fix(agent): polish interrupt-resume flow for merge readiness

backend/tests/unit/v1/agent/test_resume_idempotency.py

@@ -17,6 +17,7 @@ class FakeAsyncSession:
     def __init__(self) -> None:
         self.added: list[object] = []
         self._sessions: dict[UUID, AgentChatSession] = {}
+        self.last_fetch_with_lock = False
 
     def add(self, obj: object) -> None:
         self.added.append(obj)
@@ -35,8 +36,17 @@ class FakeAsyncSession:
     async def refresh(self, obj: object) -> None:
         pass
 
-    async def execute(self, stmt: object) -> None:
-        pass
+    async def execute(self, stmt: object):
+        self.last_fetch_with_lock = "FOR UPDATE" in str(stmt)
+
+        class _Result:
+            def __init__(self, session_obj: AgentChatSession | None) -> None:
+                self._session_obj = session_obj
+
+            def scalar_one_or_none(self) -> AgentChatSession | None:
+                return self._session_obj
+
+        return _Result(next(iter(self._sessions.values()), None))
 
     async def scalar(self, stmt: object) -> AgentChatSession | None:
         for session in self._sessions.values():
@@ -69,7 +79,10 @@ def service(fake_db: FakeAsyncSession) -> AgentChatService:
 class TestResumeIdempotency:
     @pytest.mark.asyncio
     async def test_resume_is_idempotent(
-        self, service: AgentChatService, session: AgentChatSession
+        self,
+        service: AgentChatService,
+        session: AgentChatSession,
+        fake_db: FakeAsyncSession,
     ):
         expires_at = datetime.now(timezone.utc) + timedelta(hours=1)
         await service.set_pending_tool_call(
@@ -78,6 +91,8 @@ class TestResumeIdempotency:
             tool_name="srv.transfer_funds",
             tool_args={"to": "u2", "amount": 100},
             expires_at=expires_at,
+            thread_id="t1",
+            run_id="r1",
         )
 
         first = await service.apply_resume_decision(
@@ -93,6 +108,7 @@ class TestResumeIdempotency:
 
         assert first.applied is True
         assert second.applied is False
+        assert fake_db.last_fetch_with_lock is True
 
     @pytest.mark.asyncio
     async def test_resume_updates_status_to_approved(
@@ -105,6 +121,8 @@ class TestResumeIdempotency:
             tool_name="srv.delete_file",
             tool_args={"file_id": "f1"},
             expires_at=expires_at,
+            thread_id="t1",
+            run_id="r1",
         )
 
         result = await service.apply_resume_decision(
@@ -129,6 +147,8 @@ class TestResumeIdempotency:
             tool_name="srv.transfer_funds",
             tool_args={"to": "u2", "amount": 100},
             expires_at=expires_at,
+            thread_id="t1",
+            run_id="r1",
         )
 
         result = await service.apply_resume_decision(
@@ -140,3 +160,28 @@ class TestResumeIdempotency:
         assert result.applied is True
         snapshot = await service.get_state_snapshot(session.id)
         assert snapshot["pending_tool_call"]["status"] == "REJECTED"
+
+    @pytest.mark.asyncio
+    async def test_resume_expired_pending_marks_expired_and_not_applied(
+        self, service: AgentChatService, session: AgentChatSession
+    ):
+        expires_at = datetime.now(timezone.utc) - timedelta(seconds=1)
+        await service.set_pending_tool_call(
+            session_id=session.id,
+            interrupt_id="int-expired",
+            tool_name="srv.transfer_funds",
+            tool_args={"to": "u2", "amount": 100},
+            expires_at=expires_at,
+            thread_id="t1",
+            run_id="r1",
+        )
+
+        result = await service.apply_resume_decision(
+            session_id=session.id,
+            interrupt_id="int-expired",
+            decision={"decision": "approved"},
+        )
+
+        assert result.applied is False
+        snapshot = await service.get_state_snapshot(session.id)
+        assert snapshot["pending_tool_call"]["status"] == "EXPIRED"