{"record":{"id":"e20980199f3c7a87","repo":"gofiber/fiber","slug":"failed-to-dump-request-w","errorCode":null,"errorMessage":"failed to dump request: %w","messagePattern":"failed to dump request: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"app.go","lineNumber":1424,"sourceCode":"\t}\n\n\t// Ensure Host header is present in the dump (required by fasthttp)\n\tif req.Host == \"\" {\n\t\tif req.URL != nil && req.URL.Host != \"\" {\n\t\t\treq.Host = req.URL.Host\n\t\t} else {\n\t\t\treq.Host = \"localhost\"\n\t\t}\n\t}\n\n\t// Clear RequestURI so DumpRequest writes origin-form request line with\n\t// Host header instead of absolute-form URI without Host header.\n\treq.RequestURI = \"\"\n\n\t// Dump raw http request\n\tdump, err := httputil.DumpRequest(req, true)\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"failed to dump request: %w\", err)\n\t}\n\n\t// Create test connection\n\tconn := new(testConn)\n\n\t// Write raw http request\n\tif _, err = conn.r.Write(dump); err != nil {\n\t\treturn nil, fmt.Errorf(\"failed to write: %w\", err)\n\t}\n\t// prepare the server for the start\n\tapp.startupProcess()\n\n\t// Serve conn to server\n\tchannel := make(chan error, 1)\n\tgo func() {\n\t\tvar returned bool\n\t\tdefer func() {\n\t\t\tif !returned {","sourceCodeStart":1406,"sourceCodeEnd":1442,"githubUrl":"https://github.com/gofiber/fiber/blob/a105acad6c1e4576a77f01e02973f67e962bb58d/app.go#L1406-L1442","documentation":"In app.Test() the request is serialized via httputil.DumpRequest(req, true) before being written to an in-memory testConn. If DumpRequest fails (invalid header bytes, body serialization issues), the wrapped error is returned. This is a TestClient failure, not a runtime server failure.","triggerScenarios":"Calling app.Test(req) with an *http.Request that contains headers or a body httputil.DumpRequest cannot serialize (e.g., invalid header characters, control bytes, malformed Content-Length).","commonSituations":"Hand-building *http.Request with invalid header values; reusing requests across goroutines; bugs in test helpers that set headers from raw user input.","solutions":["Build requests with http.NewRequest or fiber.NewRequest so headers are validated at construction.","Inspect the wrapped error to find the offending header/body byte.","Avoid setting header values containing CR/LF or control characters."],"exampleFix":"// before\nreq := &http.Request{Method: \"GET\", Header: http.Header{\"X-Bad\": {\"a\\nb\"}}}\nresp, _ := app.Test(req)\n\n// after\nreq := httptest.NewRequest(\"GET\", \"/\", nil)\nreq.Header.Set(\"X-Good\", \"a-b\")\nresp, _ := app.Test(req)","handlingStrategy":"validation","validationCode":"// Build with http.NewRequest so headers are validated at construction\nreq, err := http.NewRequest(method, url, body)\nif err != nil { return err }","typeGuard":"func validHeaders(h http.Header) bool {\n    for k, vs := range h {\n        if !httpguts.ValidHeaderFieldName(k) { return false }\n        for _, v := range vs { if !httpguts.ValidHeaderFieldValue(v) { return false } }\n    }\n    return true\n}","tryCatchPattern":"resp, err := app.Test(req)\nif err != nil {\n    return fmt.Errorf(\"test harness failed to dump request: %w\", err)\n}","preventionTips":["Prefer http.NewRequest / httptest.NewRequest over hand-built requests.","Never inject raw user input into header values.","Keep app.Test() for in-process tests; use a real server for unusual payloads."],"tags":["testing","http","test-client","headers"],"backgroundTag":null,"analyzedSha":"a105acad6c1e4576a77f01e02973f67e962bb58d","analyzedAt":"2026-08-11T17:33:26.942Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}