fix: cancel journal read before closing stream

src/github_agent_bridge/backend.py

@@ -296,6 +296,8 @@ async def _session_stream_events(db: str | Path, job_id: int, *, after_id: int |
 async def _journal_stream_events(unit: str, *, shutdown_event: asyncio.Event | None = None):
     try:
         stream = stream_journal_lines(unit)
+        line_task: asyncio.Task | None = None
+        shutdown_task: asyncio.Task | None = None
         try:
             while shutdown_event is None or not shutdown_event.is_set():
                 line_task = asyncio.create_task(anext(stream))
@@ -322,6 +324,11 @@ async def _journal_stream_events(unit: str, *, shutdown_event: asyncio.Event | N
                         return
                 yield _sse_event("journal_line", {"unit": unit, "line": line})
         finally:
+            pending_tasks = [task for task in (line_task, shutdown_task) if task is not None and not task.done()]
+            for task in pending_tasks:
+                task.cancel()
+            if pending_tasks:
+                await asyncio.gather(*pending_tasks, return_exceptions=True)
             await stream.aclose()
     except FileNotFoundError:
         yield _sse_event("journal_error", {"unit": unit, "error": "journalctl_not_found"})

tests/test_backend.py

@@ -958,6 +958,31 @@ async def stream_until_shutdown():
     asyncio.run(stream_until_shutdown())
 
 
+def test_dashboard_journal_stream_cancels_pending_read_when_client_disconnects(monkeypatch):
+    closed = False
+
+    async def fake_stream_journal_lines(unit):
+        nonlocal closed
+        try:
+            await asyncio.sleep(60)
+            yield "unreachable"
+        finally:
+            closed = True
+
+    async def disconnect_stream():
+        shutdown = asyncio.Event()
+        monkeypatch.setattr("github_agent_bridge.backend.stream_journal_lines", fake_stream_journal_lines)
+        stream = _journal_stream_events("github-agent-bridge-dashboard.service", shutdown_event=shutdown)
+        pending_chunk = asyncio.create_task(anext(stream))
+        await asyncio.sleep(0)
+        pending_chunk.cancel()
+        with pytest.raises(asyncio.CancelledError):
+            await pending_chunk
+        assert closed is True
+
+    asyncio.run(disconnect_stream())
+
+
 def test_dashboard_requires_auth_by_default(tmp_path):
     db = tmp_path / "bridge.sqlite3"
     JobQueue(db)