{"id":"e3f0f0b14ce5811b","repo":"gofiber/fiber","slug":"limiter-failed-to-marshal-key-q-w","errorCode":null,"errorMessage":"limiter: failed to marshal key %q: %w","messagePattern":"limiter: failed to marshal key %q: %w","errorType":"http","errorClass":null,"httpStatus":null,"severity":"error","filePath":"middleware/limiter/manager.go","lineNumber":102,"sourceCode":"\tif value == nil {\n\t\treturn m.acquire(), nil\n\t}\n\n\tit, ok := value.(*item)\n\tif !ok {\n\t\treturn nil, fmt.Errorf(\"limiter: unexpected entry type %T for key %q\", value, m.logKey(key))\n\t}\n\n\treturn it, nil\n}\n\n// set data to storage or memory\nfunc (m *manager) set(ctx context.Context, key string, it *item, exp time.Duration) error {\n\tif m.storage != nil {\n\t\traw, err := it.MarshalMsg(nil)\n\t\tif err != nil {\n\t\t\tm.release(it)\n\t\t\treturn fmt.Errorf(\"limiter: failed to marshal key %q: %w\", m.logKey(key), err)\n\t\t}\n\t\tif err := m.storage.SetWithContext(ctx, key, raw, exp); err != nil {\n\t\t\tm.release(it)\n\t\t\treturn fmt.Errorf(\"limiter: failed to store key %q: %w\", m.logKey(key), err)\n\t\t}\n\t\tm.release(it)\n\t\treturn nil\n\t}\n\n\tm.memory.Set(key, it, exp)\n\treturn nil\n}\n\nfunc (m *manager) logKey(key string) string {\n\tif m.shouldRedactKeys {\n\t\treturn redactedKey\n\t}\n\treturn key","sourceCodeStart":84,"sourceCodeEnd":120,"githubUrl":"https://github.com/gofiber/fiber/blob/9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c/middleware/limiter/manager.go#L84-L120","documentation":"Returned by manager.set when the *item cannot be serialized via msgp (MarshalMsg) before writing to external storage. This is the encoding counterpart of the unmarshal error.","triggerScenarios":"it.MarshalMsg(nil) fails at manager.go:99. msgp marshaling of the simple item struct (three numeric fields) is essentially infallible in practice; hitting this indicates a broken/generated msgp implementation, memory corruption, or an extremely unusual runtime fault.","commonSituations":"Running generated manager_msgp.go that is out of sync with the item struct (forgot to run go generate); msgp codegen version mismatch; memory corruption.","solutions":["Regenerate msgp code: run `make generate` (or `go generate ./middleware/limiter/...`).","Confirm the installed msgp version matches the one referenced in AGENTS.md/Makefile.","Rebuild the binary from a clean cache to rule out stale generated code."],"exampleFix":null,"handlingStrategy":"validation","validationCode":"// Guard codegen sync at build time: ensure generated msgp is current.\n// In CI, run: go generate ./middleware/limiter/... && git diff --exit-code","typeGuard":null,"tryCatchPattern":"// A marshal failure is effectively unrecoverable at runtime; log and\n// return 500.\nif strings.Contains(err.Error(), \"failed to marshal key\") {\n    log.Error().Err(err).Msg(\"limiter msgp marshal failed\")\n    return c.Status(500).SendString(\"internal error\")\n}","preventionTips":["Always run `make generate` after changing the item struct.","Keep the msgp toolchain version pinned across all developers/CI.","Commit generated manager_msgp.go and verify it builds cleanly."],"tags":["limiter","storage","msgp","serialization","codegen"],"analyzedSha":"9a4c7e57fe0b080a04235d28a4b0d2b4b353d58c","analyzedAt":"2026-08-04T21:44:03.395Z","schemaVersion":2}