fix(core): whitelist TERM and COLORTERM in environment sanitization

[sripasg]

[original author - @deadsmash07 - from PR - 20514]

Summary

• Added TERM and COLORTERM to ALWAYS_ALLOWED_ENVIRONMENT_VARIABLES in the environment sanitization service
• These variables describe terminal capabilities and are safe to pass through — they're needed by terminal editors (vim, emacs) and interactive commands (top)
• The sandbox path already preserves these variables (see sandbox.ts), so this aligns the sanitization behavior

Details

Terminal-based editors fail to initialize ("Terminal type not defined") and interactive commands default to no-color mode because TERM and COLORTERM are stripped during environment sanitization. This change simply whitelists them so they pass through to spawned processes unchanged — no fallback values are introduced.

Related Issues

Fixes #20444

How to Validate

1. Set EDITOR=vim or EDITOR=emacs
2. Run Gemini CLI with environment variable redaction enabled
3. Trigger an editor operation (e.g., edit a plan)
4. Verify the editor starts correctly without "Terminal type not defined" errors
5. Run top via shell command and verify color support works

Pre-Merge Checklist

• Updated relevant documentation and README (if needed) — N/A
• Added/updated tests (if needed) — Two new tests covering normal and strict sanitization modes
• Noted breaking changes (if any) — None
• Validated on required platforms/methods:
  • Linux npm run

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the system's compatibility with terminal-based tools by ensuring essential environment variables are preserved during process execution. By allowing TERM and COLORTERM to pass through, it prevents functionality regressions for interactive applications and editors, leading to a more robust and predictable user experience when interacting with the CLI.

Highlights

• Environment Variable Whitelisting: The TERM and COLORTERM environment variables have been added to the ALWAYS_ALLOWED_ENVIRONMENT_VARIABLES list in the environment sanitization service.
• Terminal Compatibility Fix: This change resolves issues where terminal-based editors (like vim/emacs) and interactive commands (like top) failed to initialize or lost color support due to these variables being stripped.
• Behavior Alignment: The update aligns the environment sanitization behavior with the existing sandbox.ts logic, which already preserves these variables, ensuring consistent handling.

Changelog

• packages/core/src/services/environmentSanitization.test.ts
  • Added tests to confirm TERM and COLORTERM are allowed.
  • Added a test to ensure TERM and COLORTERM are preserved even in strict sanitization mode.
• packages/core/src/services/environmentSanitization.ts
  • Included TERM and COLORTERM in the ALWAYS_ALLOWED_ENVIRONMENT_VARIABLES set.

Activity

• No human activity has occurred on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request correctly whitelists the TERM and COLORTERM environment variables, which is crucial for compatibility with terminal-based tools. The changes are straightforward and include corresponding tests. The suggested improvement to one of the new tests to make it more robust has been retained as it aligns with general good testing practices and is not contradicted by any specific rules.

[github-actions]

Size Change: +146 B (0%)

Total Size: 26 MB

ℹ️ View Unchanged

Filename	Size	Change
./bundle/gemini.js	25.5 MB	+146 B (0%)
./bundle/node_modules/@google/gemini-cli-devtools/dist/client/main.js	221 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/_client-assets.js	227 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/index.js	11.5 kB	0 B
./bundle/node_modules/@google/gemini-cli-devtools/dist/src/types.js	132 B	0 B
./bundle/sandbox-macos-permissive-open.sb	890 B	0 B
./bundle/sandbox-macos-permissive-proxied.sb	1.31 kB	0 B
./bundle/sandbox-macos-restrictive-open.sb	3.36 kB	0 B
./bundle/sandbox-macos-restrictive-proxied.sb	3.56 kB	0 B
./bundle/sandbox-macos-strict-open.sb	4.82 kB	0 B
./bundle/sandbox-macos-strict-proxied.sb	5.02 kB	0 B

_{compressed-size-action}

[sripasg]

The original PR is by @deadsmash07 - here #20514

Thank you @deadsmash07 - but collaboration from maintainers a bit unwieldy with a PR request from a different cloned repo.

[sripasg]

This is not required. I opened it assuming it would be weird to push via cloned repo. It isn't 😊