[client] Fix nil pointer panic in ICE agent during sleep/wake cycles

[pappz]

Add defensive nil checks in ThreadSafeAgent.Close() to prevent panic when agent field is nil. This can occur during Windows suspend/resume when network interfaces are disrupted or the pion/ice library returns nil without error.

Also capture agent pointer in local variable before goroutine execution to prevent race conditions.

Fixes service crashes on laptop wake-up.

Describe your changes

Issue ticket number and link

Stack

Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)

By submitting this pull request, you confirm that you have read and agree to the terms of the Contributor License Agreement.

Documentation

Select exactly one:

• I added/updated documentation for this change
• Documentation is not needed for this change (explain why)

Docs PR URL (required if "docs added" is checked)

Paste the PR link from https://github.com/netbirdio/docs here:

https://github.com/netbirdio/docs/pull/__

Summary by CodeRabbit

• Bug Fixes
  • Enhanced ICE (Interactive Connectivity Establishment) agent initialization with better error detection and reporting
  • Improved ICE connection cleanup operations with enhanced error handling and logging

[coderabbitai]

📝 Walkthrough

Walkthrough

Added nil-safety checks to ICE agent initialization and closing operations. The NewAgent function now validates that the created agent is non-nil before proceeding, and the Close implementation guards against nil agents while preserving timeout-based cleanup behavior. Worker code also now checks before closing agents and logs errors.

Changes

Cohort / File(s)	Summary
ICE Agent Lifecycle Management client/internal/peer/ice/agent.go	Added nil-check after ice.NewAgent with formatted error return; modified Close to guard against nil agent, log warnings if nil, and preserve timeout-based cleanup via conditional goroutine execution.
Worker ICE Agent Cleanup client/internal/peer/worker_ice.go	Added nil-check before calling Close() on ICE agent and implemented per-call error logging for close failures.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related issues

• invalid memory address or nil pointer dereference on windows arm64 when sleeping laptop #5259 — Directly addresses the nil-pointer Close race condition by introducing nil-safety checks and guarded Close calls for ICE agents.

Possibly related PRs

• [client] Fix shutdown blocking on stuck ICE agent close #4780 — Both PRs modify the ThreadSafeAgent.Close behavior in client/internal/peer/ice/agent.go with timeout-based, non-blocking close logic and nil-safety improvements.

Suggested reviewers

• lixmal

Poem

🐰 A tale of pointers, once so wild,
Now checked for nil, both stern and mild,
With guards and timeouts standing tall,
Safe Close calls prevail for all! ✨

🚥 Pre-merge checks | ✅ 1 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	❓ Inconclusive	The description covers the core issue, provides context about the Windows suspend/resume scenario, and explains the fix. However, the 'Describe your changes' section remains empty, which is a required template section.	Fill in the 'Describe your changes' section with details about the defensive nil checks and local variable capture implementation to complete the template.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately and concisely summarizes the main change: adding nil pointer panic prevention in ICE agent during sleep/wake cycles, directly matching the changeset's defensive nil checks.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/ice-close-nil

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud