that on its own, so pair it with AssertNoLeakFrom
-// and an in-brain target.
 func AssertNoLeak(t *testing.T, path, inside string, d time.Duration, read func() string) {
 	t.Helper()
-	AssertNoLeakFrom(t, path, inside, Outside(t), d, read)
+	StartSwap(t, path, inside, Outside(t), false)
-}
+	leaks, iters := 0, 0
-
-// InsideMarker must appear in the inside note's content and in read's
-// output whenever read saw that note: the floor below counts such reads.
-const InsideMarker = "inside"
-
-// AssertNoLeakFrom is AssertNoLeak with the symlink pointing at target, e.g.
-// a file elsewhere in the brain written with WriteSentinelAt.
-//
-// Beyond "no Sentinel in any output" it sets two floors, because without
-// them the assertion passes when nothing was tested (hyperguild#177): at
-// least one symlink must have been swapped into path, and at least one read
-// must have returned InsideMarker (a reader that always errors returns
-// nothing, and so never leaks).
-func AssertNoLeakFrom(t testing.TB, path, inside, target string, d time.Duration, read func() string) {
-	t.Helper()
-	if !strings.Contains(inside, InsideMarker) {
-		t.Fatalf("inside content must contain %q", InsideMarker)
-	}
-	swaps := StartSwap(t, path, inside, target, false)
-	leaks, iters, insideReads := 0, 0, 0
 	for deadline := time.Now().Add(d); time.Now().Before(deadline); iters++ {
-		out := read()
+		leaks += strings.Count(read(), Sentinel)
-		leaks += strings.Count(out, Sentinel)
-		if strings.Contains(out, InsideMarker) {
-			insideReads++
-		}
 	}
 	if leaks > 0 {
-		t.Fatalf("symlink target %s leaked %d times in %d iterations", target, leaks, iters)
+		t.Fatalf("outside file leaked %d times in %d iterations", leaks, iters)
-	}
-	if n := swaps.Load(); n == 0 {
-		t.Fatalf("no symlink was swapped into %s in %d iterations: the race did not run", path, iters)
-	}
-	if insideReads == 0 {
-		t.Fatalf("no read in %d iterations returned the inside note (%q): the reader read nothing", iters, InsideMarker)
 	}
 }
 

ingestion/internal/brainfs/brainfstest/brainfstest_test.go

@@ -1,79 +0,0 @@
-package brainfstest
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-	"runtime"
-	"syscall"
-	"testing"
-	"time"
-)
-
-// recordingTB stands in for the test under AssertNoLeakFrom so a fatal
-// there can be observed instead of failing this test. Fatalf ends the
-// calling goroutine the way testing.T does.
-type recordingTB struct {
-	testing.TB
-	failed bool
-	msg    string
-}
-
-func (r *recordingTB) Fatalf(format string, args ...any) {
-	r.failed, r.msg = true, fmt.Sprintf(format, args...)
-	runtime.Goexit()
-}
-
-func runAssert(t *testing.T, path, target string, read func() string) *recordingTB {
-	t.Helper()
-	r := &recordingTB{TB: t}
-	done := make(chan struct{})
-	go func() {
-		defer close(done)
-		AssertNoLeakFrom(r, path, "inside", target, 200*time.Millisecond, read)
-	}()
-	<-done
-	return r
-}
-
-// hyperguild#177: with every swap failing, no leak can occur, so the leak
-// assertion passed without testing anything.
-func TestAssertNoLeakFromFailsWhenNoSymlinkSwapSucceeds(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "missing-dir", "r.md")
-	r := runAssert(t, path, Outside(t), func() string { return "inside" })
-	if !r.failed {
-		t.Fatal("AssertNoLeakFrom passed with zero successful symlink swaps")
-	}
-}
-
-// hyperguild#177: a reader that always errors returns nothing, so it never
-// leaks either.
-func TestAssertNoLeakFromFailsWhenNoReadReturnsTheInsideNote(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "r.md")
-	r := runAssert(t, path, Outside(t), func() string { return "" })
-	if !r.failed {
-		t.Fatal("AssertNoLeakFrom passed with zero reads returning the inside note")
-	}
-}
-
-// Positive control: a reader that refuses symlinks and reads regular files
-// passes, so the floors do not fail a working reader.
-func TestAssertNoLeakFromPassesAReaderThatRefusesSymlinks(t *testing.T) {
-	path := filepath.Join(t.TempDir(), "r.md")
-	read := func() string {
-		f, err := os.OpenFile(path, os.O_RDONLY|noFollow, 0)
-		if err != nil {
-			return ""
-		}
-		defer func() { _ = f.Close() }()
-		b := make([]byte, 64)
-		n, _ := f.Read(b)
-		return string(b[:n])
-	}
-	r := runAssert(t, path, Outside(t), read)
-	if r.failed {
-		t.Fatalf("a symlink-refusing reader failed: %s", r.msg)
-	}
-}
-
-const noFollow = syscall.O_NOFOLLOW

ingestion/internal/classification/classification.go

@@ -16,10 +16,9 @@
 package classification
 
 import (
-	"errors"
 	"fmt"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
+	"os"
-	"io/fs"
+	"path/filepath"
 	"strings"
 
 	"gopkg.in/yaml.v3"
@@ -111,20 +110,9 @@ type rawConfig struct {
 func Load(brainDir string) (*Config, error) {
 	cfg := &Config{wings: map[string]Level{}, repos: map[string]Level{}}
 
-	// Read through the brain root, regular files only (hyperguild#157): a
+	data, err := os.ReadFile(filepath.Join(brainDir, "classification.yaml"))
-	// symlinked or special file is not trusted as the config, which is a hard
-	// error like a malformed one.
-	bfs, err := brainfs.Open(brainDir)
-	if errors.Is(err, fs.ErrNotExist) {
-		return cfg, nil
-	}
 	if err != nil {
-		return nil, fmt.Errorf("open brain: %w", err)
+		if os.IsNotExist(err) {
-	}
-	defer func() { _ = bfs.Close() }()
-	data, err := bfs.ReadRegular("classification.yaml")
-	if err != nil {
-		if errors.Is(err, fs.ErrNotExist) {
 			return cfg, nil
 		}
 		return nil, fmt.Errorf("read classification.yaml: %w", err)

ingestion/internal/classification/root_test.go

@@ -1,46 +0,0 @@
-package classification
-
-import (
-	"os"
-	"path/filepath"
-	"syscall"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// hyperguild#157 slice 6: Load read classification.yaml with os.ReadFile. It
-// sets the I1 sovereignty levels; a symlinked file must not be trusted as the
-// config (a hard error, as for a malformed file), and a FIFO must not hang
-// startup.
-func TestLoadRefusesASymlinkedOrFIFOClassificationFile(t *testing.T) {
-	ok := t.TempDir()
-	require.NoError(t, os.WriteFile(filepath.Join(ok, "classification.yaml"), []byte("wings:\n  w: confidential\n"), 0o644))
-	_, err := Load(ok)
-	require.NoError(t, err, "positive control")
-
-	linked := t.TempDir()
-	require.NoError(t, os.WriteFile(filepath.Join(linked, "real.yaml"), []byte("wings:\n  w: public\n"), 0o644))
-	require.NoError(t, os.Symlink("real.yaml", filepath.Join(linked, "classification.yaml")))
-	_, err = Load(linked)
-	assert.Error(t, err, "an in-brain symlink is not trusted as the config")
-
-	fifo := t.TempDir()
-	require.NoError(t, syscall.Mkfifo(filepath.Join(fifo, "classification.yaml"), 0o644))
-	w, err := os.OpenFile(filepath.Join(fifo, "classification.yaml"), os.O_RDWR, 0)
-	require.NoError(t, err)
-	defer func() { _ = w.Close() }()
-	done := make(chan error, 1)
-	go func() { _, err := Load(fifo); done <- err }()
-	select {
-	case err := <-done:
-		assert.Error(t, err)
-	case <-time.After(3 * time.Second):
-		t.Fatal("Load hung on a FIFO")
-	}
-
-	_, err = Load(t.TempDir())
-	assert.NoError(t, err, "an absent file is still not an error")
-}

ingestion/internal/graphsync/graphsync.go

@@ -12,14 +12,10 @@ package graphsync
 
 import (
 	"context"
-	"errors"
 	"fmt"
-	"io/fs"
+	"os"
-	"path"
 	"path/filepath"
-	"strings"
 
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/graph"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/graphstore"
 )
@@ -50,25 +46,8 @@ func IndexDoc(ctx context.Context, store Store, brainDir, relPath string) error
 	if relPath == "" {
 		return nil
 	}
-	// Callers pass caller-supplied paths (brain_tunnel, brain_update): index
+	abs := filepath.Join(brainDir, filepath.FromSlash(relPath))
-	// only a clean path under wiki/ or knowledge/.
+	content, err := os.ReadFile(abs)
-	if path.Clean(relPath) != relPath || !filepath.IsLocal(relPath) ||
-		(!strings.HasPrefix(relPath, "wiki/") && !strings.HasPrefix(relPath, "knowledge/")) {
-		return fmt.Errorf("index %q: not a clean wiki/ or knowledge/ path", relPath)
-	}
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	return indexDoc(ctx, store, bfs, relPath)
-}
-
-// indexDoc reads relPath through the brain root, regular files only
-// (hyperguild#157): the brain is a Syncthing folder, and os.ReadFile
-// followed a synced symlink into the graph and blocked on a FIFO.
-func indexDoc(ctx context.Context, store Store, bfs *brainfs.Brain, relPath string) error {
-	content, err := bfs.ReadRegular(relPath)
 	if err != nil {
 		return fmt.Errorf("read %q: %w", relPath, err)
 	}
@@ -98,34 +77,33 @@ func BackfillFromBrainDir(ctx context.Context, store Store, brainDir string) (in
 	if store == nil {
 		return 0, nil
 	}
-	bfs, err := brainfs.Open(brainDir)
+	roots := []string{"wiki", "knowledge"}
-	if err != nil {
+	for _, root := range roots {
-		return 0, fmt.Errorf("open brain: %w", err)
+		base := filepath.Join(brainDir, root)
-	}
+		if _, err := os.Stat(base); os.IsNotExist(err) {
-	defer func() { _ = bfs.Close() }()
-	for _, root := range []string{"wiki", "knowledge"} {
-		if _, err := bfs.Lstat(root); errors.Is(err, fs.ErrNotExist) {
 			continue
 		}
-		// Any walk error, including a root that is a symlink, aborts.
+		err := filepath.WalkDir(base, func(path string, d os.DirEntry, walkErr error) error {
-		var walkErr error
+			if walkErr != nil {
-		err := bfs.WalkRegular(root, func(rel string) error {
+				return walkErr
-			if path.Ext(rel) != ".md" {
+			}
+			if d.IsDir() {
 				return nil
 			}
-			if err := indexDoc(ctx, store, bfs, rel); err != nil {
+			if filepath.Ext(path) != ".md" {
+				return nil
+			}
+			rel, relErr := filepath.Rel(brainDir, path)
+			if relErr != nil {
+				return fmt.Errorf("rel %q: %w", path, relErr)
+			}
+			rel = filepath.ToSlash(rel)
+			if err := IndexDoc(ctx, store, brainDir, rel); err != nil {
 				return fmt.Errorf("index %q: %w", rel, err)
 			}
 			indexed++
 			return nil
-		}, func(rel string, err error) {
-			if walkErr == nil {
-				walkErr = fmt.Errorf("%s: %w", rel, err)
-			}
 		})
-		if err == nil {
-			err = walkErr
-		}
 		if err != nil {
 			return indexed, fmt.Errorf("walk %s: %w", root, err)
 		}

ingestion/internal/graphsync/graphsync_root_test.go

@@ -1,92 +0,0 @@
-package graphsync
-
-import (
-	"context"
-	"fmt"
-	"os"
-	"path/filepath"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
-)
-
-func (f *fakeStore) dump() string {
-	f.mu.Lock()
-	defer f.mu.Unlock()
-	return fmt.Sprintf("%+v %+v", f.upserts, f.replaces)
-}
-
-// hyperguild#157 slice 4: IndexDoc and BackfillFromBrainDir read notes with
-// os.ReadFile, so a symlinked note put the target's title and wikilinks into
-// the graph, and a FIFO hung the read.
-func TestIndexDocRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
-	brain := t.TempDir()
-	facts := filepath.Join(brain, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: zqinside\n---\nbody [[other]]\n"), 0o644))
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "leak.md")))
-
-	store := newFakeStore()
-	require.NoError(t, IndexDoc(context.Background(), store, brain, "wiki/w/facts/ok.md"))
-	assert.Contains(t, store.dump(), "zqinside", "positive control: a regular note is indexed")
-	assert.Error(t, IndexDoc(context.Background(), store, brain, "wiki/w/facts/leak.md"))
-	// A link to a file elsewhere in the brain: os.Root allows it, only the
-	// regular-file check refuses it.
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	assert.Error(t, IndexDoc(context.Background(), store, brain, "wiki/w/facts/inlink.md"))
-	assert.NotContains(t, store.dump(), brainfstest.Sentinel)
-
-	p := filepath.Join(facts, "r.md")
-	read := func() string {
-		s := newFakeStore()
-		_ = IndexDoc(context.Background(), s, brain, "wiki/w/facts/r.md")
-		return s.dump()
-	}
-	brainfstest.AssertNoLeak(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, read)
-	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: zqinside\n---\n", inBrain, 1500*time.Millisecond, read)
-	brainfstest.AssertNoHang(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
-}
-
-func TestBackfillSkipsSymlinkedNotesAndAbortsOnASymlinkedRoot(t *testing.T) {
-	brain := t.TempDir()
-	facts := filepath.Join(brain, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: zqinside\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "leak.md")))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "raw"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "raw", "r.md"), []byte("---\ntitle: zqrawonly\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "r.md"), filepath.Join(facts, "inlink.md")))
-	require.NoError(t, os.Symlink(".", filepath.Join(brain, "knowledge")))
-
-	store := newFakeStore()
-	_, err := BackfillFromBrainDir(context.Background(), store, brain)
-	assert.Error(t, err, "a symlinked root aborts the backfill")
-	assert.NotContains(t, store.dump(), brainfstest.Sentinel)
-	assert.NotContains(t, store.dump(), "zqrawonly")
-
-	require.NoError(t, os.Remove(filepath.Join(brain, "knowledge")))
-	store = newFakeStore()
-	n, err := BackfillFromBrainDir(context.Background(), store, brain)
-	require.NoError(t, err)
-	assert.Equal(t, 1, n, "only the regular note is indexed")
-	assert.Contains(t, store.dump(), "zqinside")
-	assert.NotContains(t, store.dump(), brainfstest.Sentinel)
-}
-
-// IndexDoc gets caller-supplied paths (brain_tunnel, brain_update): only a
-// clean path under wiki/ or knowledge/ is indexed.
-func TestIndexDocRefusesPathsOutsideWikiAndKnowledgeAndUncleanPaths(t *testing.T) {
-	brain := t.TempDir()
-	brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "secret.md"))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki", "w"), 0o755))
-	for _, p := range []string{"raw/secret.md", "wiki/w/../../raw/secret.md", "./raw/secret.md", "/raw/secret.md"} {
-		store := newFakeStore()
-		assert.Error(t, IndexDoc(context.Background(), store, brain, p), p)
-		assert.NotContains(t, store.dump(), brainfstest.Sentinel, p)
-	}
-}

ingestion/internal/mcp/readexcerpt_root_test.go

@@ -21,11 +21,6 @@ func TestReadExcerptRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
 	require.NoError(t, os.MkdirAll(facts, 0o755))
 	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "leak.md")))
 	assert.NotContains(t, readExcerpt(brain, "wiki/w/facts/leak.md", 500), brainfstest.Sentinel)
-	// A link to a file elsewhere in the brain: os.Root allows it, only the
-	// regular-file check refuses it (hyperguild#171).
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	assert.NotContains(t, readExcerpt(brain, "wiki/w/facts/inlink.md", 500), brainfstest.Sentinel)
 
 	p := filepath.Join(facts, "r.md")
 	require.NoError(t, os.WriteFile(p, []byte("---\nx: y\n---\ninside"), 0o644))
@@ -33,9 +28,6 @@ func TestReadExcerptRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
 	brainfstest.AssertNoLeak(t, p, "---\nx: y\n---\ninside", 1500*time.Millisecond, func() string {
 		return readExcerpt(brain, "wiki/w/facts/r.md", 500)
 	})
-	brainfstest.AssertNoLeakFrom(t, p, "---\nx: y\n---\ninside", inBrain, 1500*time.Millisecond, func() string {
-		return readExcerpt(brain, "wiki/w/facts/r.md", 500)
-	})
 	brainfstest.AssertNoHang(t, p, "---\nx: y\n---\ninside", 1500*time.Millisecond, 6*time.Second, func() {
 		_ = readExcerpt(brain, "wiki/w/facts/r.md", 500)
 	})

ingestion/internal/notes/edit_redirect_test.go

@@ -1,36 +0,0 @@
-package notes
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// hyperguild#188/#173: brain_edit's atomic rename must not be redirected by
-// a symlinked directory inside the brain.
-func TestEditRefusesANoteBehindASymlinkedDirectory(t *testing.T) {
-	b := t.TempDir()
-	// Edit refuses a tree that is not the sync source before any path
-	// check, so the test needs a .git to reach the symlink refusal.
-	require.NoError(t, os.MkdirAll(filepath.Join(b, ".git"), 0o755))
-	victim := filepath.Join(b, "raw", "facts", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("old text\n"), 0o644))
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w"), 0o755))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(b, "wiki", "w", "alias")))
-	_, err := Edit(b, "wiki/w/alias/v.md", "old text", "new text", ScopeNotes)
-	assert.Error(t, err)
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "old text\n", string(got))
-
-	real := filepath.Join(b, "wiki", "w", "facts", "r.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(real), 0o755))
-	require.NoError(t, os.WriteFile(real, []byte("old text\n"), 0o644))
-	_, err = Edit(b, "wiki/w/facts/r.md", "old text", "new text", ScopeNotes)
-	require.NoError(t, err, "positive control: a note in a real directory is edited")
-	got, _ = os.ReadFile(real)
-	assert.Equal(t, "new text\n", string(got))
-}

ingestion/internal/notes/read_root_test.go

@@ -38,31 +38,3 @@ func TestReadScopedRefusesANoteOverMaxNoteBytes(t *testing.T) {
 	_, err := ReadScoped(brain, "wiki/w/facts/big.md", ScopeNotes)
 	assert.ErrorIs(t, err, ErrTooLarge)
 }
-
-// hyperguild#171 (review of #172, finding 1): os.Root alone refuses links that
-// leave the brain, so the outside-target race above stays green for a reader
-// that skips brainfs's Lstat and SameFile checks. An in-brain target (raw/,
-// outside ScopeNotes) is what tells them apart.
-func TestReadScopedDoesNotReturnAnInBrainSymlinkTargetStaticallyOrDuringASampledSwapRace(t *testing.T) {
-	brain := t.TempDir()
-	facts := filepath.Join(brain, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	target := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	b, err := ReadScoped(brain, "wiki/w/facts/inlink.md", ScopeNotes)
-	assert.Error(t, err, "static in-brain link")
-	assert.NotContains(t, string(b), brainfstest.Sentinel, "static in-brain link")
-
-	p := filepath.Join(facts, "r.md")
-	require.NoError(t, os.WriteFile(p, []byte("inside"), 0o644))
-	b, err = ReadScoped(brain, "wiki/w/facts/r.md", ScopeNotes)
-	require.NoError(t, err)
-	assert.Equal(t, "inside", string(b), "positive control: a regular note reads")
-
-	read := func() string {
-		b, _ := ReadScoped(brain, "wiki/w/facts/r.md", ScopeNotes)
-		return string(b)
-	}
-	brainfstest.AssertNoLeakFrom(t, p, "inside", target, 1500*time.Millisecond, read)
-}

ingestion/internal/pipeline/backfill.go

@@ -3,10 +3,7 @@ package pipeline
 
 import (
 	"context"
-	"errors"
 	"fmt"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
-	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -26,16 +23,10 @@ func BackfillRefs(ctx context.Context, brainDir string) (int, error) {
 		return 0, fmt.Errorf("load inventory: %w", err)
 	}
 
-	// Listed and read through the brain root, regular files only
+	sourcesDir := filepath.Join(brainDir, "wiki", "sources")
-	// (hyperguild#157).
+	entries, err := os.ReadDir(sourcesDir)
-	bfs, err := brainfs.Open(brainDir)
 	if err != nil {
-		return 0, fmt.Errorf("open brain: %w", err)
+		if os.IsNotExist(err) {
-	}
-	defer func() { _ = bfs.Close() }()
-	names, err := bfs.ReadDirRegular("wiki/sources")
-	if err != nil {
-		if errors.Is(err, fs.ErrNotExist) {
 			return 0, nil
 		}
 		return 0, fmt.Errorf("read sources dir: %w", err)
@@ -46,20 +37,20 @@ func BackfillRefs(ctx context.Context, brainDir string) (int, error) {
 	// get both refs merged before a single write.
 	pending := make(map[string]wiki.Page)
 
-	for _, name := range names {
+	for _, e := range entries {
 		if ctx.Err() != nil {
 			return 0, ctx.Err()
 		}
-		if !strings.HasSuffix(name, ".md") {
+		if e.IsDir() || !strings.HasSuffix(e.Name(), ".md") {
 			continue
 		}
 
-		b, err := bfs.ReadRegular("wiki/sources/" + name)
+		b, err := os.ReadFile(filepath.Join(sourcesDir, e.Name()))
 		if err != nil {
 			continue
 		}
 		sourceContent := string(b)
-		sourceSlug := strings.TrimSuffix(name, ".md")
+		sourceSlug := strings.TrimSuffix(e.Name(), ".md")
 		sourceTitle := extractTitle(sourceContent)
 		if sourceTitle == "" {
 			sourceTitle = sourceSlug
@@ -79,7 +70,7 @@ func BackfillRefs(ctx context.Context, brainDir string) (int, error) {
 			// Start from already-accumulated version if we've seen this page.
 			page, seen := pending[relPath]
 			if !seen {
-				raw, err := bfs.ReadRegular(relPath)
+				raw, err := os.ReadFile(filepath.Join(brainDir, filepath.FromSlash(relPath)))
 				if err != nil {
 					continue
 				}

ingestion/internal/pipeline/pipeline.go

@@ -5,10 +5,7 @@ import (
 	"context"
 	"crypto/sha256"
 	"encoding/hex"
-	"errors"
 	"fmt"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
-	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
@@ -132,7 +129,7 @@ func buildAndWrite(ctx context.Context, rawPages []RawPage, sourceSlug, date, br
 			if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
 				return Result{}, fmt.Errorf("mkdir for %s: %w", page.Path, err)
 			}
-			content, conflicts, err := reviseOrCreate(brainDir, page)
+			content, conflicts, err := reviseOrCreate(dest, page)
 			if err != nil {
 				return Result{}, err
 			}
@@ -191,27 +188,14 @@ func hashBody(content string) string {
 
 // readSourcePage returns the full on-disk content of the source page at
 // wiki/sources/<sourceSlug>.md, or "" when it doesn't exist yet.
-// It reads through the brain root, regular files only (hyperguild#157): the
-// content goes into the LLM prompt.
 func readSourcePage(brainDir, sourceSlug string) string {
-	raw, err := readBrainFile(brainDir, "wiki/sources/"+sourceSlug+".md")
+	raw, err := os.ReadFile(filepath.Join(brainDir, "wiki", "sources", sourceSlug+".md"))
 	if err != nil {
 		return ""
 	}
 	return string(raw)
 }
 
-// readBrainFile reads one brain-relative file through the brain root,
-// regular files only (hyperguild#157).
-func readBrainFile(brainDir, rel string) ([]byte, error) {
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return nil, err
-	}
-	defer func() { _ = bfs.Close() }()
-	return bfs.ReadRegular(rel)
-}
-
 // storedSourceHash reads source_hash from the source page a previous ingest
 // wrote, or "" when there is no such page or no such field.
 //
@@ -246,10 +230,10 @@ func storedSourceHash(brainDir, sourceSlug string) string {
 // its first-ingest date on a revised page. Left deliberately — the alternative
 // is this function editing frontmatter it does not own, and no lint reads that
 // field today.
-func reviseOrCreate(brainDir string, page wiki.Page) (string, []string, error) {
+func reviseOrCreate(dest string, page wiki.Page) (string, []string, error) {
-	existing, err := readBrainFile(brainDir, page.Path)
+	existing, err := os.ReadFile(dest)
 	switch {
-	case errors.Is(err, fs.ErrNotExist):
+	case os.IsNotExist(err):
 		return page.Content, nil, nil
 	case err != nil:
 		return "", nil, fmt.Errorf("read existing %s: %w", page.Path, err)
@@ -283,7 +267,7 @@ See brain/schema.md for the full schema.
 `
 
 func loadSchema(brainDir string) string {
-	b, err := readBrainFile(brainDir, "schema.md")
+	b, err := os.ReadFile(filepath.Join(brainDir, "schema.md"))
 	if err != nil {
 		return defaultSchema
 	}

ingestion/internal/pipeline/refs.go

@@ -2,6 +2,7 @@
 package pipeline
 
 import (
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -52,7 +53,8 @@ func injectSourceRefs(pages []wiki.Page, inventory map[wiki.PageType][]wiki.Entr
 		if !ok {
 			continue
 		}
-		b, err := readBrainFile(brainDir, "wiki/"+string(pt)+"/"+slug+".md")
+		diskPath := filepath.Join(brainDir, "wiki", string(pt), slug+".md")
+		b, err := os.ReadFile(diskPath)
 		if err != nil {
 			continue
 		}

ingestion/internal/pipeline/root_test.go

@@ -1,167 +0,0 @@
-package pipeline
-
-import (
-	"context"
-	"fmt"
-	"io"
-	"os"
-	"path/filepath"
-	"syscall"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/wiki"
-)
-
-// hyperguild#157 slice 6: the pipeline read the source page, schema.md, the
-// pages it revises and the pages it adds source refs to with os.ReadFile, so
-// a symlinked file's content reached the LLM prompt and the written pages,
-// and a FIFO hung the ingest.
-
-func mkdirs(t *testing.T, brain string, dirs ...string) {
-	t.Helper()
-	for _, d := range dirs {
-		require.NoError(t, os.MkdirAll(filepath.Join(brain, filepath.FromSlash(d)), 0o755))
-	}
-}
-
-func TestReadSourcePageAndSchemaRefuseSymlinksAndSurviveSwapRaces(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/sources")
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "sources", "ok.md"), []byte("zqinside source"), 0o644))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "schema.md"), []byte("zqinside schema"), 0o644))
-	assert.Equal(t, "zqinside source", readSourcePage(brain, "ok"), "positive control")
-	assert.Equal(t, "zqinside schema", loadSchema(brain), "positive control")
-
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(brain, "wiki", "sources", "out.md")))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "s.md"), filepath.Join(brain, "wiki", "sources", "in.md")))
-	assert.NotContains(t, readSourcePage(brain, "out"), brainfstest.Sentinel)
-	assert.NotContains(t, readSourcePage(brain, "in"), brainfstest.Sentinel)
-	assert.NotContains(t, storedSourceHash(brain, "in"), brainfstest.Sentinel)
-
-	src := filepath.Join(brain, "wiki", "sources", "r.md")
-	read := func() string { return readSourcePage(brain, "r") }
-	brainfstest.AssertNoLeak(t, src, "zqinside", 1500*time.Millisecond, read)
-	brainfstest.AssertNoLeakFrom(t, src, "zqinside", inBrain, 1500*time.Millisecond, read)
-	brainfstest.AssertNoHang(t, src, "zqinside", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
-
-	schema := filepath.Join(brain, "schema.md")
-	rs := func() string { return loadSchema(brain) }
-	brainfstest.AssertNoLeakFrom(t, schema, "zqinside schema", inBrain, 1500*time.Millisecond, rs)
-	brainfstest.AssertNoHang(t, schema, "zqinside schema", 1500*time.Millisecond, 6*time.Second, func() { _ = rs() })
-}
-
-func TestReviseOrCreateRefusesASymlinkedExistingPage(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/concepts")
-	brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "s.md"), filepath.Join(brain, "wiki", "concepts", "c.md")))
-	page := wiki.Page{Path: "wiki/concepts/c.md", Content: "---\ntitle: C\n---\nnew\n"}
-	out, _, err := reviseOrCreate(brain, page)
-	assert.Error(t, err)
-	assert.NotContains(t, out, brainfstest.Sentinel)
-
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "concepts", "d.md"), []byte("---\ntitle: D\n---\nzqold\n"), 0o644))
-	out, _, err = reviseOrCreate(brain, wiki.Page{Path: "wiki/concepts/d.md", Content: "---\ntitle: D\n---\nnew\n"})
-	require.NoError(t, err)
-	assert.Contains(t, out, "zqold", "positive control: the existing page is read")
-	out, _, err = reviseOrCreate(brain, wiki.Page{Path: "wiki/concepts/new.md", Content: "fresh"})
-	require.NoError(t, err)
-	assert.Equal(t, "fresh", out, "positive control: a missing page is created")
-}
-
-func TestInjectSourceRefsDoesNotReadASymlinkedPage(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/concepts")
-	brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "s.md"), filepath.Join(brain, "wiki", "concepts", "c.md")))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "concepts", "d.md"), []byte("zqinside d"), 0o644))
-	inv := map[wiki.PageType][]wiki.Entry{wiki.PageTypeConcept: {
-		{Slug: "c", Type: wiki.PageTypeConcept}, {Slug: "d", Type: wiki.PageTypeConcept},
-	}}
-	src := wiki.Page{Path: "wiki/sources/src.md", Content: "---\ntitle: Src\n---\nsee [[c|C]] and [[d|D]]\n"}
-	out := injectSourceRefs([]wiki.Page{src}, inv, brain)
-	got := fmt.Sprintf("%+v", out)
-	assert.Contains(t, got, "zqinside d", "positive control")
-	assert.NotContains(t, got, brainfstest.Sentinel)
-}
-
-func TestBackfillRefsSkipsSymlinkedSourcesAndPages(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/sources", "wiki/concepts", "raw")
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "concepts", "real.md"), []byte("---\ntitle: R\n---\nbody\n"), 0o644))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "sources", "ok.md"), []byte("---\ntitle: zqinside\n---\n[[real|R]]\n"), 0o644))
-	// A source elsewhere in the brain whose title is the sentinel and which
-	// links the real concept with the [[slug|title]] form the pipeline follows.
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "raw", "src.md"),
-		[]byte("---\ntitle: "+brainfstest.Sentinel+"\n---\n[[real|R]]\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "src.md"), filepath.Join(brain, "wiki", "sources", "in.md")))
-	// A concept page linked by the regular source that is itself a symlink.
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "sources", "ok2.md"), []byte("---\ntitle: Two\n---\n[[lnk|L]]\n"), 0o644))
-	brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "page.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "page.md"), filepath.Join(brain, "wiki", "concepts", "lnk.md")))
-
-	_, err := BackfillRefs(context.Background(), brain)
-	require.NoError(t, err)
-	b, _ := os.ReadFile(filepath.Join(brain, "wiki", "concepts", "real.md"))
-	assert.Contains(t, string(b), "zqinside", "positive control: the regular source's ref is added")
-	assert.NotContains(t, string(b), brainfstest.Sentinel, "a symlinked source's title was written as a ref")
-	raw, _ := os.ReadFile(filepath.Join(brain, "raw", "page.md"))
-	assert.NotContains(t, string(raw), "[[ok2", "the symlinked concept page's target was rewritten")
-}
-
-// A source swapped between a regular file and a symlink to an in-brain source
-// whose title is the sentinel: the read refuses the swapped-in link, so the
-// sentinel never lands in the concept page as a ref.
-func TestBackfillRefsDoesNotWriteARefFromASourceSwappedInBehindASymlink(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/sources", "wiki/concepts", "raw")
-	realPage := filepath.Join(brain, "wiki", "concepts", "real.md")
-	target := filepath.Join(brain, "raw", "src.md")
-	require.NoError(t, os.WriteFile(target, []byte("---\ntitle: "+brainfstest.Sentinel+"\n---\n[[real|R]]\n"), 0o644))
-	src := filepath.Join(brain, "wiki", "sources", "r.md")
-	inside := "---\ntitle: zqinside\n---\n[[real|R]]\n"
-	read := func() string {
-		_ = os.WriteFile(realPage, []byte("---\ntitle: R\n---\nbody\n"), 0o644)
-		_, _ = BackfillRefs(context.Background(), brain)
-		b, _ := os.ReadFile(realPage)
-		return string(b)
-	}
-	require.NoError(t, os.WriteFile(src, []byte(inside), 0o644))
-	require.Contains(t, read(), "zqinside", "positive control")
-	brainfstest.AssertNoLeakFrom(t, src, inside, target, 1500*time.Millisecond, read)
-}
-
-// A concept page that is regular when the inventory lists it, then swapped
-// for a symlink to an in-brain file before BackfillRefs reads it: only the
-// page read's own check refuses it (a static symlink never gets this far,
-// because LoadInventory does not list it).
-func TestBackfillRefsDoesNotCopyAPageSwappedInBehindASymlink(t *testing.T) {
-	brain := t.TempDir()
-	mkdirs(t, brain, "wiki/sources", "wiki/concepts", "raw")
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "wiki", "sources", "s.md"), []byte("---\ntitle: S\n---\n[[c|C]]\n"), 0o644))
-	page := filepath.Join(brain, "wiki", "concepts", "c.md")
-	target := filepath.Join(brain, "raw", "secret.md")
-	inside := "---\ntitle: C\n---\nzqinside\n"
-	read := func() string {
-		// The write path still follows a swapped-in link (#158) and can
-		// overwrite the target, so restore it each round.
-		_ = os.WriteFile(target, []byte("---\ntitle: X\n---\n"+brainfstest.Sentinel+"\n"), 0o644)
-		_, _ = BackfillRefs(context.Background(), brain)
-		f, err := os.OpenFile(page, os.O_RDONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0)
-		if err != nil {
-			return ""
-		}
-		defer func() { _ = f.Close() }()
-		b, _ := io.ReadAll(f)
-		return string(b)
-	}
-	require.NoError(t, os.WriteFile(page, []byte(inside), 0o644))
-	require.Contains(t, read(), "[[s|S]]", "positive control: the regular page gets the source ref")
-	brainfstest.AssertNoLeakFrom(t, page, inside, target, 3*time.Second, read)
-}

ingestion/internal/provenance/provenance.go

@@ -28,6 +28,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"os"
 	"regexp"
 	"strings"
 
@@ -101,6 +102,25 @@ func Apply(content string, s Stamp) (string, error) {
 	return out, nil
 }
 
+// ApplyFile applies the stamp to the note at absPath in place.
+func ApplyFile(absPath string, s Stamp) error {
+	b, err := os.ReadFile(absPath)
+	if err != nil {
+		return fmt.Errorf("read for provenance: %w", err)
+	}
+	out, err := Apply(string(b), s)
+	if err != nil {
+		return err
+	}
+	if out == string(b) {
+		return nil
+	}
+	if err := os.WriteFile(absPath, []byte(out), 0o644); err != nil {
+		return fmt.Errorf("write provenance: %w", err)
+	}
+	return nil
+}
+
 // plainGroups keeps the provably plain key groups of a frontmatter block.
 func plainGroups(block string) string {
 	lines := strings.Split(strings.TrimSuffix(block, "\n"), "\n")

ingestion/internal/search/brainroot_test.go

@@ -12,8 +12,6 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
 )
 
 // hyperguild#157 option 1: search walked and read the brain by path, so a
@@ -95,20 +93,16 @@ func TestQueryDoesNotFollowASymlinkedWingUnderAWingAndHallRoot(t *testing.T) {
 // bypass of readOpened hung Query after 5 iterations).
 // startSwap runs swapInto until the test ends and waits for it before
 // t.TempDir's cleanup (hyperguild#162).
-// It returns the count of symlinks or FIFOs actually renamed into path
+func startSwap(t *testing.T, path, outside string, fifo bool) {
-// (hyperguild#177: a swapper whose every swap fails tests nothing).
-func startSwap(t *testing.T, path, outside string, fifo bool) *atomic.Int64 {
 	t.Helper()
 	var stop atomic.Bool
-	var swaps atomic.Int64
 	var wg sync.WaitGroup
 	wg.Add(1)
-	go func() { defer wg.Done(); swapInto(path, outside, fifo, &stop, &swaps) }()
+	go func() { defer wg.Done(); swapInto(path, outside, fifo, &stop) }()
 	t.Cleanup(func() { stop.Store(true); wg.Wait() })
-	return &swaps
 }
 
-func swapInto(path, outside string, fifo bool, stop *atomic.Bool, swaps *atomic.Int64) {
+func swapInto(path, outside string, fifo bool, stop *atomic.Bool) {
 	tmp := path + ".swap"
 	// Writers stay open until the swapper exits, so a reader parked on a
 	// FIFO stays parked (closing one would hand the reader EOF and hide the
@@ -121,46 +115,33 @@ func swapInto(path, outside string, fifo bool, stop *atomic.Bool, swaps *atomic.
 	}()
 	for i := 0; !stop.Load(); i++ {
 		_ = os.Remove(tmp)
-		var made error
 		switch {
 		case i%2 == 0:
 			_ = os.WriteFile(tmp, []byte("# r\n\nzqinside "+"zqracenote"), 0o644)
 		case fifo:
-			if made = syscall.Mkfifo(tmp, 0o644); made == nil {
+			if err := syscall.Mkfifo(tmp, 0o644); err == nil {
 				if w, err := os.OpenFile(tmp, os.O_RDWR, 0); err == nil {
 					writers = append(writers, w)
 				}
 			}
 		default:
-			made = os.Symlink(outside, tmp)
+			_ = os.Symlink(outside, tmp)
-		}
-		if err := os.Rename(tmp, path); err == nil && made == nil && i%2 == 1 {
-			swaps.Add(1)
 		}
+		_ = os.Rename(tmp, path)
 	}
 }
 
 func TestQueryLeaksNothingUnderASymlinkSwapRace(t *testing.T) {
 	brain, facts, outside := searchBrain(t)
-	swaps := startSwap(t, filepath.Join(facts, "r.md"), outside, false)
+	startSwap(t, filepath.Join(facts, "r.md"), outside, false)
-	leaks, iters, insideReads := 0, 0, 0
+	leaks, iters := 0, 0
 	for deadline := time.Now().Add(1500 * time.Millisecond); time.Now().Before(deadline); iters++ {
-		rs, err := Query(brain, QueryOptions{Query: sentinel157, Limit: 10})
+		rs, _ := Query(brain, QueryOptions{Query: sentinel157, Limit: 10})
-		require.NoError(t, err)
 		leaks += leaked(rs)
-		// Positive control (hyperguild#177): a Query that always errors
-		// returns nothing and so never leaks.
-		rs, err = Query(brain, QueryOptions{Query: "zqracenote", Limit: 10})
-		require.NoError(t, err)
-		if len(rs) > 0 {
-			insideReads++
-		}
 	}
 	if leaks > 0 {
 		t.Fatalf("outside file leaked %d times in %d iterations", leaks, iters)
 	}
-	require.Positive(t, swaps.Load(), "no symlink was swapped in: the race did not run")
-	require.Positive(t, insideReads, "no Query returned the inside note")
 }
 
 func TestQueryDoesNotHangUnderAFIFOSwapRace(t *testing.T) {
@@ -191,49 +172,3 @@ func TestHydrateRefusesASymlink(t *testing.T) {
 	assert.Error(t, err)
 	assert.NotContains(t, r.Excerpt, sentinel157)
 }
-
-// hyperguild#171: os.Root refuses links that leave the brain on its own, so
-// the outside-target cases above would stay green for a caller that read
-// without brainfs's Lstat and SameFile checks. These targets are inside the
-// brain (raw/, which is not a search root).
-func inBrainTarget(t *testing.T, brain string) string {
-	t.Helper()
-	return brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-}
-
-func TestQueryDoesNotReturnAnInBrainSymlinkTargetDuringASampledSwapRace(t *testing.T) {
-	brain, facts, _ := searchBrain(t)
-	target := inBrainTarget(t, brain)
-	read := func() string {
-		// Both terms, so the regular note is a possible hit: a reader that
-		// never returns the inside note would pass vacuously (#177 floor).
-		rs, _ := Query(brain, QueryOptions{Query: brainfstest.Sentinel + " zqinside", Limit: 10})
-		s := ""
-		for _, r := range rs {
-			s += r.Title + r.Excerpt
-		}
-		return s
-	}
-	brainfstest.AssertNoLeakFrom(t, filepath.Join(facts, "r.md"), "# r\n\nzqinside", target, 1500*time.Millisecond, read)
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	assert.NotContains(t, read(), brainfstest.Sentinel, "static in-brain link")
-}
-
-func TestHydrateRefusesAnInBrainSymlinkAndDoesNotReturnItsTargetDuringASampledSwapRace(t *testing.T) {
-	brain, facts, _ := searchBrain(t)
-	target := inBrainTarget(t, brain)
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
-	r, err := hydrate(brain, "wiki/w/facts/inlink.md")
-	assert.Error(t, err)
-	assert.NotContains(t, r.Excerpt+r.Title, brainfstest.Sentinel)
-
-	p := filepath.Join(facts, "r.md")
-	require.NoError(t, os.WriteFile(p, []byte("# r\n\nzqinside"), 0o644))
-	r, err = hydrate(brain, "wiki/w/facts/r.md")
-	require.NoError(t, err)
-	assert.Contains(t, r.Excerpt, "zqinside", "positive control: a regular note hydrates")
-	brainfstest.AssertNoLeakFrom(t, p, "# r\n\nzqinside", target, 1500*time.Millisecond, func() string {
-		r, _ := hydrate(brain, "wiki/w/facts/r.md")
-		return r.Title + r.Excerpt
-	})
-}

ingestion/internal/session/id_test.go

@@ -1,18 +1,12 @@
 package session
 
 import (
-	"errors"
-	"fmt"
 	"os"
 	"path/filepath"
-	"sync/atomic"
-	"syscall"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"golang.org/x/sys/unix"
 )
 
 // session_log passed the caller's session_id straight into
@@ -53,125 +47,3 @@ func TestReadRefusesSessionIDsThatAreNotPlainNames(t *testing.T) {
 	_, err := Read(filepath.Join(root, "sessions"), "../x")
 	assert.Error(t, err)
 }
-
-// A name that starts plainly and then climbs out with ".." is exactly what the
-// ban on "/" in the id's tail stops: filepath.Join cleans "a/../../x" to a
-// path beside the sessions dir without needing sessions/a to exist. The
-// assertion is on the refusal itself (ErrInvalidID), not on any error.
-func TestAppendRefusesAnIDThatClimbsOutAfterAPlainPrefix(t *testing.T) {
-	root := t.TempDir()
-	dir := filepath.Join(root, "sessions")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	for _, id := range []string{"a/../../escape", "a/../../../escape", "a/../b"} {
-		err := Append(dir, id, Entry{SessionID: id})
-		assert.ErrorIs(t, err, ErrInvalidID, "%q", id)
-	}
-	_, err := os.Lstat(filepath.Join(root, "escape.jsonl"))
-	assert.True(t, errors.Is(err, os.ErrNotExist), "nothing created beside the sessions dir")
-	_, err = os.Lstat(filepath.Join(dir, "b.jsonl"))
-	assert.True(t, errors.Is(err, os.ErrNotExist), "no in-dir alias created either")
-}
-
-// Append does no Lstat type check, so O_NONBLOCK is the only thing that keeps
-// a FIFO named <id>.jsonl with no reader from blocking session_log forever.
-func TestAppendReturnsPromptlyOnAFIFOLogWithNoReader(t *testing.T) {
-	dir := filepath.Join(t.TempDir(), "sessions")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	fifo := filepath.Join(dir, "s.jsonl")
-	require.NoError(t, syscall.Mkfifo(fifo, 0o644))
-	done := make(chan error, 1)
-	go func() { done <- Append(dir, "s", Entry{SessionID: "s"}) }()
-	select {
-	case err := <-done:
-		assert.Error(t, err, "a FIFO with no reader is refused, not written")
-	case <-time.After(3 * time.Second):
-		// Unblock the stuck open so the goroutine and TempDir cleanup finish.
-		if r, err := os.OpenFile(fifo, os.O_RDONLY|syscall.O_NONBLOCK, 0); err == nil {
-			defer r.Close() //nolint:errcheck
-		}
-		<-done
-		t.Fatal("Append blocked on a FIFO log with no reader")
-	}
-}
-
-// hyperguild#173: session_log followed a symlinked sessions dir.
-func TestAppendRefusesASymlinkedSessionsDir(t *testing.T) {
-	root := t.TempDir()
-	elsewhere := filepath.Join(root, "elsewhere")
-	require.NoError(t, os.MkdirAll(elsewhere, 0o755))
-	dir := filepath.Join(root, "sessions")
-	require.NoError(t, os.Symlink("elsewhere", dir))
-	assert.Error(t, Append(dir, "s", Entry{SessionID: "s"}))
-	ents, _ := os.ReadDir(elsewhere)
-	assert.Empty(t, ents, "a log was created through the symlinked dir")
-}
-
-// The sessions dir is swapped (RENAME_EXCHANGE) with a symlink to a
-// directory outside the brain while Append runs. Append opens through an
-// os.Root on the sessions dir's parent, so a swap can redirect it only
-// inside that parent (the #167 residual), never outside it.
-func TestAppendNeverCreatesALogOutsideTheParentUnderADirSwapRace(t *testing.T) {
-	brain := t.TempDir()
-	outside := t.TempDir()
-	dir := filepath.Join(brain, "sessions")
-	other := filepath.Join(brain, "sessions.link")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	require.NoError(t, os.Symlink(outside, other))
-	var stop atomic.Bool
-	done := make(chan struct{})
-	go func() {
-		defer close(done)
-		for !stop.Load() {
-			_ = unix.Renameat2(unix.AT_FDCWD, dir, unix.AT_FDCWD, other, unix.RENAME_EXCHANGE)
-		}
-	}()
-	ok := 0
-	for i := 0; i < 20000; i++ {
-		if Append(dir, fmt.Sprintf("s%d", i), Entry{SessionID: "s"}) == nil {
-			ok++
-		}
-	}
-	stop.Store(true)
-	<-done
-	ents, _ := os.ReadDir(outside)
-	assert.Empty(t, ents, "logs were created outside the brain")
-	assert.Positive(t, ok, "positive control: appends to the real dir succeed")
-}
-
-// The log file is swapped between a regular file and a symlink to another
-// file in the brain while Append runs: Append writes only after confirming
-// the path is the regular file it opened, so the other file never grows.
-func TestAppendNeverWritesThroughALogSwappedForASymlink(t *testing.T) {
-	brain := t.TempDir()
-	dir := filepath.Join(brain, "sessions")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	victim := filepath.Join(brain, "victim.md")
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	log := filepath.Join(dir, "s.jsonl")
-	var stop atomic.Bool
-	done := make(chan struct{})
-	go func() {
-		defer close(done)
-		tmp := log + ".swap"
-		for i := 0; !stop.Load(); i++ {
-			_ = os.Remove(tmp)
-			if i%2 == 0 {
-				_ = os.WriteFile(tmp, nil, 0o644)
-			} else {
-				_ = os.Symlink(filepath.Join("..", "victim.md"), tmp)
-			}
-			_ = os.Rename(tmp, log)
-		}
-	}()
-	ok := 0
-	for i := 0; i < 20000; i++ {
-		if Append(dir, "s", Entry{SessionID: "s"}) == nil {
-			ok++
-		}
-	}
-	stop.Store(true)
-	<-done
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched\n", string(got), "a log line was written through the swapped-in symlink")
-	assert.Positive(t, ok, "positive control: appends to the regular log succeed")
-}

ingestion/internal/session/session.go

@@ -49,12 +49,9 @@ type Attempt struct {
 // write (hyperguild#169).
 var idPattern = regexp.MustCompile(`^[A-Za-z0-9_][A-Za-z0-9._-]{0,127}$`)
 
-// ErrInvalidID is returned when a session id is not a plain file name.
-var ErrInvalidID = errors.New("session id is not a plain name")
-
 func checkID(sessionID string) error {
 	if !idPattern.MatchString(sessionID) {
-		return fmt.Errorf("%w: %q", ErrInvalidID, sessionID)
+		return fmt.Errorf("session id %q is not a plain name", sessionID)
 	}
 	return nil
 }
@@ -65,42 +62,14 @@ func Append(sessionsDir, sessionID string, entry Entry) error {
 	if err := checkID(sessionID); err != nil {
 		return err
 	}
-	// Opened through an os.Root on the sessions dir's parent (the brain dir),
+	if err := os.MkdirAll(sessionsDir, 0o755); err != nil {
-	// so a sessions dir swapped for a symlink after the check below can
-	// redirect the log only inside that parent, never outside it (#173; the
-	// in-brain swap is the #167 residual).
-	parentDir, name := filepath.Dir(sessionsDir), filepath.Base(sessionsDir)
-	if err := os.MkdirAll(parentDir, 0o755); err != nil {
-		return fmt.Errorf("create sessions parent: %w", err)
-	}
-	root, err := os.OpenRoot(parentDir)
-	if err != nil {
-		return fmt.Errorf("open sessions parent: %w", err)
-	}
-	defer func() { _ = root.Close() }()
-	if err := root.Mkdir(name, 0o755); err != nil && !errors.Is(err, fs.ErrExist) {
 		return fmt.Errorf("create sessions dir: %w", err)
 	}
-	// The sessions dir itself must be a real directory, not a symlink that
+	path := filepath.Join(sessionsDir, sessionID+".jsonl")
-	// redirects the log elsewhere (hyperguild#173).
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
-	if fi, err := root.Lstat(name); err != nil {
-		return fmt.Errorf("stat sessions dir: %w", err)
-	} else if !fi.IsDir() {
-		return fmt.Errorf("sessions dir %s is not a real directory", sessionsDir)
-	}
-	logRel := name + "/" + sessionID + ".jsonl"
-	f, err := root.OpenFile(logRel, os.O_CREATE|os.O_APPEND|os.O_WRONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
 	if err != nil {
 		return fmt.Errorf("open session log: %w", err)
 	}
-	// os.Root follows an in-root final symlink even with O_NOFOLLOW, so
-	// confirm, before writing, that the path is the regular file we opened.
-	hfi, herr := f.Stat()
-	lfi, lerr := root.Lstat(logRel)
-	if herr != nil || lerr != nil || !lfi.Mode().IsRegular() || !os.SameFile(lfi, hfi) {
-		_ = f.Close()
-		return fmt.Errorf("session log %s is not a regular file", logRel)
-	}
 
 	line, err := json.Marshal(entry)
 	if err != nil {

ingestion/internal/startupretry/startupretry.go

@@ -0,0 +1,75 @@
+// Package startupretry retries a startup dependency that may not be serving
+// yet, instead of exiting on its first failure.
+//
+// It exists for the cold-boot ordering race (#83): on a cluster restart the
+// ingestion pod can reach OIDC discovery before dex is answering, gets a 502
+// from ingress, and dies — after having already connected postgres, backfilled
+// the graph and ingested session batches, all of which the restart redoes.
+// Nothing is misconfigured in that scenario; the pod simply started first.
+//
+// The budget is bounded on purpose. Retrying forever would turn a genuine
+// misconfiguration (wrong issuer URL, bad audience) into a process that looks
+// healthy and never serves, which is harder to diagnose than a crash loop.
+package startupretry
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// Policy bounds the retry: at most Attempts calls, with the delay doubling
+// from Base and capped at Max.
+type Policy struct {
+	Attempts int           // total calls, including the first; < 1 means 1
+	Base     time.Duration // delay before the second attempt
+	Max      time.Duration // ceiling for the doubling delay
+}
+
+// Do calls fn until it succeeds, the attempt budget is spent, or ctx ends.
+//
+// The returned error wraps the last failure, so callers keep the diagnosis
+// they would have had without the retry.
+func Do[T any](ctx context.Context, p Policy, fn func(context.Context) (T, error)) (T, error) {
+	var zero T
+
+	attempts := p.Attempts
+	if attempts < 1 {
+		attempts = 1
+	}
+
+	delay := p.Base
+	var lastErr error
+
+	for i := range attempts {
+		if err := ctx.Err(); err != nil {
+			return zero, fmt.Errorf("startupretry: %w", err)
+		}
+
+		v, err := fn(ctx)
+		if err == nil {
+			return v, nil
+		}
+		lastErr = err
+
+		if i == attempts-1 {
+			break
+		}
+
+		if delay <= 0 {
+			delay = time.Second
+		}
+		if p.Max > 0 && delay > p.Max {
+			delay = p.Max
+		}
+
+		select {
+		case <-ctx.Done():
+			return zero, fmt.Errorf("startupretry: %w", ctx.Err())
+		case <-time.After(delay):
+		}
+		delay *= 2
+	}
+
+	return zero, fmt.Errorf("startupretry: gave up after %d attempts: %w", attempts, lastErr)
+}

ingestion/internal/startupretry/startupretry_test.go

@@ -0,0 +1,142 @@
+// ingestion/internal/startupretry/startupretry_test.go
+package startupretry
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+)
+
+func fastPolicy(attempts int) Policy {
+	return Policy{Attempts: attempts, Base: time.Millisecond, Max: 2 * time.Millisecond}
+}
+
+func TestDo_ReturnsImmediatelyOnFirstSuccess(t *testing.T) {
+	calls := 0
+	got, err := Do(context.Background(), fastPolicy(5), func(context.Context) (string, error) {
+		calls++
+		return "ready", nil
+	})
+	if err != nil {
+		t.Fatalf("Do: %v", err)
+	}
+	if got != "ready" {
+		t.Errorf("got %q, want %q", got, "ready")
+	}
+	if calls != 1 {
+		t.Errorf("calls = %d, want 1", calls)
+	}
+}
+
+func TestDo_SurvivesTransientFailuresThenSucceeds(t *testing.T) {
+	// The observed cold-boot race: dex is not serving yet, ingress answers
+	// 502 for the first few attempts, then discovery works.
+	calls := 0
+	got, err := Do(context.Background(), fastPolicy(5), func(context.Context) (string, error) {
+		calls++
+		if calls < 4 {
+			return "", errors.New("oidc discovery: status 502")
+		}
+		return "ready", nil
+	})
+	if err != nil {
+		t.Fatalf("Do returned %v — a transient 502 must not be fatal", err)
+	}
+	if got != "ready" {
+		t.Errorf("got %q, want %q", got, "ready")
+	}
+	if calls != 4 {
+		t.Errorf("calls = %d, want 4", calls)
+	}
+}
+
+func TestDo_GivesUpAfterTheAttemptBudgetAndReportsTheLastError(t *testing.T) {
+	// A genuinely broken issuer must still fail — retrying forever would turn
+	// a config error into a silent hang, which is worse than crash-looping.
+	last := errors.New("oidc discovery: status 404")
+	calls := 0
+
+	_, err := Do(context.Background(), fastPolicy(3), func(context.Context) (string, error) {
+		calls++
+		return "", last
+	})
+
+	if !errors.Is(err, last) {
+		t.Fatalf("err = %v, want it to wrap the last failure", err)
+	}
+	if calls != 3 {
+		t.Errorf("calls = %d, want 3 (the attempt budget)", calls)
+	}
+}
+
+func TestDo_StopsPromptlyWhenTheContextIsCancelled(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	calls := 0
+
+	done := make(chan struct{})
+	var err error
+	go func() {
+		defer close(done)
+		_, err = Do(ctx, Policy{Attempts: 100, Base: 50 * time.Millisecond, Max: time.Second},
+			func(context.Context) (string, error) {
+				calls++
+				if calls == 1 {
+					cancel()
+				}
+				return "", errors.New("still down")
+			})
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(2 * time.Second):
+		t.Fatal("Do did not return after context cancellation")
+	}
+	if !errors.Is(err, context.Canceled) {
+		t.Errorf("err = %v, want context.Canceled", err)
+	}
+}
+
+func TestDo_BacksOffAndIsCappedByMax(t *testing.T) {
+	var delays []time.Duration
+	p := Policy{Attempts: 5, Base: 10 * time.Millisecond, Max: 25 * time.Millisecond}
+
+	last := time.Now()
+	_, _ = Do(context.Background(), p, func(context.Context) (string, error) {
+		now := time.Now()
+		delays = append(delays, now.Sub(last))
+		last = now
+		return "", errors.New("down")
+	})
+
+	// delays[0] is the first call (no wait); the rest are the sleeps.
+	if len(delays) != 5 {
+		t.Fatalf("attempts = %d, want 5", len(delays))
+	}
+	if delays[1] >= delays[2] {
+		t.Errorf("backoff is not growing: %v then %v", delays[1], delays[2])
+	}
+	for i, d := range delays[1:] {
+		if d > 2*p.Max {
+			t.Errorf("delay %d = %v, exceeds the Max cap %v with slack", i+1, d, p.Max)
+		}
+	}
+}
+
+func TestPolicy_ZeroValueStillMakesOneAttempt(t *testing.T) {
+	// A caller that forgets to configure the policy must not silently get a
+	// no-op that returns a nil validator and a nil error.
+	calls := 0
+	_, err := Do(context.Background(), Policy{}, func(context.Context) (string, error) {
+		calls++
+		return "", errors.New("down")
+	})
+
+	if calls != 1 {
+		t.Errorf("calls = %d, want 1", calls)
+	}
+	if err == nil {
+		t.Error("err = nil, want the failure surfaced")
+	}
+}

ingestion/internal/symlinkguard/symlinkguard.go

@@ -18,14 +18,9 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"sync"
-	"sync/atomic"
 	"time"
 )
 
-// shutdownFlushTimeout bounds the final flush when Watch stops.
-var shutdownFlushTimeout = 5 * time.Second
-
 // DefaultInterval is used when Watch is given a non-positive interval.
 const DefaultInterval = 30 * time.Second
 
@@ -138,32 +133,13 @@ func Scan(brainDir string) (Result, error) {
 // queue until Notify succeeds (see alertQueue): an outage delays them, and
 // any that do not fit the bounded queue, or are undeliverable, are counted in
 // a summary that is never dropped, so every incident is delivered or counted.
-//
-// Delivery runs in its own goroutine (hyperguild#164): a hung notifier, with
-// a full queue, blocked one flush for several notify timeouts, and while the
-// scan waited on it a planted link stayed readable for several intervals.
-// The scan hands alerts over without blocking; any that do not fit are
-// counted in the summary. When ctx ends, Watch returns after a final flush
-// of what was handed over (bounded by shutdownFlushTimeout); alerts that
-// flush cannot deliver are counted in one error log line instead. That
-// shutdown path only runs for a caller that cancels ctx: cmd/server passes
-// context.Background(), so in production the flush on handoff is what keeps
-// alerts from waiting on a restart.
 func Watch(ctx context.Context, brainDir string, interval time.Duration, n Notifier) {
 	if interval <= 0 {
 		interval = DefaultInterval
 	}
 	t := time.NewTicker(interval)
 	defer t.Stop()
-	alerts := make(chan string, maxPending)
+	q := &alertQueue{}
-	var overflow atomic.Int64
-	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() { defer wg.Done(); deliver(ctx, interval, n, alerts, &overflow) }()
-	// The scan is the only sender: closing alerts tells deliver to drain and
-	// flush once more, and Watch returns only after it has.
-	defer func() { close(alerts); wg.Wait() }()
-	q := alertSender{alerts: alerts, overflow: &overflow}
 	reported := ""
 	for {
 		select {
@@ -192,76 +168,7 @@ func Watch(ctx context.Context, brainDir string, interval time.Duration, n Notif
 					". Readers may follow symlinks out of the brain; fix them.")
 			}
 		}
-	}
+		q.flush(ctx, n)
-}
-
-// alertSender hands alerts to deliver without ever blocking the scan; an
-// alert that does not fit is counted in overflow, which deliver adds to the
-// summary.
-type alertSender struct {
-	alerts   chan<- string
-	overflow *atomic.Int64
-}
-
-func (s alertSender) push(msg string) {
-	select {
-	case s.alerts <- msg:
-	default:
-		s.overflow.Add(1)
-	}
-}
-
-// deliver owns the alertQueue. It flushes as soon as an alert is handed
-// over, and again every interval while any are pending (outage retries).
-// When alerts is closed (Watch is stopping) it drains it and flushes once
-// more, bounded by shutdownFlushTimeout, so an alert handed over just before
-// shutdown is not lost (PR #180 review). Whatever that flush cannot deliver
-// is logged as one error with its counts, never dropped silently.
-func deliver(ctx context.Context, interval time.Duration, n Notifier, alerts <-chan string, overflow *atomic.Int64) {
-	t := time.NewTicker(interval)
-	defer t.Stop()
-	q := &alertQueue{}
-	// drain moves everything handed over into the queue; it reports false
-	// once alerts is closed.
-	drain := func() bool {
-		defer func() { q.suppressed += int(overflow.Swap(0)) }()
-		for {
-			select {
-			case msg, ok := <-alerts:
-				if !ok {
-					return false
-				}
-				q.push(msg)
-			default:
-				return true
-			}
-		}
-	}
-	for {
-		select {
-		case msg, ok := <-alerts:
-			if ok {
-				q.push(msg)
-				ok = drain()
-			}
-			if !ok {
-				q.suppressed += int(overflow.Swap(0))
-				fctx, cancel := context.WithTimeout(context.WithoutCancel(ctx), shutdownFlushTimeout)
-				q.flush(fctx, n)
-				cancel()
-				if len(q.items) > 0 || q.suppressed > 0 {
-					slog.Error("symlink tripwire alerts not delivered at shutdown",
-						"undelivered", len(q.items), "suppressed", q.suppressed)
-				}
-				return
-			}
-			q.flush(ctx, n)
-		case <-t.C:
-			if !drain() {
-				continue // the closed channel is handled by the case above
-			}
-			q.flush(ctx, n)
-		}
 	}
 }
 

ingestion/internal/symlinkguard/symlinkguard_test.go

@@ -1,12 +1,10 @@
 package symlinkguard
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"os"
-	"log/slog"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -347,19 +345,13 @@ func TestWatchDropsAMessageThatNeverSendsSoLaterAlertsFlow(t *testing.T) {
 	}, 3*time.Second, 10*time.Millisecond, "a later alert is delivered despite a poison message")
 }
 
-// toggleNotifier fails while down is set. Like the real audit.NtfyNotifier
+// toggleNotifier fails while down is set.
-// (http.NewRequestWithContext), it also fails, without recording, when its
-// ctx is already done (PR #180 round 2: notifiers that ignored ctx let a
-// final flush on the cancelled ctx pass).
 type toggleNotifier struct {
 	recNotifier
 	down atomic.Bool
 }
 
 func (r *toggleNotifier) Notify(ctx context.Context, m string) error {
-	if err := ctx.Err(); err != nil {
-		return err
-	}
 	if r.down.Load() {
 		return errors.New("ntfy down")
 	}
@@ -504,271 +496,3 @@ func TestWatchDropsAPoisonMessageAndCountsIt(t *testing.T) {
 		return false
 	}, 3*time.Second, 5*time.Millisecond, "the dropped poison alert is counted in a summary")
 }
-
-// hungNotifier answers every Notify only after latency (or when ctx ends),
-// with an outage error: an ntfy that accepts connections but never responds
-// until its timeout.
-type hungNotifier struct{ latency time.Duration }
-
-func (h hungNotifier) Notify(ctx context.Context, _ string) error {
-	select {
-	case <-time.After(h.latency):
-	case <-ctx.Done():
-	}
-	return errors.New("ntfy timeout")
-}
-
-func waitGone(t *testing.T, link string) {
-	t.Helper()
-	require.Eventually(t, func() bool { _, err := os.Lstat(link); return os.IsNotExist(err) }, 10*time.Second, time.Millisecond)
-}
-
-// hyperguild#164: alerts were flushed in the scan goroutine, so with a hung
-// ntfy and a full queue one flush (6 x notify timeout) delayed the next scan.
-// The notifier here is slower than the interval, as in production (10 s
-// timeout vs 30 s interval with 6 messages), so the alert handoff is full:
-// a scan that waited on it would keep a link for seconds.
-func TestWatchLinkLifetimeStaysNearOneIntervalWithANotifierSlowerThanTheInterval(t *testing.T) {
-	const interval = 100 * time.Millisecond
-	brain := t.TempDir()
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	go Watch(ctx, brain, interval, hungNotifier{latency: 400 * time.Millisecond})
-
-	for i := 0; i < 2*maxPending+3; i++ { // overfill queue and handoff
-		link := filepath.Join(brain, "fill"+strconv.Itoa(i))
-		require.NoError(t, os.Symlink(t.TempDir(), link))
-		waitGone(t, link)
-	}
-	var worst time.Duration
-	for i := 0; i < 6; i++ {
-		link := filepath.Join(brain, "probe"+strconv.Itoa(i))
-		require.NoError(t, os.Symlink(t.TempDir(), link))
-		planted := time.Now()
-		waitGone(t, link)
-		worst = max(worst, time.Since(planted))
-	}
-	assert.LessOrEqual(t, worst, interval+interval/2, "worst link lifetime %v with a hung notifier", worst)
-}
-
-// Review of PR #180: delivery waited for its own tick, about one interval
-// after the removal. An alert is now flushed as soon as it is handed over.
-func TestWatchDeliversARemovalAlertWellWithinOneInterval(t *testing.T) {
-	const interval = 400 * time.Millisecond
-	brain := t.TempDir()
-	n := &recNotifier{}
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	go Watch(ctx, brain, interval, n)
-	link := filepath.Join(brain, "prompt")
-	require.NoError(t, os.Symlink(t.TempDir(), link))
-	waitGone(t, link)
-	removed := time.Now()
-	require.Eventually(t, func() bool { return n.count() == 1 }, 2*time.Second, time.Millisecond)
-	assert.Less(t, time.Since(removed), interval/4)
-}
-
-// Review of PR #180: on ctx end, deliver returned without draining what the
-// scan had handed over, so a removal just before shutdown was neither
-// delivered nor counted. Watch now drains and flushes before returning.
-func TestWatchDeliversAnAlertHandedOverJustBeforeShutdown(t *testing.T) {
-	for i := 0; i < 20; i++ {
-		brain := t.TempDir()
-		n := &recNotifier{}
-		ctx, cancel := context.WithCancel(context.Background())
-		done := make(chan struct{})
-		go func() { Watch(ctx, brain, 5*time.Millisecond, n); close(done) }()
-		link := filepath.Join(brain, "late")
-		require.NoError(t, os.Symlink(t.TempDir(), link))
-		waitGone(t, link)
-		cancel()
-		<-done
-		require.Equal(t, 1, n.count(), "iteration %d: the removal alert was lost at shutdown", i)
-	}
-}
-
-// blockingNotifier holds every Notify until its ctx ends, tracking calls in
-// flight.
-type blockingNotifier struct{ inFlight atomic.Int32 }
-
-func (b *blockingNotifier) Notify(ctx context.Context, _ string) error {
-	b.inFlight.Add(1)
-	defer b.inFlight.Add(-1)
-	<-ctx.Done()
-	return ctx.Err()
-}
-
-// Watch does not return while its delivery goroutine is still notifying.
-func TestWatchReturnsOnlyAfterDeliveryHasStopped(t *testing.T) {
-	prev := shutdownFlushTimeout
-	shutdownFlushTimeout = 50 * time.Millisecond
-	t.Cleanup(func() { shutdownFlushTimeout = prev })
-	brain := t.TempDir()
-	n := &blockingNotifier{}
-	ctx, cancel := context.WithCancel(context.Background())
-	done := make(chan struct{})
-	go func() { Watch(ctx, brain, 5*time.Millisecond, n); close(done) }()
-	link := filepath.Join(brain, "x")
-	require.NoError(t, os.Symlink(t.TempDir(), link))
-	waitGone(t, link)
-	require.Eventually(t, func() bool { return n.inFlight.Load() == 1 }, 2*time.Second, time.Millisecond)
-	cancel()
-	select {
-	case <-done:
-	case <-time.After(5 * time.Second):
-		t.Fatal("Watch did not return after cancel")
-	}
-	assert.Zero(t, n.inFlight.Load(), "Notify still running after Watch returned")
-}
-
-// slowToggleNotifier fails slowly (a hung ntfy) while down, then records.
-type slowToggleNotifier struct {
-	recNotifier
-	down    atomic.Bool
-	latency time.Duration
-}
-
-func (r *slowToggleNotifier) Notify(ctx context.Context, m string) error {
-	if r.down.Load() {
-		select {
-		case <-time.After(r.latency):
-		case <-ctx.Done():
-		}
-		return errors.New("ntfy timeout")
-	}
-	return r.recNotifier.Notify(ctx, m)
-}
-
-// Review of PR #180: with a slow notifier the scan's handoff overflows, and
-// those alerts exist only in the overflow counter. Every removal is still
-// delivered or counted in the summary.
-func TestWatchCountsHandoffOverflowWithASlowNotifier(t *testing.T) {
-	brain := t.TempDir()
-	n := &slowToggleNotifier{latency: 30 * time.Millisecond}
-	n.down.Store(true)
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	go Watch(ctx, brain, 2*time.Millisecond, n)
-	const plants = 40
-	for i := 0; i < plants; i++ {
-		link := filepath.Join(brain, "ov"+strconv.Itoa(i))
-		require.NoError(t, os.Symlink(t.TempDir(), link))
-		waitGone(t, link)
-	}
-	n.down.Store(false)
-	delivered, counted := 0, 0
-	require.Eventually(t, func() bool {
-		n.mu.Lock()
-		defer n.mu.Unlock()
-		delivered, counted = 0, 0
-		for _, m := range n.msgs {
-			if strings.Contains(m, "removed 1 symlink(s)") {
-				delivered++
-			}
-			if i := strings.Index(m, "): "); i >= 0 && strings.Contains(m, "suppressed") {
-				var c int
-				_, _ = fmt.Sscanf(m[i+3:], "%d", &c)
-				counted += c
-			}
-		}
-		return delivered+counted == plants
-	}, 5*time.Second, 10*time.Millisecond, "delivered %d + counted %d of %d", delivered, counted, plants)
-}
-
-// An alert still queued when Watch stops (its send failed, the notifier has
-// since recovered, the retry tick has not come) is flushed once more before
-// Watch returns, on a ctx that is not the cancelled one: toggleNotifier fails
-// on a done ctx, as the real ntfy notifier does.
-func TestWatchFinalFlushSendsAQueuedAlertOnACtxThatOutlivesTheCancel(t *testing.T) {
-	brain := t.TempDir()
-	n := &toggleNotifier{}
-	n.down.Store(true)
-	ctx, cancel := context.WithCancel(context.Background())
-	done := make(chan struct{})
-	go func() { Watch(ctx, brain, 300*time.Millisecond, n); close(done) }()
-	link := filepath.Join(brain, "queued")
-	require.NoError(t, os.Symlink(t.TempDir(), link))
-	waitGone(t, link)
-	time.Sleep(20 * time.Millisecond) // let the immediate send fail
-	n.down.Store(false)
-	cancel()
-	<-done
-	assert.Equal(t, 1, n.count(), "the queued alert was not flushed at shutdown")
-}
-
-// lockedBuffer is a goroutine-safe log sink: Watch goroutines of earlier
-// tests may still log while one test captures.
-type lockedBuffer struct {
-	mu  sync.Mutex
-	buf bytes.Buffer
-}
-
-func (b *lockedBuffer) Write(p []byte) (int, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	return b.buf.Write(p)
-}
-
-func (b *lockedBuffer) String() string { b.mu.Lock(); defer b.mu.Unlock(); return b.buf.String() }
-
-func captureLog(t *testing.T) *lockedBuffer {
-	t.Helper()
-	b := &lockedBuffer{}
-	prev := slog.Default()
-	slog.SetDefault(slog.New(slog.NewTextHandler(b, nil)))
-	t.Cleanup(func() { slog.SetDefault(prev) })
-	return b
-}
-
-// PR #180 round 2: when the final flush fails (ntfy hung at shutdown) the
-// undelivered alerts vanished with only "will retry" warnings. Watch now logs
-// one error with both counts.
-func TestWatchLogsUndeliveredAndSuppressedCountsWhenTheFinalFlushFails(t *testing.T) {
-	prev := shutdownFlushTimeout
-	shutdownFlushTimeout = 50 * time.Millisecond
-	t.Cleanup(func() { shutdownFlushTimeout = prev })
-	logs := captureLog(t)
-	brain := t.TempDir()
-	ctx, cancel := context.WithCancel(context.Background())
-	done := make(chan struct{})
-	go func() { Watch(ctx, brain, 5*time.Millisecond, hungNotifier{latency: time.Hour}); close(done) }()
-	link := filepath.Join(brain, "lost")
-	require.NoError(t, os.Symlink(t.TempDir(), link))
-	waitGone(t, link)
-	cancel()
-	<-done
-	out := logs.String()
-	assert.Contains(t, out, "level=ERROR")
-	assert.Contains(t, out, `msg="symlink tripwire alerts not delivered at shutdown"`)
-	assert.Contains(t, out, "undelivered=1")
-	assert.Contains(t, out, "suppressed=0")
-}
-
-// deliver, given a handoff that already holds alerts and is closed, moves them
-// into the queue and runs the final flush, even though the ctx is cancelled:
-// the drain-on-close path, without depending on when the close lands.
-func TestDeliverFlushesAlertsDrainedFromAClosedHandoffOnACancelledCtx(t *testing.T) {
-	alerts := make(chan string, 3)
-	alerts <- "a1"
-	alerts <- "a2"
-	close(alerts)
-	ctx, cancel := context.WithCancel(context.Background())
-	cancel()
-	n := &toggleNotifier{}
-	var overflow atomic.Int64
-	deliver(ctx, time.Hour, n, alerts, &overflow)
-	assert.Equal(t, []string{"a1", "a2"}, n.msgs)
-}
-
-// PR #180 round 2: when the first receive after close finds the handoff empty,
-// overflow counted by the scan was never moved into the summary.
-func TestDeliverCountsOverflowWhenTheHandoffIsClosedAndEmpty(t *testing.T) {
-	alerts := make(chan string)
-	close(alerts)
-	n := &recNotifier{}
-	var overflow atomic.Int64
-	overflow.Store(3)
-	deliver(context.Background(), time.Hour, n, alerts, &overflow)
-	require.Len(t, n.msgs, 1)
-	assert.Contains(t, n.msgs[0], "3 further alert(s)")
-}

ingestion/internal/vectorstore/sync_root_test.go

@@ -42,11 +42,6 @@ func TestSyncRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
 	brain := t.TempDir()
 	writeNote(t, brain, "wiki/w/facts/ok.md", "inside note")
 	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(brain, "wiki", "w", "facts", "leak.md")))
-	// A link to a file elsewhere in the brain: os.Root allows it, only the
-	// regular-file checks refuse it (hyperguild#171). raw/ is not a scan root,
-	// so its sentinel can only arrive through the link.
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(brain, "wiki", "w", "facts", "inlink.md")))
 
 	emb := &recordingEmbedder{}
 	store := &stubStore{}
@@ -56,7 +51,6 @@ func TestSyncRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
 	assert.NotContains(t, emb.all(), brainfstest.Sentinel)
 	for p := range store.upserts {
 		assert.NotContains(t, p, "leak.md")
-		assert.NotContains(t, p, "inlink.md")
 	}
 
 	p := filepath.Join(brain, "knowledge", "r.md")
@@ -67,7 +61,6 @@ func TestSyncRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
 		return e.all()
 	}
 	brainfstest.AssertNoLeak(t, p, "inside", 1500*time.Millisecond, sync)
-	brainfstest.AssertNoLeakFrom(t, p, "inside", inBrain, 1500*time.Millisecond, sync)
 	brainfstest.AssertNoHang(t, p, "inside", 1500*time.Millisecond, 6*time.Second, func() { _ = sync() })
 }
 

ingestion/internal/wiki/index.go

@@ -3,9 +3,10 @@ package wiki
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"github.com/mathiasbq/hyperguild/ingestion/internal/textutil"
 )
 
@@ -15,11 +16,6 @@ func RebuildIndex(brainDir, date string) error {
 	if err != nil {
 		return fmt.Errorf("load inventory: %w", err)
 	}
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
 
 	total := len(inv[PageTypeConcept]) + len(inv[PageTypeEntity]) + len(inv[PageTypeSource])
 	var sb strings.Builder
@@ -38,7 +34,7 @@ func RebuildIndex(brainDir, date string) error {
 		label := strings.ToUpper(string(pt)[:1]) + string(pt)[1:]
 		fmt.Fprintf(&sb, "## %s\n\n", label)
 		for _, e := range entries {
-			summary := pageFirstSentence(bfs, e)
+			summary := pageFirstSentence(brainDir, e)
 			if summary != "" {
 				fmt.Fprintf(&sb, "- [[%s|%s]] — %s\n", e.Slug, e.Title, summary)
 			} else {
@@ -48,14 +44,13 @@ func RebuildIndex(brainDir, date string) error {
 		sb.WriteString("\n")
 	}
 
-	// Written through the brain root, never through a symlink (#158).
+	dest := filepath.Join(brainDir, "wiki", "index.md")
-	return bfs.PutRegular("wiki/index.md", []byte(sb.String()))
+	return os.WriteFile(dest, []byte(sb.String()), 0o644)
 }
 
-// pageFirstSentence reads the page through the brain root, regular files
+func pageFirstSentence(brainDir string, e Entry) string {
-// only (hyperguild#157).
+	path := filepath.Join(brainDir, "wiki", string(e.Type), e.Slug+".md")
-func pageFirstSentence(bfs *brainfs.Brain, e Entry) string {
+	content, err := os.ReadFile(path)
-	content, err := bfs.ReadRegular("wiki/" + string(e.Type) + "/" + e.Slug + ".md")
 	if err != nil {
 		return ""
 	}

ingestion/internal/wiki/inventory.go

@@ -3,45 +3,36 @@ package wiki
 
 import (
 	"bufio"
-	"bytes"
-	"errors"
 	"fmt"
-	"io/fs"
+	"os"
+	"path/filepath"
 	"strings"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 )
 
 // LoadInventory walks brain/wiki/ and returns all pages grouped by type.
-// Missing subdirectories are silently skipped. Pages are listed and read
+// Missing subdirectories are silently skipped.
-// through the brain root, regular files only (hyperguild#157); a type
-// directory that is a symlink is an error.
 func LoadInventory(brainDir string) (map[PageType][]Entry, error) {
 	result := map[PageType][]Entry{
 		PageTypeConcept: {},
 		PageTypeEntity:  {},
 		PageTypeSource:  {},
 	}
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return nil, fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
 	for pt := range result {
-		dir := "wiki/" + string(pt)
+		dir := filepath.Join(brainDir, "wiki", string(pt))
-		names, err := bfs.ReadDirRegular(dir)
+		entries, err := os.ReadDir(dir)
-		if errors.Is(err, fs.ErrNotExist) {
+		if os.IsNotExist(err) {
 			continue
 		}
 		if err != nil {
 			return nil, fmt.Errorf("read dir %s: %w", dir, err)
 		}
-		for _, name := range names {
+		for _, e := range entries {
-			if !strings.HasSuffix(name, ".md") {
+			if e.IsDir() || !strings.HasSuffix(e.Name(), ".md") {
 				continue
 			}
-			slug := strings.TrimSuffix(name, ".md")
+			slug := strings.TrimSuffix(e.Name(), ".md")
-			title, aliases := readFrontmatter(bfs, dir+"/"+name, slug)
+			path := filepath.Join(dir, e.Name())
+			title, aliases := readFrontmatter(path, slug)
 			result[pt] = append(result[pt], Entry{Slug: slug, Title: title, Aliases: aliases, Type: pt})
 		}
 	}
@@ -50,14 +41,15 @@ func LoadInventory(brainDir string) (map[PageType][]Entry, error) {
 
 // readFrontmatter extracts title and aliases from YAML frontmatter.
 // Falls back to slug for title and empty aliases on any error.
-func readFrontmatter(bfs *brainfs.Brain, rel, fallbackSlug string) (title string, aliases []string) {
+func readFrontmatter(path, fallbackSlug string) (title string, aliases []string) {
 	title = fallbackSlug
-	content, err := bfs.ReadRegular(rel)
+	f, err := os.Open(path)
 	if err != nil {
 		return
 	}
+	defer f.Close() //nolint:errcheck
 
-	scanner := bufio.NewScanner(bytes.NewReader(content))
+	scanner := bufio.NewScanner(f)
 	inFM := false
 	inAliases := false
 	for scanner.Scan() {

ingestion/internal/wiki/log.go

@@ -3,7 +3,8 @@ package wiki
 
 import (
 	"fmt"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
+	"os"
+	"path/filepath"
 	"strings"
 )
 
@@ -26,14 +27,14 @@ func AppendLog(brainDir, source string, pages, warnings []string, date string) e
 	}
 	sb.WriteString("\n")
 
-	// Appended through the brain root, never through a symlink (#158).
+	logPath := filepath.Join(brainDir, "log.md")
-	bfs, err := brainfs.Open(brainDir)
+	f, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
 	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
+		return fmt.Errorf("open log: %w", err)
 	}
-	defer func() { _ = bfs.Close() }()
+	if _, err = f.WriteString(sb.String()); err != nil {
-	if err := bfs.AppendRegular("log.md", []byte(sb.String())); err != nil {
+		f.Close() //nolint:errcheck
 		return fmt.Errorf("write log: %w", err)
 	}
-	return nil
+	return f.Close()
 }

ingestion/internal/wiki/root_test.go

@@ -1,79 +0,0 @@
-package wiki
-
-import (
-	"fmt"
-	"os"
-	"path/filepath"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
-)
-
-// hyperguild#157 slice 4: LoadInventory listed wiki/<type>/ with os.ReadDir
-// and opened each .md by path, so a symlinked page put the target's title and
-// aliases into the inventory (and the LLM prompts built from it), and a FIFO
-// hung it. RebuildIndex read first sentences the same way.
-func TestLoadInventoryRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
-	brain := t.TempDir()
-	dir := filepath.Join(brain, "wiki", "concepts")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "ok.md"), []byte("---\ntitle: zqinside\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(dir, "leak.md")))
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "s.md"), filepath.Join(dir, "inlink.md")))
-
-	inv, err := LoadInventory(brain)
-	require.NoError(t, err)
-	got := fmt.Sprintf("%+v", inv)
-	assert.Contains(t, got, "zqinside", "positive control")
-	assert.NotContains(t, got, brainfstest.Sentinel)
-	assert.NotContains(t, got, "leak", "a symlinked page is not listed")
-	assert.NotContains(t, got, "inlink", "a page linked to another brain file is not listed")
-
-	p := filepath.Join(dir, "r.md")
-	read := func() string {
-		inv, _ := LoadInventory(brain)
-		return fmt.Sprintf("%+v", inv)
-	}
-	brainfstest.AssertNoLeak(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, read)
-	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: zqinside\n---\n", inBrain, 1500*time.Millisecond, read)
-	brainfstest.AssertNoHang(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
-}
-
-func TestLoadInventoryReturnsErrNotRegularForASymlinkedTypeDir(t *testing.T) {
-	brain := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "wiki"), 0o755))
-	require.NoError(t, os.MkdirAll(filepath.Join(brain, "raw"), 0o755))
-	require.NoError(t, os.WriteFile(filepath.Join(brain, "raw", "r.md"), []byte("---\ntitle: zqrawonly\n---\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(brain, "wiki", "concepts")))
-	inv, err := LoadInventory(brain)
-	require.ErrorIs(t, err, brainfs.ErrNotRegular)
-	assert.NotContains(t, fmt.Sprintf("%+v", inv), "zqrawonly")
-}
-
-func TestRebuildIndexDoesNotReadAPageSwappedForASymlink(t *testing.T) {
-	brain := t.TempDir()
-	dir := filepath.Join(brain, "wiki", "concepts")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	p := filepath.Join(dir, "r.md")
-	require.NoError(t, os.WriteFile(p, []byte("---\ntitle: R\n---\nzqinside sentence.\n"), 0o644))
-	require.NoError(t, RebuildIndex(brain, "2026-10-04"))
-	idx, err := os.ReadFile(filepath.Join(brain, "wiki", "index.md"))
-	require.NoError(t, err)
-	require.Contains(t, string(idx), "zqinside", "positive control: the summary is read")
-
-	read := func() string {
-		_ = RebuildIndex(brain, "2026-10-04")
-		b, _ := os.ReadFile(filepath.Join(brain, "wiki", "index.md"))
-		return string(b)
-	}
-	brainfstest.AssertNoLeak(t, p, "---\ntitle: R\n---\nzqinside sentence.\n", 1500*time.Millisecond, read)
-	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))
-	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: R\n---\nzqinside sentence.\n", inBrain, 1500*time.Millisecond, read)
-	brainfstest.AssertNoHang(t, p, "---\ntitle: R\n---\nzqinside sentence.\n", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
-}

ingestion/internal/wiki/writers_redirect_test.go

@@ -1,35 +0,0 @@
-package wiki
-
-import (
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// hyperguild#158: RebuildIndex wrote wiki/index.md and AppendLog appended
-// log.md with os.WriteFile / os.OpenFile, so a symlinked file was written
-// through.
-func TestRebuildIndexAndAppendLogDoNotWriteThroughSymlinks(t *testing.T) {
-	b := t.TempDir()
-	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "concepts"), 0o755))
-	victim := filepath.Join(b, "raw", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "raw", "v.md"), filepath.Join(b, "wiki", "index.md")))
-	require.NoError(t, os.Symlink(filepath.Join("raw", "v.md"), filepath.Join(b, "log.md")))
-
-	assert.Error(t, RebuildIndex(b, "2026-10-05"))
-	assert.Error(t, AppendLog(b, "src", []string{"p"}, nil, "2026-10-05"))
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched", string(got))
-
-	require.NoError(t, os.Remove(filepath.Join(b, "wiki", "index.md")))
-	require.NoError(t, os.Remove(filepath.Join(b, "log.md")))
-	require.NoError(t, RebuildIndex(b, "2026-10-05"), "positive control")
-	require.NoError(t, AppendLog(b, "src", []string{"p"}, nil, "2026-10-05"), "positive control")
-	l, _ := os.ReadFile(filepath.Join(b, "log.md"))
-	assert.Contains(t, string(l), "src")
-}