test(pipeline): pin BackfillRefs' page read with a swap race (#157)

Review round 1 on PR #176: reverting the BackfillRefs concept-page read
to os.ReadFile left every test green. The static symlinked page never
reaches that read, because LoadInventory does not list it; the read is
reachable only when a page listed as regular is swapped for a symlink
before it is read. New test does that against an in-brain target and
reads the page back with O_NOFOLLOW; red under the flip (2/2), green
3/3 on head.

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

ingestion/cmd/server/jwt_validator.go

@@ -2,25 +2,24 @@ package main
 
 import (
 	"context"
-	"fmt"
 	"log/slog"
 
 	chassisauth "git.d-ma.be/mathias/mcp-chassis/auth"
+
+	"github.com/mathiasbq/hyperguild/ingestion/internal/startupretry"
 )
 
-// buildJWTValidator builds the JWT validator for issuer (nil when issuer is
+// buildJWTValidator runs OIDC discovery under policy, so a 502 from an auth
-// empty: JWT auth disabled). Since mcp-chassis v0.7 construction no longer
+// upstream that is not serving yet on a cold boot is retried instead of
-// fails when OIDC discovery does (mcp-chassis#4): the issuer resolves lazily,
+// exiting (#83). It honours ctx between attempts.
-// and until it does a JWT is answered 503-and-retry, not 401. That replaces
+func buildJWTValidator(
-// #83's boot-time retry loop (hyperguild#155). An issuer still unresolved at
+	ctx context.Context, logger *slog.Logger, issuer, audience string, policy startupretry.Policy,
-// boot is logged, so a misconfigured issuer is visible rather than silent.
+) (*chassisauth.JWTValidator, error) {
-func buildJWTValidator(ctx context.Context, logger *slog.Logger, issuer, audience string) (*chassisauth.JWTValidator, error) {
+	return startupretry.Do(ctx, policy, func(ctx context.Context) (*chassisauth.JWTValidator, error) {
-	v, err := chassisauth.NewJWTValidator(ctx, issuer, audience)
+		v, err := chassisauth.NewJWTValidator(ctx, issuer, audience)
-	if err != nil {
+		if err != nil {
-		return nil, fmt.Errorf("build jwt validator: %w", err)
+			logger.Warn("oidc discovery not ready, retrying", "err", err)
-	}
+		}
-	if ok, rerr := v.Ready(ctx); !ok {
+		return v, err
-		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

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"bytes"
 	"context"
 	"io"
 	"log/slog"
@@ -9,11 +8,12 @@ import (
 	"net/http/httptest"
 	"sync/atomic"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/mathiasbq/hyperguild/ingestion/internal/metrics"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/startupretry"
 )
 
 // fakeIssuer answers OIDC discovery with 502 for the first fail requests, as
@@ -41,71 +41,46 @@ func fakeIssuer(t *testing.T, fail int32) (*httptest.Server, *atomic.Int32) {
 	return srv, &discoveries
 }
 
-// #83 retried discovery at boot because chassis v0.2.0 failed construction on
+var fastPolicy = startupretry.Policy{Attempts: 8, Base: time.Millisecond, Max: 5 * time.Millisecond}
-// 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
+func TestBuildJWTValidatorRetriesDiscovery502sThenSucceeds(t *testing.T) {
-// (hyperguild#155). An unresolved issuer is logged at boot.
+	srv, discoveries := fakeIssuer(t, 3)
-func TestBuildJWTValidatorReturnsAValidatorWhileDiscovery502s(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
-	srv, _ := fakeIssuer(t, 1000)
+	defer cancel()
-	var buf bytes.Buffer
+
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.NewTextHandler(&buf, nil)), srv.URL, "brain")
+	v, err := buildJWTValidator(ctx, slog.New(slog.DiscardHandler), srv.URL, "brain", fastPolicy)
 	require.NoError(t, err)
 	assert.NotNil(t, v)
-	assert.Contains(t, buf.String(), "jwt issuer not resolved at boot")
+	assert.Equal(t, int32(4), discoveries.Load(), "three 502s, then the successful discovery")
 }
 
-func TestBuildJWTValidatorLogsNothingAgainstAHealthyIssuer(t *testing.T) {
+func TestBuildJWTValidatorGivesUpAfterTheBudgetWithTheLastError(t *testing.T) {
-	srv, _ := fakeIssuer(t, 0)
+	srv, discoveries := fakeIssuer(t, 1000)
-	var buf bytes.Buffer
+	ctx, cancel := context.WithCancel(context.Background())
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.NewTextHandler(&buf, nil)), srv.URL, "brain")
+	defer cancel()
-	require.NoError(t, err)
+
-	assert.NotNil(t, v)
+	_, err := buildJWTValidator(ctx, slog.New(slog.DiscardHandler), srv.URL, "brain", fastPolicy)
-	assert.NotContains(t, buf.String(), "not resolved")
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "status 502")
+	assert.Equal(t, int32(8), discoveries.Load(), "bounded: exactly the attempt budget")
 }
 
-func TestBuildJWTValidatorIsNilWithoutAnIssuer(t *testing.T) {
+func TestBuildJWTValidatorStopsRetryingWhenTheContextIsCancelled(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")
+	ctx, cancel := context.WithCancel(context.Background())
-	require.NoError(t, err)
+	slow := startupretry.Policy{Attempts: 8, Base: time.Hour, Max: time.Hour}
-	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
+	done := make(chan error, 1)
-// asserted on it. With the issuer unresolved, a JWT on /mcp answers 503 too,
+	go func() {
-// so /mcp's middleware was built with the JWT validator.
+		_, err := buildJWTValidator(ctx, slog.New(slog.DiscardHandler), srv.URL, "brain", slow)
-func TestBuildMuxAnswers503ToAJWTOnMCPWhileTheIssuerIsUnresolved(t *testing.T) {
+		done <- err
-	srv, _ := fakeIssuer(t, 1000)
+	}()
-	v, err := buildJWTValidator(context.Background(), slog.New(slog.DiscardHandler), srv.URL, "brain")
+	time.Sleep(50 * time.Millisecond)
-	require.NoError(t, err)
+	cancel()
-	mux, err := buildMux(restAuth{token: routesTok, validator: v, realm: "brain"}, testHandler(t),
+	select {
-		okHandler("mcp"), metrics.New(), nil)
+	case err := <-done:
-	require.NoError(t, err)
+		assert.ErrorIs(t, err, context.Canceled)
-	code, _ := do(t, mux, "POST", "/mcp", "Bearer aaa.bbb.ccc")
+	case <-time.After(3 * time.Second):
-	assert.Equal(t, http.StatusServiceUnavailable, code)
+		t.Fatal("did not return after the context was cancelled")
-}
+	}
-
-// 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 +369,21 @@ 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.
+	//   - Constructing it first means a genuine config error (wrong issuer,
+	//     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 := buildJWTValidator(ctx, logger,
-		os.Getenv("DEX_ISSUER_URL"), os.Getenv("MCP_AUDIENCE"))
+		os.Getenv("DEX_ISSUER_URL"), os.Getenv("MCP_AUDIENCE"),
+		startupretry.Policy{Attempts: 8, Base: time.Second, Max: 30 * time.Second})
 	if err != nil {
 		logger.Error("build jwt validator", "err", err)
 		os.Exit(1)
@@ -516,6 +523,8 @@ 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 +548,7 @@ 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 +590,19 @@ 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 +623,7 @@ 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

@@ -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

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=

ingestion/internal/api/update.go

@@ -3,18 +3,15 @@ package api
 import (
 	"crypto/sha256"
 	"encoding/hex"
-	"errors"
 	"fmt"
-	"io/fs"
+	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 	"os"
 	"path/filepath"
 	"strings"
 	"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/notes"
 )
 
 // ContentHash returns the lowercase hex sha256 of b. It is the note's
@@ -94,23 +91,14 @@ func UpdateNote(brainDir string, opts UpdateNoteOptions) (relPath, contentHash,
 		rel = filepath.ToSlash(rel)
 	}
 
-	// The path is caller-supplied (brain_update): resolve it as brain_edit
+	rel, abs, err := resolveWithin(brainDir, rel)
-	// does, knowledge/ and wiki/ notes only, and read and rewrite it through
-	// the brain root, never through a symlink (hyperguild#169).
-	t, err := notes.Resolve(brainDir, rel, notes.ScopeNotes)
 	if err != nil {
 		return "", "", "", err
 	}
-	rel = t.Rel
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return "", "", "", fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
 
-	prior, err := bfs.ReadRegular(rel)
+	prior, err := os.ReadFile(abs)
 	if err != nil {
-		if errors.Is(err, fs.ErrNotExist) {
+		if os.IsNotExist(err) {
 			return "", "", "", fmt.Errorf("note %q does not exist: use brain_write to create", rel)
 		}
 		return "", "", "", fmt.Errorf("read target: %w", err)
@@ -176,7 +164,7 @@ func UpdateNote(brainDir string, opts UpdateNoteOptions) (relPath, contentHash,
 		return "", "", "", err
 	}
 	out := []byte(stamped)
-	if err := bfs.WriteRegular(rel, out); err != nil {
+	if err := os.WriteFile(abs, out, 0o644); err != nil {
 		return "", "", "", fmt.Errorf("write: %w", err)
 	}
 	return rel, ContentHash(out), priorHash, nil

ingestion/internal/api/update_scope_test.go

@@ -1,112 +0,0 @@
-package api_test
-
-import (
-	"os"
-	"path/filepath"
-	"sync"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/api"
-)
-
-// brain_update passed the caller's path through resolveWithin, a lexical
-// containment check only: any file in the brain could be superseded
-// (classification.yaml, raw/, sessions/), and a final symlink was written
-// through. It now resolves like brain_edit: knowledge/ and wiki/ notes only,
-// read and rewritten through the brain root.
-func TestUpdateNoteRefusesPathsOutsideKnowledgeAndWikiNotes(t *testing.T) {
-	brain := t.TempDir()
-	files := map[string]string{
-		"classification.yaml": "levels: {}\n",
-		"raw/r.md":            "raw\n",
-		"sessions/s.jsonl":    "{}\n",
-		"wiki/w/facts/ok.md":  "---\ntitle: ok\n---\nold\n",
-		"knowledge/k.md":      "---\ntitle: k\n---\nold\n",
-		"wiki/w/facts/x.txt":  "txt\n",
-	}
-	for rel, body := range files {
-		p := filepath.Join(brain, filepath.FromSlash(rel))
-		require.NoError(t, os.MkdirAll(filepath.Dir(p), 0o755))
-		require.NoError(t, os.WriteFile(p, []byte(body), 0o644))
-	}
-	for _, rel := range []string{"classification.yaml", "raw/r.md", "sessions/s.jsonl", "wiki/w/facts/x.txt", "wiki/w/../../raw/r.md"} {
-		_, _, _, err := api.UpdateNote(brain, api.UpdateNoteOptions{Path: rel, Content: "replaced"})
-		assert.Error(t, err, rel)
-	}
-	for rel, body := range files {
-		if rel == "wiki/w/facts/ok.md" || rel == "knowledge/k.md" {
-			continue
-		}
-		got, err := os.ReadFile(filepath.Join(brain, filepath.FromSlash(rel)))
-		require.NoError(t, err)
-		assert.Equal(t, body, string(got), rel)
-	}
-	for _, rel := range []string{"wiki/w/facts/ok.md", "knowledge/k.md"} {
-		_, _, _, err := api.UpdateNote(brain, api.UpdateNoteOptions{Path: rel, Content: "new body"})
-		require.NoError(t, err, "positive control: %s", rel)
-		got, _ := os.ReadFile(filepath.Join(brain, filepath.FromSlash(rel)))
-		assert.Contains(t, string(got), "new body")
-	}
-}
-
-func TestUpdateNoteDoesNotWriteThroughASymlinkedNote(t *testing.T) {
-	brain := t.TempDir()
-	facts := filepath.Join(brain, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	victim := filepath.Join(brain, "raw", "victim.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "victim.md"), filepath.Join(facts, "l.md")))
-	_, _, _, err := api.UpdateNote(brain, api.UpdateNoteOptions{Path: "wiki/w/facts/l.md", Content: "replaced"})
-	assert.Error(t, err)
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched\n", string(got))
-}
-
-// The note is swapped between a regular file and an in-brain symlink to a
-// raw/ file while UpdateNote runs: the read and the write each refuse a
-// symlink, so the raw/ file is never rewritten.
-func TestUpdateNoteNeverRewritesASymlinkSwappedInForTheNote(t *testing.T) {
-	brain := t.TempDir()
-	facts := filepath.Join(brain, "wiki", "w", "facts")
-	require.NoError(t, os.MkdirAll(facts, 0o755))
-	victim := filepath.Join(brain, "raw", "victim.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	note := filepath.Join(facts, "n.md")
-	body := "---\ntitle: n\n---\nold\n"
-	require.NoError(t, os.WriteFile(note, []byte(body), 0o644))
-
-	var stop atomic.Bool
-	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		tmp := note + ".swap"
-		for i := 0; !stop.Load(); i++ {
-			_ = os.Remove(tmp)
-			if i%2 == 0 {
-				_ = os.WriteFile(tmp, []byte(body), 0o644)
-			} else {
-				_ = os.Symlink(filepath.Join("..", "..", "..", "raw", "victim.md"), tmp)
-			}
-			_ = os.Rename(tmp, note)
-		}
-	}()
-	ok := 0
-	for deadline := time.Now().Add(1500 * time.Millisecond); time.Now().Before(deadline); {
-		if _, _, _, err := api.UpdateNote(brain, api.UpdateNoteOptions{Path: "wiki/w/facts/n.md", Content: "new"}); err == nil {
-			ok++
-		}
-	}
-	stop.Store(true)
-	wg.Wait()
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched\n", string(got))
-	assert.Positive(t, ok, "positive control: some updates reach the regular note")
-}

ingestion/internal/brain/index.go

@@ -2,18 +2,12 @@ package brain
 
 import (
 	"bufio"
-	"bytes"
-	"errors"
 	"fmt"
-	"io"
-	"io/fs"
 	"os"
 	"path/filepath"
 	"sort"
 	"strings"
 	"time"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 )
 
 // noteEntry is one row in a Wing _index.md.
@@ -33,18 +27,13 @@ func BuildWingIndex(brainDir, wing string) error {
 		return fmt.Errorf("invalid wing %q", wing)
 	}
 	wingDir := filepath.Join(brainDir, "wiki", w)
-	// Listed and read through the brain root (hyperguild#157): a wing or
+	if _, err := os.Stat(wingDir); os.IsNotExist(err) {
-	// hall that is a symlink is not followed, and notes are regular files.
-	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
 	}
@@ -69,47 +58,51 @@ func BuildWingIndex(brainDir, wing string) error {
 
 // 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})
 		}
 	}
@@ -124,40 +117,9 @@ func readTitleAndCreated(path, slug string) (string, string) {
 		return slug, ""
 	}
 	defer func() { _ = f.Close() }()
-	title, created := parseTitleAndCreated(f)
-	if created == "" {
-		if info, err := os.Stat(path); err == nil {
-			created = info.ModTime().UTC().Format("2006-01-02")
-		}
-	}
-	return titleOrSlug(title, slug), created
-}
 
-// readTitleAndCreatedIn is readTitleAndCreated through the brain root,
+	title, created := "", ""
-// regular files only (hyperguild#157).
+	scanner := bufio.NewScanner(f)
-func readTitleAndCreatedIn(bfs *brainfs.Brain, rel, slug string) (string, string) {
-	content, err := bfs.ReadRegular(rel)
-	if err != nil {
-		return slug, ""
-	}
-	title, created := parseTitleAndCreated(bytes.NewReader(content))
-	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 {
-	if title == "" {
-		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()
@@ -187,5 +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

@@ -4,12 +4,9 @@ import (
 	"bufio"
 	"fmt"
 	"os"
-	"path"
 	"path/filepath"
 	"strings"
 	"time"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs"
 )
 
 // seeAlsoHeader is the markdown heading used to group cross-wing links.
@@ -200,12 +197,6 @@ func fileExists(p string) bool {
 // section headers. Rejects same-wing pairs (a tunnel is by definition
 // cross-wing) and missing notes.
 func WriteTunnel(brainDir, sourcePath, targetPath string) error {
-	if err := checkNotePath(sourcePath); err != nil {
-		return fmt.Errorf("source: %w", err)
-	}
-	if err := checkNotePath(targetPath); err != nil {
-		return fmt.Errorf("target: %w", err)
-	}
 	srcWing, err := wingOf(sourcePath)
 	if err != nil {
 		return fmt.Errorf("source: %w", err)
@@ -218,50 +209,20 @@ func WriteTunnel(brainDir, sourcePath, targetPath string) error {
 		return fmt.Errorf("tunnel must cross wings; got both in %q", srcWing)
 	}
 
-	// Both notes are read and rewritten through the brain root, regular
+	srcFull := filepath.Join(brainDir, filepath.FromSlash(sourcePath))
-	// files only: brain_tunnel passes caller-supplied paths, and the brain is
+	tgtFull := filepath.Join(brainDir, filepath.FromSlash(targetPath))
-	// a Syncthing folder that can hold symlinks.
+	if _, err := os.Stat(srcFull); err != nil {
-	bfs, err := brainfs.Open(brainDir)
-	if err != nil {
-		return fmt.Errorf("open brain: %w", err)
-	}
-	defer func() { _ = bfs.Close() }()
-	srcContent, err := bfs.ReadRegular(sourcePath)
-	if err != nil {
 		return fmt.Errorf("source note: %w", err)
 	}
-	tgtContent, err := bfs.ReadRegular(targetPath)
+	if _, err := os.Stat(tgtFull); err != nil {
-	if err != nil {
 		return fmt.Errorf("target note: %w", err)
 	}
 
-	if out, changed, err := withSeeAlso(srcContent, wikilinkOf(targetPath)); err != nil {
+	if err := appendSeeAlso(srcFull, wikilinkOf(targetPath)); err != nil {
 		return fmt.Errorf("update source: %w", err)
-	} else if changed {
-		if err := bfs.WriteRegular(sourcePath, out); err != nil {
-			return fmt.Errorf("update source: %w", err)
-		}
 	}
-	if out, changed, err := withSeeAlso(tgtContent, wikilinkOf(sourcePath)); err != nil {
+	if err := appendSeeAlso(tgtFull, wikilinkOf(sourcePath)); err != nil {
 		return fmt.Errorf("update target: %w", err)
-	} else if changed {
-		if err := bfs.WriteRegular(targetPath, out); err != nil {
-			return fmt.Errorf("update target: %w", err)
-		}
-	}
-	return nil
-}
-
-// checkNotePath accepts only a clean, local wiki/<wing>/<hall>/.../<slug>.md
-// path: no "." or ".." segments, no empty segments, no leading slash.
-func checkNotePath(p string) error {
-	if p == "" || path.Clean(p) != p || !filepath.IsLocal(p) || !strings.HasSuffix(p, ".md") {
-		return fmt.Errorf("not a clean wiki note path: %q", p)
-	}
-	for _, part := range strings.Split(p, "/") {
-		if part == "" || part == "." || part == ".." {
-			return fmt.Errorf("not a clean wiki note path: %q", p)
-		}
 	}
 	return nil
 }
@@ -287,13 +248,16 @@ func wingOf(relPath string) (string, error) {
 	return parts[1], nil
 }
 
-// withSeeAlso returns content with `- [[link]]` under its See also section,
+// appendSeeAlso inserts `- [[link]]` under the file's See also section,
-// creating the section if absent. changed is false when the link is already
+// creating the section if absent. No-op when the link is already present.
-// present.
+func appendSeeAlso(filePath, link string) error {
-func withSeeAlso(content []byte, link string) (out []byte, changed bool, err error) {
+	content, err := os.ReadFile(filePath)
+	if err != nil {
+		return err
+	}
 	wikilink := "[[" + link + "]]"
 	if strings.Contains(string(content), wikilink) {
-		return content, false, nil
+		return nil
 	}
 
 	bullet := "- " + wikilink
@@ -302,7 +266,8 @@ func withSeeAlso(content []byte, link string) (out []byte, changed bool, err err
 		// No section yet — append a fresh one. Always emit a trailing
 		// newline so subsequent appends don't merge into the previous line.
 		trimmed := strings.TrimRight(string(content), "\n")
-		return []byte(trimmed + "\n\n" + seeAlsoHeader + "\n\n" + bullet + "\n"), true, nil
+		out := trimmed + "\n\n" + seeAlsoHeader + "\n\n" + bullet + "\n"
+		return os.WriteFile(filePath, []byte(out), 0o644)
 	}
 
 	// Section exists — splice the bullet in just before the next `## `
@@ -328,11 +293,12 @@ func withSeeAlso(content []byte, link string) (out []byte, changed bool, err err
 		b.WriteByte('\n')
 	}
 	if err := scanner.Err(); err != nil {
-		return nil, false, err
+		return err
 	}
 	if !inserted {
 		// section was the last thing in the file — just append bullet
-		return []byte(strings.TrimRight(b.String(), "\n") + "\n" + bullet + "\n"), true, nil
+		out := strings.TrimRight(b.String(), "\n") + "\n" + bullet + "\n"
+		return os.WriteFile(filePath, []byte(out), 0o644)
 	}
-	return []byte(b.String()), true, nil
+	return os.WriteFile(filePath, []byte(b.String()), 0o644)
 }

ingestion/internal/brain/tunnel_root_test.go

@@ -1,141 +0,0 @@
-package brain_test
-
-import (
-	"os"
-	"path/filepath"
-	"strings"
-	"sync"
-	"sync/atomic"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-
-	"github.com/mathiasbq/hyperguild/ingestion/internal/brain"
-)
-
-// brain_tunnel passes caller-supplied source and target paths to WriteTunnel,
-// which checked only "wiki/<wing>/..." and then joined them onto the brain
-// dir: ".." segments resolved outside the brain and appendSeeAlso rewrote the
-// file there.
-func TestWriteTunnelRefusesATargetThatTraversesOutOfTheBrain(t *testing.T) {
-	brain0 := t.TempDir()
-	src := filepath.Join(brain0, "wiki", "a", "facts", "s.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(src), 0o755))
-	require.NoError(t, os.WriteFile(src, []byte("---\ntitle: S\n---\nbody\n"), 0o644))
-	victim := filepath.Join(t.TempDir(), "victim.md")
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-
-	up := strings.Repeat("../", strings.Count(filepath.Clean(brain0), "/")+3)
-	target := "wiki/b/x/" + up + strings.TrimPrefix(victim, "/")
-	err := brain.WriteTunnel(brain0, "wiki/a/facts/s.md", target)
-	assert.Error(t, err)
-	got, rerr := os.ReadFile(victim)
-	require.NoError(t, rerr)
-	assert.Equal(t, "untouched\n", string(got), "a file outside the brain was modified")
-}
-
-func TestWriteTunnelRefusesUncleanOrNonWikiPaths(t *testing.T) {
-	brain0 := t.TempDir()
-	for _, p := range []string{"wiki/a/facts/s.md", "wiki/b/facts/t.md", "wiki/b/facts/t.txt", "raw/r.md"} {
-		require.NoError(t, os.MkdirAll(filepath.Dir(filepath.Join(brain0, p)), 0o755))
-		require.NoError(t, os.WriteFile(filepath.Join(brain0, p), []byte("x\n"), 0o644))
-	}
-	for _, target := range []string{
-		"wiki/b/facts/../../../raw/r.md",
-		"wiki/b/./facts/t.md",
-		"wiki/b//facts/t.md",
-		"/wiki/b/facts/t.md",
-		"wiki/b/facts/t.txt",
-		"wiki/b/facts/",
-	} {
-		assert.Error(t, brain.WriteTunnel(brain0, "wiki/a/facts/s.md", target), target)
-	}
-	for _, p := range []string{"raw/r.md", "wiki/b/facts/t.txt"} {
-		got, err := os.ReadFile(filepath.Join(brain0, p))
-		require.NoError(t, err)
-		assert.Equal(t, "x\n", string(got), p)
-	}
-	require.NoError(t, brain.WriteTunnel(brain0, "wiki/a/facts/s.md", "wiki/b/facts/t.md"), "positive control")
-	got, err := os.ReadFile(filepath.Join(brain0, "wiki", "b", "facts", "t.md"))
-	require.NoError(t, err)
-	assert.Contains(t, string(got), "[[a/facts/s]]")
-}
-
-func TestWriteTunnelDoesNotWriteThroughASymlinkedNote(t *testing.T) {
-	brain0 := t.TempDir()
-	src := filepath.Join(brain0, "wiki", "a", "facts", "s.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(src), 0o755))
-	require.NoError(t, os.WriteFile(src, []byte("x\n"), 0o644))
-	tdir := filepath.Join(brain0, "wiki", "b", "facts")
-	require.NoError(t, os.MkdirAll(tdir, 0o755))
-	victim := filepath.Join(t.TempDir(), "victim.md")
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	require.NoError(t, os.Symlink(victim, filepath.Join(tdir, "t.md")))
-	assert.Error(t, brain.WriteTunnel(brain0, "wiki/a/facts/s.md", "wiki/b/facts/t.md"))
-	got, err := os.ReadFile(victim)
-	require.NoError(t, err)
-	assert.Equal(t, "untouched\n", string(got))
-
-	// The same with a link to a file elsewhere in the brain, which os.Root
-	// would follow.
-	inVictim := filepath.Join(brain0, "raw", "v.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(inVictim), 0o755))
-	require.NoError(t, os.WriteFile(inVictim, []byte("untouched\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "v.md"), filepath.Join(tdir, "u.md")))
-	assert.Error(t, brain.WriteTunnel(brain0, "wiki/a/facts/s.md", "wiki/b/facts/u.md"))
-	got, err = os.ReadFile(inVictim)
-	require.NoError(t, err)
-	assert.Equal(t, "untouched\n", string(got))
-	got, err = os.ReadFile(src)
-	require.NoError(t, err)
-	assert.Equal(t, "x\n", string(got), "the source is not touched when the target is refused")
-}
-
-// The target is swapped between a regular note and a symlink to an in-brain
-// file outside wiki/ while WriteTunnel runs: the read and the write each
-// refuse a symlink, so the other file is never rewritten.
-func TestWriteTunnelNeverRewritesASymlinkSwappedInForTheTarget(t *testing.T) {
-	brain0 := t.TempDir()
-	src := filepath.Join(brain0, "wiki", "a", "facts", "s.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(src), 0o755))
-	require.NoError(t, os.WriteFile(src, []byte("x\n"), 0o644))
-	tdir := filepath.Join(brain0, "wiki", "b", "facts")
-	require.NoError(t, os.MkdirAll(tdir, 0o755))
-	victim := filepath.Join(brain0, "raw", "victim.md")
-	require.NoError(t, os.MkdirAll(filepath.Dir(victim), 0o755))
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	tgt := filepath.Join(tdir, "t.md")
-	require.NoError(t, os.WriteFile(tgt, []byte("t\n"), 0o644))
-
-	var stop atomic.Bool
-	var wg sync.WaitGroup
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		tmp := tgt + ".swap"
-		for i := 0; !stop.Load(); i++ {
-			_ = os.Remove(tmp)
-			if i%2 == 0 {
-				_ = os.WriteFile(tmp, []byte("t\n"), 0o644)
-			} else {
-				_ = os.Symlink(filepath.Join("..", "..", "..", "raw", "victim.md"), tmp)
-			}
-			_ = os.Rename(tmp, tgt)
-		}
-	}()
-	ok := 0
-	for deadline := time.Now().Add(1500 * time.Millisecond); time.Now().Before(deadline); {
-		if brain.WriteTunnel(brain0, "wiki/a/facts/s.md", "wiki/b/facts/t.md") == nil {
-			ok++
-		}
-		_ = os.WriteFile(src, []byte("x\n"), 0o644)
-	}
-	stop.Store(true)
-	wg.Wait()
-	got, err := os.ReadFile(victim)
-	require.NoError(t, err)
-	assert.Equal(t, "untouched\n", string(got), "the swapped-in symlink's target was rewritten")
-	assert.Positive(t, ok, "positive control: some tunnels were written to the regular target")
-}

ingestion/internal/brainfs/brainfs.go

@@ -104,27 +104,6 @@ func (b *Brain) ReadDirRegular(relDir string) ([]string, error) {
 	return names, 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
-}
-
 // 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) {
@@ -249,41 +228,3 @@ 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. Intermediate in-brain symlinks are still followed (os.Root keeps
-// the write inside the brain; hyperguild#167).
-func (b *Brain) WriteRegular(rel string, data []byte) error {
-	rel = filepath.ToSlash(rel)
-	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

@@ -262,67 +262,3 @@ func TestReadRegularNeverReturnsAnInBrainFileSwappedInBehindASymlink(t *testing.
 	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")
-	require.NoError(t, os.WriteFile(outside, []byte("untouched"), 0o644))
-	require.NoError(t, os.Symlink(outside, filepath.Join(dir, "l.md")))
-	require.NoError(t, syscall.Mkfifo(filepath.Join(dir, "f.md"), 0o644))
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "n.md"), []byte("old content"), 0o644))
-	b, err := Open(dir)
-	require.NoError(t, err)
-	defer func() { _ = b.Close() }()
-
-	assert.Error(t, b.WriteRegular("l.md", []byte("x")))
-	got, _ := os.ReadFile(outside)
-	assert.Equal(t, "untouched", string(got))
-
-	// A symlink to another file inside the brain: os.Root would allow it,
-	// only O_NOFOLLOW refuses it.
-	require.NoError(t, os.WriteFile(filepath.Join(dir, "in.md"), []byte("inside"), 0o644))
-	require.NoError(t, os.Symlink("in.md", filepath.Join(dir, "il.md")))
-	assert.Error(t, b.WriteRegular("il.md", []byte("x")))
-	got, _ = os.ReadFile(filepath.Join(dir, "in.md"))
-	assert.Equal(t, "inside", string(got))
-
-	// A reader held open, so a non-blocking write open would succeed. The
-	// Lstat type check refuses the FIFO first; the handle check and
-	// O_NONBLOCK matter only if it is swapped in after the Lstat.
-	r, err := os.OpenFile(filepath.Join(dir, "f.md"), os.O_RDONLY|syscall.O_NONBLOCK, 0)
-	require.NoError(t, err)
-	defer func() { _ = r.Close() }()
-	done := make(chan error, 1)
-	go func() { done <- b.WriteRegular("f.md", []byte("x")) }()
-	select {
-	case err := <-done:
-		assert.Error(t, err)
-	case <-time.After(3 * time.Second):
-		t.Fatal("WriteRegular hung on a FIFO")
-	}
-
-	assert.Error(t, b.WriteRegular("../"+filepath.Base(filepath.Dir(outside))+"/o.md", []byte("x")))
-	assert.Error(t, b.WriteRegular("missing.md", []byte("x")), "does not create files")
-
-	require.NoError(t, b.WriteRegular("n.md", []byte("new")))
-	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)
-}

ingestion/internal/brainfs/brainfstest/brainfstest.go

@@ -27,7 +27,7 @@ const outsideContent = "---\ntitle: " + Sentinel + "\naliases:\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 {
@@ -42,12 +42,9 @@ var swapSeq atomic.Int64
 // 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)
@@ -70,26 +67,22 @@ 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(link, 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
@@ -114,41 +107,18 @@ func AssertNoLeak(t *testing.T, path, inside string, d time.Duration, read func(
 	AssertNoLeakFrom(t, path, inside, Outside(t), d, read)
 }
 
-// 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.
-//
+func AssertNoLeakFrom(t *testing.T, path, inside, target string, d time.Duration, read func() string) {
-// 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) {
+	StartSwap(t, path, inside, target, false)
-		t.Fatalf("inside content must contain %q", InsideMarker)
+	leaks, iters := 0, 0
-	}
-	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("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)
-	}
 }
 
 // AssertNoHang loops read for d while a FIFO swapper (held writers) runs on

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/pipeline/root_test.go

@@ -162,6 +162,6 @@ func TestBackfillRefsDoesNotCopyAPageSwappedInBehindASymlink(t *testing.T) {
 		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")
+	require.Contains(t, read(), "zqinside", "positive control: the regular page gets the ref")
 	brainfstest.AssertNoLeakFrom(t, page, inside, target, 3*time.Second, read)
 }

ingestion/internal/search/brainroot_test.go

@@ -93,20 +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
@@ -119,46 +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) {

ingestion/internal/session/id_test.go

@@ -1,92 +0,0 @@
-package session
-
-import (
-	"errors"
-	"os"
-	"path/filepath"
-	"syscall"
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-)
-
-// session_log passed the caller's session_id straight into
-// filepath.Join(sessionsDir, id+".jsonl") and opened it O_CREATE|O_APPEND:
-// path segments in the id created or appended files anywhere the pod could
-// write. The id is now a plain name, and the open does not follow a final
-// symlink.
-func TestAppendRefusesSessionIDsThatAreNotPlainNames(t *testing.T) {
-	root := t.TempDir()
-	dir := filepath.Join(root, "sessions")
-	for _, id := range []string{"../x", "a/b", "/abs", ".", "..", ".hidden", "", "a\\b", "a\x00b"} {
-		assert.Error(t, Append(dir, id, Entry{SessionID: id}), "%q", id)
-	}
-	ents, _ := os.ReadDir(root)
-	for _, e := range ents {
-		assert.Equal(t, "sessions", e.Name(), "nothing created beside the sessions dir")
-	}
-	for _, id := range []string{"1557b2e1-bf0d-5c4f-bbe3-0754d087e356", "_routing", "2026-05-05-infra.plan", "0"} {
-		require.NoError(t, Append(dir, id, Entry{SessionID: id}), "positive control: %q", id)
-	}
-}
-
-func TestAppendDoesNotWriteThroughASymlinkedLog(t *testing.T) {
-	root := t.TempDir()
-	dir := filepath.Join(root, "sessions")
-	require.NoError(t, os.MkdirAll(dir, 0o755))
-	victim := filepath.Join(root, "victim.md")
-	require.NoError(t, os.WriteFile(victim, []byte("untouched\n"), 0o644))
-	require.NoError(t, os.Symlink(filepath.Join("..", "victim.md"), filepath.Join(dir, "s.jsonl")))
-	assert.Error(t, Append(dir, "s", Entry{SessionID: "s"}))
-	got, _ := os.ReadFile(victim)
-	assert.Equal(t, "untouched\n", string(got))
-}
-
-func TestReadRefusesSessionIDsThatAreNotPlainNames(t *testing.T) {
-	root := t.TempDir()
-	require.NoError(t, os.WriteFile(filepath.Join(root, "x.jsonl"), []byte(`{"session_id":"x"}`+"\n"), 0o644))
-	_, 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")
-	}
-}

ingestion/internal/session/session.go

@@ -9,8 +9,6 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
-	"regexp"
-	"syscall"
 	"time"
 )
 
@@ -44,32 +42,13 @@ type Attempt struct {
 	RunnerOutput  string `json:"runner_output,omitempty"`
 }
 
-// idPattern is a plain file name: session_log takes the id from the caller,
-// and a path segment in it created or appended files anywhere the pod could
-// 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 nil
-}
-
 // Append writes entry as a single JSON line to sessionsDir/{sessionID}.jsonl.
-// The open does not follow a final symlink.
 func Append(sessionsDir, sessionID string, entry Entry) error {
-	if err := checkID(sessionID); err != nil {
-		return err
-	}
 	if err := os.MkdirAll(sessionsDir, 0o755); err != nil {
 		return fmt.Errorf("create sessions dir: %w", err)
 	}
 	path := filepath.Join(sessionsDir, sessionID+".jsonl")
-	f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY|syscall.O_NOFOLLOW|syscall.O_NONBLOCK, 0o644)
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
 	if err != nil {
 		return fmt.Errorf("open session log: %w", err)
 	}
@@ -91,9 +70,6 @@ func Append(sessionsDir, sessionID string, entry Entry) error {
 
 // Read returns all entries for sessionID. Returns empty slice if no log exists.
 func Read(sessionsDir, sessionID string) ([]Entry, error) {
-	if err := checkID(sessionID); err != nil {
-		return nil, err
-	}
 	path := filepath.Join(sessionsDir, sessionID+".jsonl")
 	f, err := os.Open(path)
 	if errors.Is(err, fs.ErrNotExist) {

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)")
-}