{"record":{"id":"a48bd1cbcdf7d26d","repo":"golang/go","slug":"error-processing-profile-header-w","errorCode":null,"errorMessage":"error processing profile header: %w","messagePattern":"error processing profile header: %w","errorType":"error_code","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/cmd/compile/internal/pgoir/irgraph.go","lineNumber":132,"sourceCode":"\t*pgo.Profile\n\n\t// WeightedCG represents the IRGraph built from profile, which we will\n\t// update as part of inlining.\n\tWeightedCG *IRGraph\n}\n\n// New generates a profile-graph from the profile or pre-processed profile.\nfunc New(profileFile string) (*Profile, error) {\n\tf, err := os.Open(profileFile)\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"error opening profile: %w\", err)\n\t}\n\tdefer f.Close()\n\tr := bufio.NewReader(f)\n\n\tisSerialized, err := pgo.IsSerialized(r)\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"error processing profile header: %w\", err)\n\t}\n\n\tvar base *pgo.Profile\n\tif isSerialized {\n\t\tbase, err = pgo.FromSerialized(r)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"error processing serialized PGO profile: %w\", err)\n\t\t}\n\t} else {\n\t\tbase, err = pgo.FromPProf(r)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"error processing pprof PGO profile: %w\", err)\n\t\t}\n\t}\n\n\tif base.TotalWeight == 0 {\n\t\treturn nil, nil // accept but ignore profile with no samples.\n\t}","sourceCodeStart":114,"sourceCodeEnd":150,"githubUrl":"https://github.com/golang/go/blob/b6b368adc57c96c3151d224d172029f233ead2c3/src/cmd/compile/internal/pgoir/irgraph.go#L114-L150","documentation":"After opening the PGO profile file, the compiler calls pgo.IsSerialized to detect whether the profile is in Go's serialized format or standard pprof format by reading its header bytes. This error wraps any failure from that detection step, indicating the file is not a recognizable PGO profile.","triggerScenarios":"Passing a corrupt, truncated, or non-profile file as the PGO profile. Passing a plain text file, JSON, or a file with an unrecognized magic number. A profile file that was partially overwritten.","commonSituations":"Using a stale or truncated profile file. Pointing -pgo to the wrong file (e.g., a coverage profile instead of a CPU profile). File corruption during git operations or transfer between machines.","solutions":["Regenerate the profile file from scratch with go test -cpuprofile=default.pgo","Validate the file is a real pprof profile: go tool pprof default.pgo","Ensure the profiling process completed without interruption or timeout","Verify the file size is reasonable (a valid profile should be at least several KB)"],"exampleFix":null,"handlingStrategy":"validation","validationCode":"// Quick sanity check on a PGO profile file\nfunc checkPGOProfile(path string) error {\n    f, err := os.Open(path)\n    if err != nil {\n        return err\n    }\n    defer f.Close()\n    header := make([]byte, 16)\n    n, _ := f.Read(header)\n    if n < 4 {\n        return fmt.Errorf(\"file too small to be a valid profile\")\n    }\n    // pprof profiles start with \\x00\\x00\\x00 or a specific gzip header\n    // Go serialized profiles have their own magic\n    if header[0] != 0x1f && header[1] != 0x8b && header[0] != 0x00 {\n        return fmt.Errorf(\"unrecognized profile format — regenerate with go test -cpuprofile\")\n    }\n    return nil\n}","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Regenerate profiles if you see header errors — do not attempt to repair them","Validate profiles with go tool pprof before using them for PGO builds","Keep profile generation and build steps in the same CI pipeline to avoid stale files","Do not manually edit or truncate profile files"],"tags":["go-compiler","go-pgo","data-parsing","file-validation"],"analyzedSha":"b6b368adc57c96c3151d224d172029f233ead2c3","analyzedAt":"2026-08-12T00:22:02.250Z","schemaVersion":2},"datasetVersion":"2026-08-12T06:17:24.410Z"}