fix(workflow_run_trigger): 204 dispatch is success; resolve run via listing (#41)

Gitea's workflow_dispatch endpoint returns 204 No Content with no Location
header. DispatchWorkflow required that header, so every successful dispatch
errored with "missing Location header" and never yielded a run ID — making
the tool unusable for CAD dispatch.

- DispatchWorkflow now returns error-only; 204 = success, no Location needed.
  Body already carried ref+inputs; kept and covered by test.
- Tool snapshots the newest existing workflow_dispatch run before dispatch,
  then polls ListWorkflowRuns after and returns the newest run with ID above
  that baseline (avoids returning a stale prior run). Falls back to an honest
  "dispatched, run not yet registered" result rather than failing.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/tools/workflow_run_trigger.go

@@ -4,12 +4,22 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"time"
 
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/allowlist"
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
 	"gitea.d-ma.be/mathias/gitea-mcp/internal/registry"
 )
 
+// dispatchResolveBudget bounds how many times we poll for the dispatched run to
+// appear, and dispatchResolvePoll is the gap between polls. Gitea returns 204
+// with no run ID, so we list workflow_dispatch runs and take the newest above
+// the pre-dispatch baseline; it may register a beat after the 204.
+const (
+	dispatchResolveBudget = 5
+	dispatchResolvePoll   = time.Second
+)
+
 // WorkflowRunTrigger triggers a Gitea Actions workflow_dispatch run.
 type WorkflowRunTrigger struct {
 	c       *gitea.Client
@@ -68,17 +78,82 @@ func (t *WorkflowRunTrigger) Call(ctx context.Context, raw json.RawMessage) (jso
 		}
 	}
 
-	result, err := t.c.DispatchWorkflow(ctx, args.Owner, args.Name, args.Workflow, gitea.DispatchWorkflowArgs{
+	// Snapshot the newest existing workflow_dispatch run BEFORE dispatching, so we
+	// can tell our fresh run apart from a prior one (Gitea's 204 carries no run ID).
+	baseline := t.newestDispatchRunID(ctx, args.Owner, args.Name, args.Workflow, ref)
+
+	if err := t.c.DispatchWorkflow(ctx, args.Owner, args.Name, args.Workflow, gitea.DispatchWorkflowArgs{
 		Ref:    ref,
 		Inputs: args.Inputs,
-	})
-	if err != nil {
+	}); err != nil {
 		return nil, err
 	}
 
-	htmlURL := fmt.Sprintf("%s/%s/%s/actions/runs/%d", t.baseURL, args.Owner, args.Name, result.RunID)
+	// Resolve the new run by listing workflow_dispatch runs and taking the newest
+	// one whose ID exceeds the baseline. Poll briefly: the run can register a beat
+	// after the 204.
+	var run *gitea.WorkflowRun
+	for i := 0; i < dispatchResolveBudget; i++ {
+		if i > 0 {
+			select {
+			case <-ctx.Done():
+				return nil, ctx.Err()
+			case <-time.After(dispatchResolvePoll):
+			}
+		}
+		if r := t.newestDispatchRun(ctx, args.Owner, args.Name, args.Workflow, ref); r != nil && r.ID > baseline {
+			run = r
+			break
+		}
+	}
+
+	// Dispatch succeeded (204). If the run has not surfaced yet, say so honestly
+	// rather than failing — the workflow IS firing; the caller can list runs.
+	if run == nil {
+		return textOK(map[string]any{
+			"dispatched": true,
+			"note": "dispatch accepted but the run did not register within the resolve window; " +
+				"list recent workflow_dispatch runs to find it",
+		})
+	}
+
+	htmlURL := run.HTMLURL
+	if htmlURL == "" {
+		htmlURL = fmt.Sprintf("%s/%s/%s/actions/runs/%d", t.baseURL, args.Owner, args.Name, run.ID)
+	}
 	return textOK(map[string]any{
-		"run_id":   result.RunID,
-		"html_url": htmlURL,
+		"dispatched": true,
+		"run_id":     run.ID,
+		"html_url":   htmlURL,
 	})
 }
+
+// newestDispatchRun returns the most recent workflow_dispatch run for the given
+// workflow and ref, or nil if none / on listing error (best-effort resolution).
+func (t *WorkflowRunTrigger) newestDispatchRun(ctx context.Context, owner, name, workflow, ref string) *gitea.WorkflowRun {
+	resp, err := t.c.ListWorkflowRuns(ctx, owner, name, gitea.ListWorkflowRunsArgs{
+		Event:    "workflow_dispatch",
+		Workflow: workflow,
+		Branch:   ref,
+		Limit:    20,
+	})
+	if err != nil || resp == nil {
+		return nil
+	}
+	var newest *gitea.WorkflowRun
+	for i := range resp.WorkflowRuns {
+		r := &resp.WorkflowRuns[i]
+		if newest == nil || r.ID > newest.ID {
+			newest = r
+		}
+	}
+	return newest
+}
+
+// newestDispatchRunID is newestDispatchRun's ID, or 0 if none.
+func (t *WorkflowRunTrigger) newestDispatchRunID(ctx context.Context, owner, name, workflow, ref string) int64 {
+	if r := t.newestDispatchRun(ctx, owner, name, workflow, ref); r != nil {
+		return r.ID
+	}
+	return 0
+}