🛡️ Sentinel: [CRITICAL] Fix Process pipe deadlocks

[NSEvent]

🚨 Severity: CRITICAL
💡 Vulnerability: Process deadlocks occurred when spawned processes produced more output than the OS pipe buffer capacity (~64KB). The app waited for process exit before reading the buffer, leading to indefinite blocking.
🎯 Impact: Denial of Service affecting process execution functions and child pid scraping, hanging the automation executor completely.
🔧 Fix: Reordered logic to ensure standard output/error pipes are read to the end of file before or concurrently (via waitUntilExit()) to drain the buffer and allow the child processes to terminate successfully.
✅ Verification: Tested static code for structure matching the fix in runProcess and childPIDs.

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PR created automatically by Jules for task 11218669982473773810 started by @NSEvent

Summary by CodeRabbit

• Bug Fixes
  • Improved reliability when running commands by ensuring process output is captured and handled correctly.
  • Prevented background discovery and connectivity checks from retaining unnecessary diagnostic output.
  • Improved stability for controller relay discovery and streaming-service integration checks.
  • Reduced the risk of stalled or incomplete subprocess operations during automation and device-related workflows.

[google-labs-jules]

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[coderabbitai]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 67b5da9d-a751-429d-b6ba-9481fe9d60a9

📥 Commits

Reviewing files that changed from the base of the PR and between b60553e and da25493.

📒 Files selected for processing (3)

• TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift
• XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift
• XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Walkthrough

Walkthrough

Subprocess handling now reads captured output before waiting for termination. Unused output streams are redirected to FileHandle.nullDevice. ShellCommandRunner disables its readability handler before clearing the process reference.

Changes

Process pipe handling

Layer / File(s)	Summary
Captured output ordering TriggerKit/Sources/TriggerKitRuntime/AutomationExecutor.swift, XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift	runProcess, childPIDs, and MediaMTX discovery read captured output before waiting for process termination. ShellCommandRunner disables its readability handler before clearing the process reference.
Unused stream redirection XboxControllerMapper/XboxControllerMapper/Services/Input/UniversalControlMouseRelay.swift, XboxControllerMapper/XboxControllerMapperTests/OBSWebSocketLiveIntegrationTests.swift	Tailscale discovery redirects stderr to FileHandle.nullDevice. The MediaMTX port probe redirects stdout and stderr to FileHandle.nullDevice.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to da254

No actionable merge-blocking risk remains based on the supplied current-head evidence; the PR is merge-ready after normal checks and review.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 6 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: fixing process pipe deadlocks.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch sentinel-fix-process-deadlock-11218669982473773810

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