fix(core): thread abort signal through chat compression

[deadsmash07]

Summary

• Thread the parent abort signal from processTurn and executeTurn through tryCompressChat into the compression service
• Ctrl+C during chat compression now cancels the in-flight generateContent API calls immediately

Details

When the CLI triggers chat compression (summarization + verification LLM calls), pressing Ctrl+C didn't cancel the underlying API requests. Both generateContent calls in chatCompressionService.compress() were receiving a throwaway new AbortController().signal because tryCompressChat in both client.ts and local-executor.ts never forwarded the parent abort signal.

The fix adds an optional abortSignal parameter to both tryCompressChat methods and passes through the signals that are already available at the call sites (signal in processTurn, combinedSignal in executeTurn).

Related Issues

Fixes #20405

How to Validate

1. Start a long conversation that triggers chat compression
2. Press Ctrl+C while compression is running
3. Verify the API calls are cancelled immediately (no lingering requests)

Pre-Merge Checklist

• Updated relevant documentation and README (if needed) — N/A
• Added/updated tests (if needed) — Existing tests cover the compression flow; typecheck confirms signature compatibility
• Noted breaking changes (if any) — None (parameter is optional)
• 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 responsiveness of the application by implementing proper cancellation for long-running chat compression operations. By propagating existing abort signals through the chat compression logic, users can now interrupt ongoing LLM API calls immediately, preventing lingering requests and improving control during interactive sessions.

Highlights

• Abort Signal Propagation: The abortSignal is now threaded through tryCompressChat in both local-executor.ts and client.ts to the underlying chat compression service.
• Immediate Cancellation: Pressing Ctrl+C during chat compression will now immediately cancel in-flight generateContent API calls, improving user experience.

Changelog

• packages/core/src/agents/local-executor.ts
  • Modified tryCompressChat to accept an optional abortSignal parameter.
  • Passed the combinedSignal from executeTurn to tryCompressChat.
  • Forwarded the received abortSignal to the chat compression service.
• packages/core/src/core/client.ts
  • Modified tryCompressChat to accept an optional abortSignal parameter.
  • Passed the signal from processTurn to tryCompressChat.
  • Forwarded the received abortSignal to the chat compression service.

Activity

• The pull request addresses and fixes issue Bug: Ctrl+C doesn't cancel in-flight chat compression requests #20405.
• Existing tests are deemed sufficient to cover the compression flow, and type-checking confirmed signature compatibility.
• The changes introduce no breaking changes as the abortSignal parameter is optional.
• The changes have been validated on Linux using npm run.

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[gemini-code-assist]

Code Review

This pull request correctly threads the parent abort signal through the chat compression service. By adding an optional abortSignal parameter to tryCompressChat in local-executor.ts and client.ts, the change ensures that in-flight generateContent API calls during chat summarization can be properly cancelled. The implementation is straightforward and effectively resolves the issue of lingering API requests upon cancellation.

[deadsmash07]

Closing this — @Shiv-aurora's PR #20407 addresses the same issue and was opened first. No need for a duplicate.