fix(FN-6086): preserve merge-queued review tasks

Treat persisted merge queue ownership as an active merge-lane owner when hydrating in-review stall state and when self-healing scans for ghost, stalled, or completion-handoff-limbo tasks.

Also clear false completion-handoff exhaustion for tasks that are still owned by the merge queue so previously poisoned review tasks can continue merging.

Fusion-Task-Id: FN-6086

packages/core/src/__tests__/store-in-review-stall.test.ts

@@ -52,6 +52,27 @@ describe("TaskStore inReviewStall hydration", () => {
     expect(task?.inReviewStall?.reason).toContain("no active merger");
   });
 
+  it("omits merge-stalled hydration while the task is already queued for merge", async () => {
+    await seedTask("FN-6088", {});
+    await store.enqueueMergeQueue("FN-6088");
+
+    const listed = (await store.listTasks({ slim: true })).find((entry) => entry.id === "FN-6088");
+    expect(listed?.inReviewStall).toBeUndefined();
+    expect(listed?.inReviewStalled).toBeUndefined();
+
+    const detailed = await store.getTask("FN-6088");
+    expect(detailed.inReviewStall).toBeUndefined();
+    expect(detailed.inReviewStalled).toBeUndefined();
+
+    const modified = (await store.listTasksModifiedSince("1970-01-01T00:00:00.000Z")).tasks.find((entry) => entry.id === "FN-6088");
+    expect(modified?.inReviewStall).toBeUndefined();
+    expect(modified?.inReviewStalled).toBeUndefined();
+
+    const searched = (await store.searchTasks("FN-6088", { slim: true })).find((entry) => entry.id === "FN-6088");
+    expect(searched?.inReviewStall).toBeUndefined();
+    expect(searched?.inReviewStalled).toBeUndefined();
+  });
+
   it("omits inReviewStall for paused in-review task", async () => {
     await seedTask("FN-4217-PAUSED", { paused: true });
 

packages/core/src/store.ts

@@ -2738,6 +2738,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
     return this.rowToTask(row);
   }
 
+  private getMergeQueuedTaskIds(): Set<string> {
+    const rows = this.db.prepare("SELECT taskId FROM mergeQueue").all() as Array<{ taskId: string }>;
+    return new Set(rows.map((row) => row.taskId));
+  }
+
   private isTaskIdPresentInArchivedTasksTable(id: string): boolean {
     try {
       const row = this.db.prepare("SELECT 1 as found FROM archivedTasks WHERE id = ? LIMIT 1").get(id) as { found?: number } | undefined;
@@ -4808,7 +4813,27 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
         };
       }
 
-      task.stalledReview = detectStalledReview(task, { now: Date.now() });
+      const now = Date.now();
+      const settings = await this.getSettingsFast();
+      const mergeQueuedTaskIds = this.getMergeQueuedTaskIds();
+      task.inReviewStall = mergeQueuedTaskIds.has(task.id)
+        ? undefined
+        : getInReviewStallReason(task, {
+          now,
+          autoMerge: allowsAutoMergeProcessing(task, settings),
+          engineActiveSinceMs: settings.engineActiveSinceMs,
+          engineActivationGraceMs: settings.engineActivationGraceMs,
+        });
+      task.inReviewStalled = mergeQueuedTaskIds.has(task.id)
+        ? undefined
+        : getInReviewStalledSignal(task, {
+          now,
+          thresholdMs: settings.inReviewStalledThresholdMs,
+          autoMerge: allowsAutoMergeProcessing(task, settings),
+          engineActiveSinceMs: settings.engineActiveSinceMs,
+          engineActivationGraceMs: settings.engineActivationGraceMs,
+        });
+      task.stalledReview = detectStalledReview(task, { now });
       // Derived at read time only; retrySummary is never persisted to SQLite.
       task.retrySummary = computeRetrySummary(task);
 
@@ -5311,9 +5336,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
       inReviewCriticalMs: settings.staleInReviewCriticalMs,
     };
     let disableAgeStalenessHydration = false;
+    const mergeQueuedTaskIds = this.getMergeQueuedTaskIds();
     const activeTasks = await Promise.all((rows as unknown as TaskRow[]).map(async (row) => {
       const task = this.rowToTask(row);
-      task.inReviewStall = getInReviewStallReason(task, {
+      const isMergeQueued = mergeQueuedTaskIds.has(task.id);
+      task.inReviewStall = isMergeQueued ? undefined : getInReviewStallReason(task, {
         now,
         autoMerge: allowsAutoMergeProcessing(task, settings),
         engineActiveSinceMs: settings.engineActiveSinceMs,
@@ -5325,7 +5352,7 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
         engineActiveSinceMs: settings.engineActiveSinceMs,
         engineActivationGraceMs: settings.engineActivationGraceMs,
       });
-      task.inReviewStalled = getInReviewStalledSignal(task, {
+      task.inReviewStalled = isMergeQueued ? undefined : getInReviewStalledSignal(task, {
         now,
         thresholdMs: settings.inReviewStalledThresholdMs,
         autoMerge: allowsAutoMergeProcessing(task, settings),
@@ -5831,9 +5858,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
       inReviewCriticalMs: settings.staleInReviewCriticalMs,
     };
     let disableAgeStalenessHydration = false;
+    const mergeQueuedTaskIds = this.getMergeQueuedTaskIds();
     const tasks = rows.slice(0, resolvedLimit).map((row) => {
       const task = this.rowToTask(row);
-      task.inReviewStall = getInReviewStallReason(task, {
+      const isMergeQueued = mergeQueuedTaskIds.has(task.id);
+      task.inReviewStall = isMergeQueued ? undefined : getInReviewStallReason(task, {
         now,
         autoMerge: allowsAutoMergeProcessing(task, settings),
         engineActiveSinceMs: settings.engineActiveSinceMs,
@@ -5845,7 +5874,7 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
         engineActiveSinceMs: settings.engineActiveSinceMs,
         engineActivationGraceMs: settings.engineActivationGraceMs,
       });
-      task.inReviewStalled = getInReviewStalledSignal(task, {
+      task.inReviewStalled = isMergeQueued ? undefined : getInReviewStalledSignal(task, {
         now,
         thresholdMs: settings.inReviewStalledThresholdMs,
         autoMerge: allowsAutoMergeProcessing(task, settings),
@@ -5994,9 +6023,11 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
       inReviewCriticalMs: settings.staleInReviewCriticalMs,
     };
     let disableAgeStalenessHydration = false;
+    const mergeQueuedTaskIds = this.getMergeQueuedTaskIds();
     const activeMatches = await Promise.all(rows.map(async (row) => {
       const task = this.rowToTask(row);
-      task.inReviewStall = getInReviewStallReason(task, {
+      const isMergeQueued = mergeQueuedTaskIds.has(task.id);
+      task.inReviewStall = isMergeQueued ? undefined : getInReviewStallReason(task, {
         now,
         autoMerge: allowsAutoMergeProcessing(task, settings),
         engineActiveSinceMs: settings.engineActiveSinceMs,
@@ -6008,7 +6039,7 @@ ${TASK_UPSERT_SQL_ASSIGNMENTS}
         engineActiveSinceMs: settings.engineActiveSinceMs,
         engineActivationGraceMs: settings.engineActivationGraceMs,
       });
-      task.inReviewStalled = getInReviewStalledSignal(task, {
+      task.inReviewStalled = isMergeQueued ? undefined : getInReviewStalledSignal(task, {
         now,
         thresholdMs: settings.inReviewStalledThresholdMs,
         autoMerge: allowsAutoMergeProcessing(task, settings),

packages/engine/src/__tests__/reliability-interactions/completion-handoff-limbo.test.ts

@@ -22,7 +22,7 @@ function doneMarker(minutesAgo = 6) {
   return { action: "Task marked done by agent", timestamp: new Date(Date.now() - minutesAgo * 60_000).toISOString() } as any;
 }
 
-function createStore(task: Task) {
+function createStore(task: Task, mergeQueuedTaskIds: string[] = []) {
   let current = { ...task } as Task;
   return {
     getSettings: vi.fn(async () => ({ globalPause: false, enginePaused: false })),
@@ -33,6 +33,16 @@ function createStore(task: Task) {
     }),
     moveTask: vi.fn(async () => undefined),
     enqueueMergeQueue: vi.fn(async () => undefined),
+    peekMergeQueue: vi.fn(() => mergeQueuedTaskIds.map((taskId) => ({
+      taskId,
+      enqueuedAt: new Date().toISOString(),
+      priority: "normal",
+      leasedBy: null,
+      leasedAt: null,
+      leaseExpiresAt: null,
+      attemptCount: 0,
+      lastError: null,
+    }))),
     logEntry: vi.fn(async () => undefined),
     recordRunAuditEvent: vi.fn(async () => undefined),
     _get: () => current,
@@ -167,19 +177,42 @@ describe("FN-4999 reliability interactions: completion-handoff-limbo", () => {
   });
 
   it("skips tasks already held by the merge queue without incrementing the count", async () => {
-    const store = createStore(limboTask({ completionHandoffLimboRecoveryCount: 1 }));
+    const store = createStore(limboTask({ completionHandoffLimboRecoveryCount: 1 }), ["FN-4999-T"]);
     const requeueForAutoMerge = vi.fn(() => false);
     const manager = new SelfHealingManager(store, { rootDir: "/repo", requeueForAutoMerge });
 
     await manager.recoverCompletionHandoffLimbo();
     await manager.recoverCompletionHandoffLimbo();
 
-    expect(requeueForAutoMerge).toHaveBeenCalledTimes(2);
+    expect(requeueForAutoMerge).not.toHaveBeenCalled();
+    expect(store.enqueueMergeQueue).not.toHaveBeenCalled();
     expect(store._get().completionHandoffLimboRecoveryCount).toBe(1);
     expect(store._get().status).toBeUndefined();
     expect(store.logEntry).not.toHaveBeenCalled();
   });
 
+  it("clears false handoff exhaustion for tasks already held by the merge queue", async () => {
+    const store = createStore(limboTask({
+      status: "failed",
+      error: "Completion handoff limbo recovery exhausted",
+      completionHandoffLimboRecoveryCount: MAX_COMPLETION_HANDOFF_LIMBO_RECOVERIES,
+    }), ["FN-4999-T"]);
+    const requeueForAutoMerge = vi.fn(() => false);
+    const manager = new SelfHealingManager(store, { rootDir: "/repo", requeueForAutoMerge });
+
+    await manager.recoverCompletionHandoffLimbo();
+
+    expect(requeueForAutoMerge).not.toHaveBeenCalled();
+    expect(store.enqueueMergeQueue).not.toHaveBeenCalled();
+    expect(store._get().status).toBeNull();
+    expect(store._get().error).toBeNull();
+    expect(store._get().completionHandoffLimboRecoveryCount).toBe(0);
+    expect(store.logEntry).toHaveBeenCalledWith(
+      "FN-4999-T",
+      "Auto-recovered: cleared false completion-handoff exhaustion while task is already owned by merge queue",
+    );
+  });
+
   it("exhausts only after three accepted limbo recoveries", async () => {
     const store = createStore(limboTask());
     const manager = new SelfHealingManager(store, { rootDir: "/repo", requeueForAutoMerge: vi.fn(() => true) });

packages/engine/src/__tests__/reliability-interactions/in-review-stalled-detector.test.ts

@@ -3,7 +3,7 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import type { Task, TaskStore } from "@fusion/core";
 import { SelfHealingManager } from "../../self-healing.js";
 
-function createStore(task: Task, settings: Record<string, unknown> = {}): TaskStore & EventEmitter {
+function createStore(task: Task, settings: Record<string, unknown> = {}, mergeQueuedTaskIds: string[] = []): TaskStore & EventEmitter {
   const emitter = new EventEmitter() as TaskStore & EventEmitter;
   (emitter as any).getSettings = vi.fn().mockResolvedValue({
     autoMerge: true,
@@ -30,6 +30,16 @@ function createStore(task: Task, settings: Record<string, unknown> = {}): TaskSt
     task.column = column as any;
     task.updatedAt = new Date(Date.now()).toISOString();
   });
+  (emitter as any).peekMergeQueue = vi.fn(() => mergeQueuedTaskIds.map((taskId) => ({
+    taskId,
+    enqueuedAt: new Date().toISOString(),
+    priority: "normal",
+    leasedBy: null,
+    leasedAt: null,
+    leaseExpiresAt: null,
+    attemptCount: 0,
+    lastError: null,
+  })));
   (emitter as any).recordRunAuditEvent = vi.fn().mockResolvedValue(undefined);
   return emitter;
 }
@@ -80,6 +90,49 @@ describe("reliability interactions: in-review-stalled detector", () => {
     manager.stop();
   });
 
+  it("does not surface merge-stalled badges for tasks already queued in the merge lane", async () => {
+    const task = baseTask({
+      id: "FN-6088",
+      status: "merging",
+      error: null,
+      updatedAt: "2026-01-01T00:00:00.000Z",
+      columnMovedAt: "2026-01-01T00:00:00.000Z",
+    });
+    const store = createStore(task, { inReviewStalledThresholdMs: 3_600_000 }, ["FN-6088"]);
+    const manager = new SelfHealingManager(store, { rootDir: "/tmp/repo", getExecutingTaskIds: () => new Set() });
+
+    vi.setSystemTime(new Date("2026-01-01T06:00:00.000Z"));
+
+    expect(await manager.surfaceInReviewStalls()).toBe(0);
+    expect(await manager.surfaceInReviewStalled()).toBe(0);
+    expect(await manager.recoverGhostReviewTasks()).toBe(0);
+    expect(task.column).toBe("in-review");
+    expect(task.log?.some((entry) => entry.action.includes("stall"))).toBe(false);
+
+    manager.stop();
+  });
+
+  it("does not kick queued completed review tasks back to todo as ghost reviews", async () => {
+    const task = baseTask({
+      id: "FN-6086",
+      status: null,
+      error: null,
+      steps: [],
+      inReviewStall: undefined,
+      worktree: "/tmp/wt",
+    });
+    const store = createStore(task, { inReviewStalledThresholdMs: 3_600_000, taskStuckTimeoutMs: 12 * 3_600_000 }, ["FN-6086"]);
+    const manager = new SelfHealingManager(store, { rootDir: "/tmp/repo", getExecutingTaskIds: () => new Set() });
+
+    vi.setSystemTime(new Date("2026-01-01T13:00:00.000Z"));
+
+    expect(await manager.recoverGhostReviewTasks()).toBe(0);
+    expect(await manager.surfaceInReviewStalled()).toBe(0);
+    expect(task.column).toBe("in-review");
+
+    manager.stop();
+  });
+
   it("paused in-review tasks are owned by stale-paused-review detector", async () => {
     const task = baseTask({ paused: true, pausedReason: "manual-hold", status: "failed", error: null });
     const store = createStore(task);

packages/engine/src/self-healing.ts

@@ -663,6 +663,26 @@ export class SelfHealingManager {
     return this.options.getActiveMergeTaskId?.() ?? null;
   }
 
+  private isMergeLaneOwned(taskId: string): boolean {
+    if (this.options.getActiveMergeTaskId?.() === taskId) return true;
+
+    try {
+      return this.store.peekMergeQueue().some((entry) => entry.taskId === taskId);
+    } catch (err: unknown) {
+      const errorMessage = err instanceof Error ? err.message : String(err);
+      log.warn(`Unable to inspect merge queue ownership for ${taskId}: ${errorMessage}`);
+      return false;
+    }
+  }
+
+  private isFalseCompletionHandoffExhaustionWhileMergeOwned(task: Task): boolean {
+    return task.column === "in-review"
+      && task.status === "failed"
+      && typeof task.error === "string"
+      && task.error.includes("Completion handoff limbo recovery exhausted")
+      && this.isMergeLaneOwned(task.id);
+  }
+
   private emitTaskMerged(task: Task | undefined | null, overrides: Partial<MergeResult> = {}): void {
     if (!task) return;
     this.store.emit("task:merged", {
@@ -5391,6 +5411,7 @@ export class SelfHealingManager {
           engineActivationGraceMs: settings.engineActivationGraceMs,
         });
         if (!signal) continue;
+        if (this.isMergeLaneOwned(task.id)) continue;
 
         if (Date.parse(task.updatedAt) >= cycleStartMs) {
           continue;
@@ -5520,6 +5541,7 @@ export class SelfHealingManager {
         if (!allowsAutoMergeProcessing(task, settings)) continue;
         if (task.paused === true) continue;
         if (task.id === activeMergeTaskId || executingTaskIds.has(task.id)) continue;
+        if (this.isMergeLaneOwned(task.id)) continue;
 
         const signal = getInReviewStalledSignal(task, {
           now: cycleStartMs,
@@ -5690,6 +5712,7 @@ export class SelfHealingManager {
         allowsAutoMergeProcessing(task, settings) &&
         !task.paused &&
         !executingIds.has(task.id) &&
+        !this.isMergeLaneOwned(task.id) &&
         !(task.status && GHOST_REVIEW_PRESERVED_STATUSES.has(task.status)) &&
         // Confirmed merges belong in `done` (handled by `recoverMergedReviewTasks`).
         task.mergeDetails?.mergeConfirmed !== true &&
@@ -6970,8 +6993,21 @@ export class SelfHealingManager {
     for (const task of tasks) {
       if (task.column !== "in-review" || task.paused) continue;
       if (!allowsAutoMergeProcessing(task, settings)) continue;
+      if (this.isFalseCompletionHandoffExhaustionWhileMergeOwned(task)) {
+        await this.store.updateTask(task.id, {
+          status: null,
+          error: null,
+          completionHandoffLimboRecoveryCount: 0,
+        });
+        await this.store.logEntry(
+          task.id,
+          "Auto-recovered: cleared false completion-handoff exhaustion while task is already owned by merge queue",
+        );
+        continue;
+      }
       if (task.status != null || task.mergeDetails != null || task.review != null || task.reviewState != null) continue;
       if (this.options.isTaskActive?.(task.id)) continue;
+      if (this.isMergeLaneOwned(task.id)) continue;
       if (getTaskMergeBlocker(task) !== undefined) continue;
 
       const doneMarker = [...(task.log ?? [])].reverse().find((entry) => entry.action === "Task marked done by agent");