PR #25049: fix: resolve lifecycle memory leaks by cleaning up listeners and root closures

• Repository: google-gemini/gemini-cli
• Author: spencer426
• State: closed | merged: True
• Link: https://github.com/google-gemini/gemini-cli/pull/25049

Description (problem / solution / changelog)

Summary

This PR addresses multiple severe memory leaks that cause the CLI's memory usage to continually grow over long sessions, leading to terminal backbuffer retention and massive React Fiber tree bloat.

Details

1. TerminalBuffer & Render Teardown Leaks (cleanupFunctions): registerCleanup was being used in both interactiveCli.tsx and AppContainer.tsx to register instance.unmount() and background task termination logic. Because the application was missing a corresponding removeCleanup hook, these closures (and by extension the entire rootUiRef and internalOnBeforeRender functions from Ink) were retained indefinitely in the global array. A new removeCleanup utility function has been added to packages/cli/src/utils/cleanup.ts and called in the appropriate finally and React lifecycle cleanup stages to prevent this unbounded growth.
2. Fuzzy Finder Status Listener Leaks (statusChangeListeners): The statusChangeListeners in packages/core/src/tools/mcp-client.ts was implemented using a simple array. During rapid mounting/unmounting of the fuzzy finder dialog, failure to correctly find and slice listeners could cause duplicate retention. It has been converted to a Set<StatusChangeListener> which intrinsically enforces uniqueness and guards against these leaks.

Related Issues

Fixes #24924

How to Validate

Run preflgiht

Pre-Merge Checklist

<!-- Check all that apply before requesting review or merging. -->

• Updated relevant documentation and README (if needed)
• Added/updated tests (if needed)
• Noted breaking changes (if any)
• Validated on required platforms/methods:
  • MacOS
    • npm run
    • npx
    • Docker
    • Podman
    • Seatbelt
  • Windows
    • npm run
    • npx
    • Docker
  • Linux
    • npm run
    • npx
    • Docker

Changed files

• packages/cli/src/gemini.test.tsx (modified, +2/-1)
• packages/cli/src/gemini_cleanup.test.tsx (modified, +2/-0)
• packages/cli/src/interactiveCli.tsx (modified, +50/-8)
• packages/cli/src/ui/AppContainer.tsx (modified, +15/-3)
• packages/cli/src/utils/cleanup.ts (modified, +14/-0)
• packages/core/src/services/shellExecutionService.test.ts (modified, +7/-0)
• packages/core/src/services/shellExecutionService.ts (modified, +16/-1)
• packages/core/src/tools/mcp-client.ts (modified, +3/-6)