fix: coordinate concurrent first downloads of the same cache key - #3
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resolve()'s check-then-download wasn't coordinated across threads: N threads racing the first resolve() of a key (e.g. a thread pool calling chembl_bridge() concurrently right after enable_cache()) each saw it missing and each downloaded it in full. Reproduced directly: 16 threads calling chembl_bridge() concurrently on an empty cache logged 16 separate "caching ..." downloads of the same file instead of one. Fixed with a per-key lock: the first thread to reach a key downloads it, the rest wait and then reuse the file it wrote. Verified the same repro now logs exactly one download. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01L4ztUhMgoMFRicB8uiYx76
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Summary
resolve()'s check-then-download wasn't coordinated across threads: N threads racing the firstresolve()of a key (e.g. a thread pool callingchembl_bridge()right afterenable_cache()) each saw it missing and each downloaded it in full. Reproduced directly: 16 threads callingchembl_bridge()concurrently on an empty cache logged 16 separate downloads of the same file instead of one.cache.py: the first thread to reach a key downloads it, the rest wait and reuse the file it wrote.Test plan
pytest -q— 41 passedmypy src/scigantic_bindingdb(strict) — clean🤖 Generated with Claude Code
https://claude.ai/code/session_01L4ztUhMgoMFRicB8uiYx76