fix(core,cli): improve terminal buffer memory management and format Windows diagnostic paths

[jesussamuel-byte]

Optimizes memory usage during PTY shell execution and headless terminal buffer serialization in ShellExecutionService and terminalSerializer, and improves Markdown formatting of Windows file paths in /bug and /bug-memory diagnostic messages.

Details

• Headless Terminal Buffer Sizing: Adjusts SCROLLBACK_LIMIT to 50,000 lines per headless terminal instance and enforces a MAX_CHILD_PROCESS_BUFFER_SIZE byte cap inside getFullBufferText using sliding window truncation (truncateMiddle).
• Color Serialization Optimization: Adds an optional includeColor parameter to serializeTerminalToObject to skip redundant RGB/palette hex string conversions when color output is disabled, and updates renderFn to clear color properties in-place without allocating duplicate arrays via .map().
• PTY Execution Lifecycle Cleanup:
  • Removes temporary onAbortDuringDrain listeners from AbortSignal upon normal process exit to avoid listener accumulation across repeated command executions.
  • Clears intermediate output and sniffChunks closure buffers and cancels pending renderTimeout timers during process finalization.
  • Updates ShellExecutionService.resetForTest() to properly tear down active PTY processes, child processes, and background log streams.
• Windows Path Markdown Formatting: Wraps file paths output by /bug and /bug-memory in inline code backticks so backslashes (e.g., C:\Users\ASUS\.gemini\...) are preserved accurately by Markdown renderers.
• Unit Test Coverage: Added unit tests covering includeColor = false serialization, AbortSignal listener cleanup on normal exit, resetForTest() resource teardown, and Windows path backtick formatting.

Related Issues

GH-27557

How to Validate

1. Run unit tests for ShellExecutionService, terminalSerializer, bugCommand, and bugMemoryCommand:

   npm test -w @google/gemini-cli-core -- src/services/shellExecutionService.test.ts src/utils/terminalSerializer.test.ts
   npm test -w @google/gemini-cli -- src/ui/commands/bugCommand.test.ts src/ui/commands/bugMemoryCommand.test.ts

2. Run full preflight checks (format, lint, and typecheck):

   npm run format && npm run lint:ci && npm run typecheck

Pre-Merge Checklist

• 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

[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 introduces critical memory management and stability improvements for terminal execution within the core and CLI packages. By optimizing buffer sizing, streamlining serialization processes, and ensuring rigorous cleanup of PTY and child process resources, the changes significantly reduce the risk of memory leaks and performance degradation during long-running shell operations. Additionally, it addresses minor UI formatting issues to improve the readability of diagnostic file paths on Windows.

Highlights

• Memory Management: Reduced the headless terminal scrollback limit to 50,000 lines and implemented a sliding window truncation for terminal buffers to prevent excessive V8 heap growth.
• Serialization Optimization: Added an optional includeColor parameter to terminal serialization to avoid unnecessary color processing and optimized color property clearing to avoid redundant array allocations.
• Resource Lifecycle Cleanup: Improved PTY lifecycle management by ensuring proper cleanup of AbortSignal listeners, clearing closure buffers, and adding a robust resetForTest method to tear down active processes and streams.
• Markdown Formatting: Wrapped Windows file paths in diagnostic messages with backticks to ensure backslashes are correctly rendered in Markdown.

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[github-actions]

📊 PR Size: size/L

• Lines changed: 359
• Additions: +306
• Deletions: -53
• Files changed: 8

[gemini-code-assist]

Code Review

This pull request addresses memory leaks and excessive V8 heap growth during shell execution. Key changes include reducing the scrollback limit, releasing intermediate closure buffers, properly cleaning up active PTYs and event listeners on exit, and updating serializeTerminalToObject to optionally omit foreground and background colors. Additionally, file paths in bug commands are now wrapped in backticks to prevent Markdown escaping on Windows. The review feedback points out a redundant loop in shellExecutionService.ts that manually clears fg and bg colors when showColor is disabled, as this is already handled internally by serializeTerminalToObject when passing the includeColor parameter. Removing this loop will avoid unnecessary O(N*M) traversals and improve rendering efficiency.

[jesussamuel-byte]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces memory optimizations, robust cleanup mechanisms, and path formatting fixes. It wraps Windows file paths in backticks within the bug and memory commands to prevent Markdown backslash escaping. In the core package, it reduces the terminal scrollback limit to prevent excessive V8 heap growth, optimizes terminal serialization by allowing color omission, ensures proper disposal of event listeners and active PTYs (including a thorough cleanup in resetForTest), and releases intermediate closure buffers to prevent heap retention. As there are no review comments, I have no additional feedback to provide.