fix: eliminate data race in maelstrom message parsing#918
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mattisonchao merged 1 commit intomainfrom Feb 27, 2026
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parseRequest() deserialized messages into singleton struct pointers stored in jsonMsgMapping/protoMsgMapping. Since message handlers run as goroutines (dispatcher.go:136), the next incoming message would overwrite the singleton while the previous goroutine was still reading from it, causing linearizability violations in the Maelstrom lin-kv test. Use reflect.New() to create a fresh instance from each prototype on every parse, so each goroutine gets its own isolated copy. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
parseRequest()deserialized messages into singleton struct pointers stored injsonMsgMapping/protoMsgMappingdispatcher.go:136), the next incoming message would overwrite the singleton while the previous goroutine was still reading from itFrom=1from a singleton that had been overwritten by a later message, when the actual register value was 3reflect.New()to create a fresh instance from each prototype on every parse, so each goroutine gets its own isolated copyTest plan