fix: update DB task status in writeBlockerPlaceholder for execute-task (#2657)

writeBlockerPlaceholder writes a placeholder SUMMARY file when idle
recovery exhausts all retries, but never updated the DB task status.
verifyExpectedArtifact checks the DB as the authoritative source for
execute-task units — with status still "pending", verification failed,
deriveState re-derived the same task, and the dispatch loop repeated
indefinitely (observed as 8-9 "Advancing pipeline" messages).

After writing the file, call updateTaskStatus to mark the task as
"complete" in the DB. This lets verifyExpectedArtifact pass and
breaks the infinite re-dispatch loop.

Closes #2531

src/resources/extensions/gsd/auto-recovery.ts

@@ -12,7 +12,7 @@ import { parseUnitId } from "./unit-id.js";
 import { atomicWriteSync } from "./atomic-write.js";
 import { clearParseCache } from "./files.js";
 import { parseRoadmap as parseLegacyRoadmap, parsePlan as parseLegacyPlan } from "./parsers-legacy.js";
-import { isDbAvailable, getTask, getSlice, getSliceTasks } from "./gsd-db.js";
+import { isDbAvailable, getTask, getSlice, getSliceTasks, updateTaskStatus } from "./gsd-db.js";
 import { isValidationTerminal } from "./state.js";
 import {
   nativeConflictFiles,
@@ -425,6 +425,20 @@ export function writeBlockerPlaceholder(
     `Review and replace this file before relying on downstream artifacts.`,
   ].join("\n");
   writeFileSync(absPath, content, "utf-8");
+
+  // Mark the task as complete in the DB so verifyExpectedArtifact passes.
+  // Without this, the DB status stays "pending" and the dispatch loop
+  // re-derives the same task indefinitely (#2531).
+  if (unitType === "execute-task" && isDbAvailable()) {
+    const parts = unitId.split("/");
+    const mid = parts[0];
+    const sid = parts[1];
+    const tid = parts[2];
+    if (mid && sid && tid) {
+      try { updateTaskStatus(mid, sid, tid, "complete", new Date().toISOString()); } catch { /* non-fatal */ }
+    }
+  }
+
   return diagnoseExpectedArtifact(unitType, unitId, base);
 }
 

src/resources/extensions/gsd/tests/idle-recovery.test.ts

@@ -294,3 +294,66 @@ test('verifyExpectedArtifact: hook types always return true', () => {
   }
 });
 
+
+test('writeBlockerPlaceholder: updates DB task status for execute-task (#2531)', async () => {
+  const base = createFixtureBase();
+  try {
+    const { openDatabase, closeDatabase, insertMilestone, insertSlice, insertTask, getTask, isDbAvailable } =
+      await import("../gsd-db.ts");
+
+    const dbPath = join(base, ".gsd", "gsd.db");
+    // Create the tasks directory (required for artifact path resolution)
+    mkdirSync(join(base, ".gsd", "milestones", "M001", "slices", "S01", "tasks"), { recursive: true });
+
+    openDatabase(dbPath);
+    try {
+      insertMilestone({ id: "M001", title: "Test", status: "active" });
+      insertSlice({ id: "S01", milestoneId: "M001", title: "Slice", status: "active" });
+      insertTask({ id: "T01", sliceId: "S01", milestoneId: "M001", title: "Task", status: "pending" });
+
+      // Before fix: writeBlockerPlaceholder wrote the file but left DB as "pending"
+      writeBlockerPlaceholder("execute-task", "M001/S01/T01", base, "idle recovery exhausted");
+
+      const task = getTask("M001", "S01", "T01");
+      assert.equal(task?.status, "complete",
+        "writeBlockerPlaceholder must update DB task status to 'complete' so verifyExpectedArtifact passes");
+
+      // Verify the full chain works: verifyExpectedArtifact should return true
+      const verified = verifyExpectedArtifact("execute-task", "M001/S01/T01", base);
+      assert.equal(verified, true,
+        "verifyExpectedArtifact should pass after writeBlockerPlaceholder updates DB status");
+    } finally {
+      if (isDbAvailable()) closeDatabase();
+    }
+  } finally {
+    cleanup(base);
+  }
+});
+
+test('writeBlockerPlaceholder: does NOT update DB for non-execute-task types', async () => {
+  const base = createFixtureBase();
+  try {
+    const { openDatabase, closeDatabase, insertMilestone, insertSlice, getSlice, isDbAvailable } =
+      await import("../gsd-db.ts");
+
+    const dbPath = join(base, ".gsd", "gsd.db");
+    mkdirSync(join(base, ".gsd", "milestones", "M001", "slices", "S01"), { recursive: true });
+
+    openDatabase(dbPath);
+    try {
+      insertMilestone({ id: "M001", title: "Test", status: "active" });
+      insertSlice({ id: "S01", milestoneId: "M001", title: "Slice", status: "active" });
+
+      // research-slice is NOT execute-task — DB should NOT be updated
+      writeBlockerPlaceholder("research-slice", "M001/S01", base, "idle recovery exhausted");
+
+      const slice = getSlice("M001", "S01");
+      assert.equal(slice?.status, "active",
+        "writeBlockerPlaceholder should not change DB status for non-execute-task types");
+    } finally {
+      if (isDbAvailable()) closeDatabase();
+    }
+  } finally {
+    cleanup(base);
+  }
+});