fix: harden CLI interrupt handling for shell mode and chat compression

[chrisjcthomas]

This PR improves how Gemini CLI handles user interruptions via Escape and Ctrl+C to ensure a more consistent and reliable user experience.

Improvements

• Interrupt Handling (Shell Mode) (Bug: Pressing Escape in '!' shell mode cancels ongoing agent request instead of exiting shell mode #20615): Fixed a bug where pressing Escape while in shell mode (typing a ! command) would accidentally cancel ongoing background agent requests. Now, Escape correctly exits shell mode without affecting the agent.
• Interrupt Handling (Compression): Threaded the abortSignal from the current turn into the ChatCompressionService. This ensures that when a user cancels a request (e.g., via Ctrl+C), any in-flight API calls for chat summarization/compression are also immediately aborted.

Verification

• Manually verified that pressing Escape in shell mode no longer cancels background thoughts.
• Verified that abortSignal is correctly passed from AppContainer through GeminiClient and LocalExecutor into the compression service.

Closes #20615

[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 significantly enhances the robustness of the Gemini CLI's interrupt handling mechanisms. It addresses critical scenarios where user input, such as pressing "Escape" or "Ctrl+C", did not behave as expected, leading to unintended cancellations of background processes or API calls. The changes ensure a more predictable and reliable user experience by correctly propagating cancellation signals and refining input interpretations.

Highlights

• Shell Mode Interrupts: Resolved an issue where pressing "Escape" in shell mode (when typing a "!" command) would inadvertently cancel ongoing background agent requests. "Escape" now correctly exits shell mode without affecting agent operations.
• Chat Compression Interrupts: Integrated "abortSignal" into the "ChatCompressionService" to ensure that user cancellations (e.g., via "Ctrl+C") also immediately abort any in-flight API calls related to chat summarization or compression.

Changelog

• docs/cli/sandbox.md
  • Updated a bullet point to clarify that adding to a custom Dockerfile for missing commands requires running from source code and is not available via npm installation.
• docs/reference/configuration.md
  • Added a note explaining that building custom sandboxes from a Dockerfile is only supported when running the CLI from source, and provides guidance for npm installations.
• packages/cli/src/ui/commands/compressCommand.ts
  • Modified the "tryCompressChat" call to pass "context.ui.abortSignal", enabling cancellation of compression requests.
• packages/cli/src/ui/hooks/useGeminiStream.ts
  • Adjusted the "useKeypress" hook condition to include "!shellModeActive" when checking for the "escape" key, preventing unintended request cancellations while in shell mode.
• packages/core/src/agents/local-executor.ts
  • Updated the "tryCompressChat" method signature to accept an optional "abortSignal".
  • Passed the "abortSignal" to the "tryCompressChat" call within the "execute" method.
  • Modified the internal call to "ChatCompressionService" to include the "abortSignal".
• packages/core/src/core/client.ts
  • Updated the "tryCompressChat" method signature to accept an optional "abortSignal".
  • Passed the "abortSignal" to the "tryCompressChat" call within the "generateContentStream" method.
  • Modified the internal call to "ChatCompressionService" to include the "abortSignal".
• packages/core/src/services/chatCompressionService.ts
  • Removed the fallback "new AbortController().signal" for "abortSignal" in "callModel" and "verifySummary" methods, ensuring the provided "abortSignal" is used directly.

Activity

• Manually verified that pressing "Escape" in shell mode no longer cancels background thoughts.
• Verified that "abortSignal" is correctly passed from "AppContainer" through "GeminiClient" and "LocalExecutor" into the compression service.

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[gemini-code-assist]

Code Review

This pull request hardens interrupt handling in the CLI, which is a great improvement for user experience. The changes correctly propagate the abortSignal for chat compression and fix an issue with the Escape key in shell mode. I've identified a potential issue where the removal of a fallback for the abortSignal could make the chat compression service less robust, potentially hindering cancellability. My review includes suggestions to address this by ensuring AbortSignals are consistently propagated, aligning with best practices for asynchronous operations.

_{Note: Security Review did not run due to the size of the PR.}

[chrisjcthomas]

Thanks for catching this! Both instances have been fixed in commit b133082 — the ?? new AbortController().signal fallback has been restored on both generateContent calls to ensure a valid AbortSignal is always provided, even when compress() is called without one.

[chrisjcthomas]

@jkcinouye I cleaned up the stale Gemini review threads on this PR and updated the description to match the current scope. If you have a chance, I’d appreciate a review.

[chrisjcthomas]

@g-samroberts adding you here as well since you had context on #21679. I cleaned up the stale Gemini review threads and updated the description to match the current scope; if you have a chance, I’d appreciate a review.

[spencer426]

Thank you for your interest in contributing to the project! We are closing this PR as the issue was already fixed.