fix(webrtc): make session cleanup deadlock-safe

[21pages]

Notes

The issue was identified and fixed by AI, with NO TESTING PERFORMED.

Summary

This PR addresses potential deadlocks during WebRTC session cleanup.

• Release the data channel lock before awaiting close().
• Release the session cache lock before closing a duplicate peer.
• Remove cached sessions by PeerConnection identity instead of SDP fingerprint, preventing delayed callbacks from removing replacement sessions.
• Add regression tests for session-cache re-entry and identity-based cleanup.

Summary by CodeRabbit

• Bug Fixes
  • Improved WebRTC session handling to reliably reuse existing connections.
  • Prevented duplicate incoming streams from remaining active.
  • Ensured cached sessions are properly cleaned up when peer connections change state.
  • Reduced the risk of connection hangs during session reuse and closure.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 5146633b-54c6-471f-aae9-e351ab29b3b1

📥 Commits

Reviewing files that changed from the base of the PR and between c2d8a6d and 219f917.

📒 Files selected for processing (1)

• src/webrtc.rs

Included review availability: Your plan provides up to 2 included reviews per hour; 1 remains after this review.

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📝 Walkthrough

Walkthrough

The WebRTC session cache now uses dedicated helpers for duplicate-session reuse and peer-specific cleanup. Session creation and terminal peer states use these helpers. Tests cover close behavior without deadlock and selective cleanup.

Changes

WebRTC session cache

Layer / File(s)	Summary
Cache helpers and lifecycle integration src/webrtc.rs	Added helpers to reuse cached sessions and remove sessions that match a peer connection. Updated session creation and terminal peer-connection state cleanup to use the helpers.
Cache behavior tests src/webrtc.rs	Added test stream setup and tests for duplicate-session reuse without deadlock and cleanup that preserves sessions for unrelated peer connections.

Estimated code review effort: 3 (Moderate) | ~15–30 minutes

Merge Risk: ⚪ Minimal · up to 219f9

This localized cleanup change releases locks before peer closure and removes sessions by peer identity, reducing deadlock and stale-session deletion risk without changing public WebRTC access or deployment behavior. No actionable merge-blocking risk remains.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 55.56% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 9 functions across 1 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
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.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: making WebRTC session cleanup safe from deadlocks.

• Fix all pre-merge checks with AI

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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