Cleanup and --list-sessions race each other

[jpmartins98]

What happened?

Startup launches cleanupExpiredSessions() as a background task. It is not awaited. A few lines later, the CLI handles --list-sessions and starts reading the same session directory. Cleanup can delete files while listing is scanning them. A file can exist during readdir, then disappear before readFile. The list shown to the user can therefore depend on timing rather than a stable snapshot.

packages/cli/src/gemini.tsx:667

  cleanupExpiredSessions(config, settings.merged).catch((e) => {
    debugLogger.error('Failed to cleanup expired sessions:', e);
  });

packages/cli/src/gemini.tsx:681

  if (config.getListSessions()) {
    // ...
    await listSessions(config);
  }

What did you expect to happen?

Listing sessions should produce a stable result. If cleanup must run on startup, finish it before listing starts. If startup delay is a concern, skip cleanup for --list-sessions or make listing use a stable snapshot. The user should not see sessions randomly vanish because two internal tasks touched the same files at once.

Client information

Client Information

Run gemini to enter the interactive CLI, then run the /about command.

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│ Tier                                                                                           Gemini Code Assist in Google One AI Pro                                                                                                                                          │
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Login information

Signed in with Google

Anything else we need to know?

No response

[gemini-cli]

Effort Analysis:
In gemini.tsx, cleanupExpiredSessions() is launched as a non-awaited background task immediately followed by listSessions(). This creates a race where cleanup can delete files that listing has already detected, leading to intermittent 404/file-not-found errors during startup. As a 'race condition' affecting 'Asynchronous Flow', this is categorized as medium effort due to the difficulty of consistent reproduction and the need for proper async coordination at the entry point.

[i-anubhav-anand]

Opened #27906 with a fix + test. The unawaited cleanupExpiredSessions() races listSessions() over the same directory, so the listed result depends on timing (a file can exist during readdir then vanish before readFile). The PR skips the background cleanup when the run only reads/mutates the session list (--list-sessions / --delete-session); cleanup still runs on normal startups. Could a maintainer triage this for review?