fix(engine): split stuck requeue fallback handling

packages/engine/src/__tests__/reliability-interactions/non-progress-churn.test.ts

@@ -4,6 +4,7 @@ import "../executor-test-helpers.js";
 import type { Task, TaskStore } from "@fusion/core";
 import { TaskExecutor } from "../../executor.js";
 import { SelfHealingManager } from "../../self-healing.js";
+import { isRunnableQueuedOverlapCandidate } from "../../scheduler.js";
 import { StuckTaskDetector } from "../../stuck-task-detector.js";
 
 type MockTaskStore = TaskStore & EventEmitter & {
@@ -219,6 +220,7 @@ describe("reliability interactions: non-progress churn", () => {
     expect(task.steps).toEqual([{ name: "Implement", status: "in-progress" }]);
     expect(task.log?.some((entry) => entry.action.includes("incomplete task exhausted stuck kill budget"))).toBe(true);
     expect(store.handoffToReview).not.toHaveBeenCalled();
+    expect(isRunnableQueuedOverlapCandidate(task, [task])).toBe(true);
 
     manager.stop();
   });

packages/engine/src/__tests__/self-healing.test.ts

@@ -494,6 +494,40 @@ describe("SelfHealingManager", () => {
       );
     });
 
+    it("logs post-move requeue patch failures without executor fallback", async () => {
+      (store.getTask as ReturnType<typeof vi.fn>).mockResolvedValue({
+        id: "FN-001",
+        column: "in-progress",
+        stuckKillCount: 6,
+        steps: [
+          { name: "Preflight", status: "done" },
+          { name: "Delivery", status: "in-progress" },
+        ],
+      } as unknown as Task);
+      (store.updateTask as ReturnType<typeof vi.fn>)
+        .mockResolvedValueOnce({} as Task)
+        .mockRejectedValueOnce(new Error("write conflict"));
+
+      manager.start();
+
+      const result = await manager.checkStuckBudget("FN-001", "loop");
+
+      expect(result).toBe(false);
+      expect(store.moveTask).toHaveBeenCalledWith("FN-001", "todo", {
+        preserveProgress: true,
+        preserveStatus: true,
+      });
+      expect(store.logEntry).toHaveBeenCalledWith(
+        "FN-001",
+        "STUCK_LOOP_EXHAUSTED: incomplete task moved to todo with progress preserved, but post-move requeue patch failed (write conflict); scheduler retry may wait for the next state repair pass.",
+      );
+      expect(store.logEntry).toHaveBeenCalledWith(
+        "FN-001",
+        "STUCK_LOOP_EXHAUSTED: incomplete task exhausted stuck kill budget (7/6), last reason=loop. Re-queued in todo with progress preserved; scheduler may retry without manual unpause.",
+      );
+      expect(store.handoffToReview).not.toHaveBeenCalled();
+    });
+
     it("terminalizes no-progress churn without incrementing stuck kill budget", async () => {
       (store.getTask as ReturnType<typeof vi.fn>).mockResolvedValue({
         id: "FN-001",

packages/engine/src/self-healing.ts

@@ -1079,14 +1079,6 @@ export class SelfHealingManager {
               preserveProgress: true,
               preserveStatus: true,
             });
-            const requeueUpdate = {
-              stuckKillCount: newCount,
-              paused: false,
-              userPaused: false,
-              pausedReason: null,
-              status: "queued",
-            } satisfies Parameters<typeof this.store.updateTask>[1] & { userPaused: boolean };
-            await this.store.updateTask(taskId, requeueUpdate);
           } catch (moveErr: unknown) {
             const moveErrMessage = moveErr instanceof Error ? moveErr.message : String(moveErr);
             log.warn(`${taskId} moveTask(todo) failed (${moveErrMessage}) after incomplete STUCK_LOOP_EXHAUSTED terminalization — falling back to executor stuck-kill requeue`);
@@ -1096,6 +1088,24 @@ export class SelfHealingManager {
             );
             return true;
           }
+
+          const requeueUpdate = {
+            stuckKillCount: newCount,
+            paused: false,
+            userPaused: false,
+            pausedReason: null,
+            status: "queued",
+          } satisfies Parameters<typeof this.store.updateTask>[1] & { userPaused: boolean };
+          try {
+            await this.store.updateTask(taskId, requeueUpdate);
+          } catch (patchErr: unknown) {
+            const patchErrMessage = patchErr instanceof Error ? patchErr.message : String(patchErr);
+            log.warn(`${taskId} post-move requeue patch failed after incomplete STUCK_LOOP_EXHAUSTED terminalization: ${patchErrMessage}`);
+            await this.store.logEntry(
+              taskId,
+              `STUCK_LOOP_EXHAUSTED: incomplete task moved to todo with progress preserved, but post-move requeue patch failed (${patchErrMessage}); scheduler retry may wait for the next state repair pass.`,
+            );
+          }
           await this.store.logEntry(
             taskId,
             `STUCK_LOOP_EXHAUSTED: incomplete task exhausted stuck kill budget (${newCount}/${maxKills}), last reason=${reason}. Re-queued in todo with progress preserved; scheduler may retry without manual unpause.`,