fix(shell): exit gracefully with crash report when CWD is removed during session

[n-WN]

Related Issue

Resolves #1621 — Infinite error cascade when working directory is removed (e.g. external drive unplugged).

Description

Root Cause

_render_bottom_toolbar() calls KaosPath.cwd() → os.getcwd() on every render cycle to display the current working directory in the status bar. When the CWD no longer exists (external drive unplugged, directory deleted, filesystem unmounted), os.getcwd() raises OSError: [Errno 2].

This triggers a cascade:

render cycle → KaosPath.cwd() → OSError
  → prompt_toolkit _handle_exception() → "Press ENTER to continue..."
    → _do_wait_for_enter() → new PromptSession → render cycle → KaosPath.cwd() → OSError
      → _handle_exception() → "Press ENTER to continue..."
        → ... (infinite loop)

prompt_toolkit's event loop catches unhandled exceptions and shows a "Press ENTER to continue..." prompt — but that prompt itself triggers a redraw, which calls os.getcwd() again, creating an infinite error cascade that floods the terminal. The user must force-kill the process.

Note: other CWD-dependent calls in the same file (_get_git_branch(), _get_git_status()) are already wrapped with contextlib.suppress(Exception), but the toolbar CWD display is not.

Fix

prompt.py — CwdLostError + detection:

• Add CwdLostError(OSError) exception class
• Catch OSError at the KaosPath.cwd() call site in _render_bottom_toolbar
• Call app.exit(exception=CwdLostError()) to cleanly terminate the prompt_toolkit application
• Return an empty FormattedText so the current render frame completes without error

__init__.py — graceful exit with crash report:

• Catch CwdLostError in _route_prompt_events, emit a cwd_lost event
• Handle the event in the main shell loop: print a rich-formatted crash panel with session ID and working directory, then exit cleanly

Before / After

Before (v1.27.0)	After (this branch)
Infinite error cascade, must force-kill	Graceful crash panel, clean exit

Key files changed

• src/kimi_cli/ui/shell/prompt.py — CwdLostError class, catch OSError in _render_bottom_toolbar, exit prompt_toolkit app
• src/kimi_cli/ui/shell/__init__.py — _print_cwd_lost_crash() method, CwdLostError handling in event router and main loop
• tests/ui_and_conv/test_shell_prompt_router.py — unit test for CwdLostError event routing

Checklist

• I have read the CONTRIBUTING document.
• I have linked the related issue, if any.
• I have added tests that prove my fix is effective or that my feature works.
• I have run make gen-changelog to update the changelog.
• I have run make gen-docs to update the user documentation.

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Handle unresolved home dir in CWD fallback

If KaosPath.cwd() fails and this recovery branch runs, Path.home() can raise RuntimeError when ~ cannot be resolved (for example, stripped-down container users without a valid HOME/passwd entry). Because only OSError is handled here, that exception escapes and the toolbar redraw still crashes, reintroducing the repeated prompt_toolkit error loop this change is meant to avoid. Make the fallback path resolution exception-safe before calling os.chdir.

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[n-WN]

已不存在此问题