Go Programming World
Sep 7, 2026 · Backend Development
Go GOPROXY Fallback Pitfall: Comma Separators Don't Handle 500 Errors—Use Pipe Instead
The article details a CI lint failure caused by a corrupted Go module from a GOPROXY mirror, revealing that comma-separated GOPROXY fallbacks only retry on 404/410 errors, while pipe-separated fallbacks retry on any error—a behavior confirmed by Go source code analysis.
CI debuggingGOPROXYGo modules
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