fix(pty): suppress benign EPIPE errors on session shutdown

[Abdel-E]

Handle stdio EPIPE/EIO/ECONNRESET in lifecycle fallback and attach PTY pipe suppression on all platforms so closing agent sessions does not throw uncaught main-process errors.

Summary

Closing agent sessions can tear down PTYs/stdio pipes while Node is still reading from them, which can surface as an uncaught main-process exception (Error: read EPIPE, Pipe.onStreamRead). This PR:

• Ignores benign shutdown errors (EPIPE/EIO/ECONNRESET) on lifecycle fallback child_process stdio streams
• Attaches PTY pipe error suppression on all platforms (not only Windows)
• Adds/updates tests to cover these shutdown paths

Fixes

Snapshot

N/A — runtime stability fix (no UI change)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Chore (refactoring code, technical debt, workflow improvements)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (does not change functionality, e.g. code style improvements, linting)
• This change requires a documentation update

Mandatory Tasks

• I have self-reviewed the code

Checklist

• I have read the contributing guide
• I have commented my code, particularly in hard-to-understand areas
• I have checked if my PR needs changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

Summary by CodeRabbit

• Bug Fixes
  • Pseudoterminal error suppression now works consistently across all platforms, extending functionality that was previously limited to Windows
  • Stream error detection has been improved to identify and properly handle benign shutdown-related errors without propagating them
  • Process lifecycle error handling has been refined to prevent unnecessary error notifications and improve overall system stability

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: c1b38bf6-559f-4070-98d4-16de1b9b0930

📥 Commits

Reviewing files that changed from the base of the PR and between c797ed5 and a48ac34.

📒 Files selected for processing (2)

• src/main/services/ptyManager.ts
• src/test/main/ptyManager.test.ts

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📝 Walkthrough

Walkthrough

Updates PTY and child process stream error handling to suppress benign shutdown-related errors (EPIPE, EIO, ECONNRESET) across all platforms. Extends error suppression from Windows-only to universal platform coverage and adds error propagation logic for non-benign errors with proper UTF-8 buffering.

Changes

Cohort / File(s)	Summary
PTY Manager Implementation src/main/services/ptyManager.ts	Removed platform guard from suppressPtyPipeErrors() to apply error suppression universally; added isBenignStreamShutdownError() helper to classify EPIPE/EIO/ECONNRESET errors; extended LifecycleSpawnFallbackChild type to support error listeners on stdout/stderr; implemented error handlers that suppress benign errors but propagate others with buffered output flushing.
PTY Manager Tests src/test/main/ptyManager.test.ts	Updated PTY error suppression test to verify handler attachment on all platforms (not just Windows); added new test case validating benign EPIPE error suppression in lifecycle spawn fallback handlers without triggering the error callback.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related issues

• [bug]: Uncaught read EPIPE in main process when closing an agent session (Codex, etc.) #1683: Directly addressed—fixes uncaught read EPIPE main-process crashes when closing agent sessions by suppressing benign stream shutdown errors on PTYs and child processes.

Possibly related PRs

• fix: suppress EPIPE during PTY shutdown on Windows #1565: Related code modification—both PRs enhance error suppression in ptyManager.ts for PTY pipe errors (EPIPE/EIO), though this PR extends coverage to child process streams and cross-platform support.

Poem

🐰 Pipes were breaking, streams did cry,
EPIPE errors made processes die,
Now benign shutdowns gently rest,
While true errors still raise their test,
Hopping forth with buffered grace! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(pty): suppress benign EPIPE errors on session shutdown' directly and accurately summarizes the main change: suppressing EPIPE errors that occur during PTY session shutdown across platforms.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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