fix(watchdogs): atomically claim self reviews

Prevent concurrent watchdog evaluations from duplicating comments, trigger
bookkeeping, activity, and wake requests for the same stopped fingerprint.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/task-watchdogs-scheduler.test.ts

@@ -371,6 +371,34 @@ describeEmbeddedPostgres("task watchdog scheduler", () => {
     expect(commentsAfter).toHaveLength(1);
   });
 
+  it("self mode atomically claims a stopped fingerprint across concurrent reconciliations", async () => {
+    const companyId = await seedCompany();
+    const agentId = await seedAgent(companyId);
+    const sourceId = await seedIssue(companyId, {
+      identifier: "WDOG-SELF-RACE",
+      status: "done",
+      assigneeAgentId: agentId,
+    });
+    await seedWatchdog(companyId, sourceId, agentId, {
+      mode: "self",
+      instructions: "Verify the report exists and passes lint.",
+    });
+    const { service, wakes } = createService();
+
+    const results = await Promise.all([
+      service.reconcileTaskWatchdogs({ companyId }),
+      service.reconcileTaskWatchdogs({ companyId }),
+    ]);
+
+    expect(results.reduce((total, result) => total + result.triggered, 0)).toBe(1);
+    expect(results.reduce((total, result) => total + result.alreadyReviewed, 0)).toBe(1);
+    expect(wakes).toHaveLength(1);
+    const comments = await db.select().from(issueComments).where(eq(issueComments.issueId, sourceId));
+    expect(comments).toHaveLength(1);
+    const [watchdog] = await db.select().from(issueWatchdogs).where(eq(issueWatchdogs.issueId, sourceId));
+    expect(watchdog?.triggerCount).toBe(1);
+  });
+
   it("does not trigger while a non-watchdog descendant has live work", async () => {
     const companyId = await seedCompany();
     const sourceId = await seedIssue(companyId, { identifier: "WDOG-2", status: "in_progress" });

server/src/services/task-watchdogs.ts

@@ -1527,6 +1527,31 @@ export function taskWatchdogService(db: Db, deps: TaskWatchdogServiceDeps = {})
     runId: string | null;
   }) {
     const { watchdog, sourceIssue, classification } = input;
+    const now = new Date();
+    const claimed = await db
+      .update(issueWatchdogs)
+      .set({
+        lastObservedFingerprint: classification.stopFingerprint,
+        lastObservedStopSnapshot: classification.stopSnapshot,
+        lastReviewedFingerprint: classification.stopFingerprint,
+        lastReviewedStopSnapshot: classification.stopSnapshot,
+        lastTriggeredAt: now,
+        triggerCount: sql`${issueWatchdogs.triggerCount} + 1`,
+        updatedAt: now,
+      })
+      .where(and(
+        eq(issueWatchdogs.id, watchdog.id),
+        sql`${issueWatchdogs.lastReviewedFingerprint} is distinct from ${classification.stopFingerprint}`,
+      ))
+      .returning({ id: issueWatchdogs.id });
+    if (claimed.length === 0) {
+      return {
+        ...classification,
+        state: "already_reviewed" as const,
+        reason: "The current stopped subtree fingerprint was already claimed for self review.",
+      };
+    }
+
     await issuesSvc.addComment(
       sourceIssue.id,
       buildSelfReviewComment({
@@ -1547,20 +1572,6 @@ export function taskWatchdogService(db: Db, deps: TaskWatchdogServiceDeps = {})
       },
     );
 
-    const now = new Date();
-    await db
-      .update(issueWatchdogs)
-      .set({
-        lastObservedFingerprint: classification.stopFingerprint,
-        lastObservedStopSnapshot: classification.stopSnapshot,
-        lastReviewedFingerprint: classification.stopFingerprint,
-        lastReviewedStopSnapshot: classification.stopSnapshot,
-        lastTriggeredAt: now,
-        triggerCount: sql`${issueWatchdogs.triggerCount} + 1`,
-        updatedAt: now,
-      })
-      .where(eq(issueWatchdogs.id, watchdog.id));
-
     await logActivity(db, {
       companyId: sourceIssue.companyId,
       actorType: "system",