fix(filter): guard starts and stops in cardano

[wolf31o2]

Summary by cubic

Guarded the Cardano filter start/stop lifecycle to prevent race conditions and panics during shutdown. This makes concurrent event processing safer.

• Bug Fixes
  • Added a sync.WaitGroup to track the processEvents goroutine (Add in Start, Done in processEvents).
  • Stop now closes doneChan, waits for the goroutine to exit, then closes input/output channels.
  • Updated tests to start before stopping and removed assumptions about channels being nil after stop.

^{Written for commit 03308c5. Summary will update on new commits.}

Summary by CodeRabbit

• Bug Fixes

  • Improved graceful shutdown of the Cardano filter component for more reliable termination.

• Tests

  • Updated Cardano shutdown tests to validate the complete Start/Stop lifecycle.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Changes introduce synchronization using a sync.WaitGroup to the Cardano struct. The Start method increments the wait group before launching the worker goroutine, and the processEvents method defers a Done() call to signal completion. The Stop method now calls Wait() before closing channels. The corresponding test was restructured to call Start before Stop, with removal of post-stop channel-nil assertions.

🚥 Pre-merge checks | ✅ 2

✅ 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 accurately reflects the main change: adding synchronization guards (via sync.WaitGroup) to properly coordinate Cardano component starts and stops, ensuring graceful shutdown.

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✨ Finishing touches

• 📝 Generate docstrings

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📜 Recent review details

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between b27d127 and 03308c5.

📒 Files selected for processing (2)

• filter/cardano/cardano.go
• filter/cardano/cardano_test.go

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

• GitHub Check: cubic · AI code reviewer
• GitHub Check: Analyze (go)

🔇 Additional comments (5)

filter/cardano/cardano_test.go (1)

157-164: LGTM! Test now properly exercises the Start/Stop lifecycle.

The test correctly calls Start() before Stop(), which properly exercises the shutdown synchronization added in the implementation. Removing the post-stop channel-nil checks is correct since the channels are closed, not set to nil.

filter/cardano/cardano.go (4)

33-33: Excellent addition of WaitGroup for proper shutdown synchronization.

The sync.WaitGroup field correctly enables coordination between the worker goroutine and shutdown logic, preventing the race condition where channels could be closed while the goroutine is still sending events.

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55-56: Correct WaitGroup usage in Start().

Calling wg.Add(1) before launching the goroutine follows the proper pattern and ensures the counter is incremented before the worker starts.

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62-62: Proper deferred Done() ensures cleanup on all exit paths.

The deferred wg.Done() correctly signals completion when the goroutine exits, regardless of whether it returns via the doneChan signal (line 66) or closed inputChan (line 70).

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293-294: Critical fix: Wait for goroutine exit before closing channels.

The wg.Wait() call ensures the processEvents() goroutine has fully exited before closing the channels. This prevents a race condition where the goroutine could panic attempting to send on a closed outputChan (line 77). The shutdown sequence is now safe:

1. Close doneChan to signal shutdown
2. Block on wg.Wait() until the worker exits
3. Close channels safely

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[cubic-dev-ai]

No issues found across 2 files