The original title is "The Cache Was Working. And Still Causing Duplicate API Calls"

Short summary

CommitPulse's caching layer had a thundering herd bug where concurrent cache misses triggered multiple identical GitHub API calls while the first request was in-flight. The fix uses an in-flight Promise map to deduplicate pending requests—subsequent callers share the same pending Promise instead of spawning independent fetches. This pattern prevents rate-limit exhaustion under high concurrent load.

• •Concurrent cache misses caused duplicate API calls despite having a cache
• •Solution: track in-flight Promises separately and return existing pending request to concurrent callers
• •Prevents thundering herd problem that exhausts rate limits under traffic spikes

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