fix(cli): propagate exit signal callbacks

[he-yufeng]

Summary

• make _ExitCli inherit from KeyboardInterrupt so asyncio callback frames re-raise it instead of routing it to the loop exception handler
• keep _ExitCli outside Exception, preserving the previous fix for broad except Exception handlers
• add a regression test for the callback-frame race described in _ExitCli still swallowed by asyncio Handle._run after PR #5519 (callback-frame race) #5856

Fixes #5856.

To verify

• uv run pytest tests/test_drain_timeout.py -q
• uv run ruff check livekit-agents\livekit\agents\cli\cli.py tests\test_drain_timeout.py
• uv run ruff format --check livekit-agents\livekit\agents\cli\cli.py tests\test_drain_timeout.py
• uv run python -m py_compile livekit-agents\livekit\agents\cli\cli.py tests\test_drain_timeout.py
• git diff --check

[devin-ai-integration]

Devin Review found 1 potential issue.

View 3 additional findings in Devin Review.

[devin-ai-integration]

🔴 _ExitCli swallowed in console text mode due to except KeyboardInterrupt now catching it

Changing _ExitCli's base class from BaseException to KeyboardInterrupt causes _ExitCli to be caught by the except KeyboardInterrupt: break handler in _text_mode (cli.py:1181). Previously, _ExitCli(BaseException) would bypass that handler and propagate up to the except _ExitCli: pass in _run_console (cli.py:1563), triggering a clean shutdown. Now, _ExitCli(KeyboardInterrupt) is caught at line 1181, _text_mode returns normally, and the while True loop at cli.py:1553 simply restarts text mode. The first SIGTERM/SIGINT in console text mode is silently swallowed instead of initiating shutdown. Moreover, exit_triggered is already True after the first signal, so subsequent signals call console_worker.shutdown() without raising, leaving the main thread stuck in the prompt() → readkey() blocking call.

Prompt for agents

The root cause is that _text_mode (cli.py:1168) catches KeyboardInterrupt at line 1181, and _ExitCli is now a subclass of KeyboardInterrupt, so _ExitCli raised from the signal handler gets caught there instead of propagating to the outer except _ExitCli handler in _run_console (line 1563).

To fix this, the except KeyboardInterrupt handler in _text_mode needs to distinguish between a native KeyboardInterrupt (raised by readkey() on Ctrl+C, see readchar.py:201) and _ExitCli. The simplest fix is to re-raise _ExitCli:

  In _text_mode (around line 1181), change:
    except KeyboardInterrupt:
        break
  to:
    except _ExitCli:
        raise
    except KeyboardInterrupt:
        break

This ensures _ExitCli propagates out to _run_console while still letting the native KeyboardInterrupt from readkey() break the text input loop.

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[longcw]

@he-yufeng thanks for the pr! I think this is a real issue, maybe re-raise the _ExitCli in _text_mode first.

        try:
            text = prompt(
                Text.from_markup("  [bold]User input[/bold]: "),
                console=c.console,
                key_read_cb=_key_read,
                placeholder="Type to talk to your agent",
            )
        except _ExitCli:
            raise
        except KeyboardInterrupt:
            break