{"record":{"id":"5ba0c0b52cc9bfff","repo":"apache/beam","slug":"malformed-input-for-decoding-s","errorCode":null,"errorMessage":"malformed input for decoding: %s","messagePattern":"malformed input for decoding: (.+?)","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"sdks/go/pkg/beam/core/util/hooks/hooks.go","lineNumber":302,"sourceCode":"func Encode(name string, opts []string) string {\n\tvar cfg bytes.Buffer\n\tw := csv.NewWriter(&cfg)\n\t// This should never happen since a bytes.Buffer doesn't fail to write.\n\tif err := w.Write(append([]string{name}, opts...)); err != nil {\n\t\tpanic(errors.Wrap(err, \"error encoding arguments\"))\n\t}\n\tw.Flush()\n\treturn cfg.String()\n}\n\n// Decode decodes a hook name and its arguments from a single string.\n// This is a convenience function for users of this package that are composing\n// hooks.\nfunc Decode(in string) (string, []string) {\n\tr := csv.NewReader(strings.NewReader(in))\n\ts, err := r.Read()\n\tif err != nil {\n\t\tpanic(errors.Wrapf(err, \"malformed input for decoding: %s\", in))\n\t}\n\treturn s[0], s[1:]\n}\n","sourceCodeStart":284,"sourceCodeEnd":306,"githubUrl":"https://github.com/apache/beam/blob/12126d8942aaf848030c478b4c6a28c6af861c66/sdks/go/pkg/beam/core/util/hooks/hooks.go#L284-L306","documentation":"hooks.Decode parses a hook-args string as CSV (\"name,arg1,arg2\") and panics with this wrapped error if csv.Reader cannot parse it — e.g. unbalanced quotes or bare quotation marks in the input. Unlike most of this package it panics rather than returning an error, so callers must ensure the string is valid CSV.","triggerScenarios":"Calling hooks.Decode(in) with a string containing malformed CSV: unmatched double quotes (e.g. `hook \"arg`), stray quote characters, or an empty/multiline string that csv.Read rejects (including io.EOF for empty input).","commonSituations":"Passing user-supplied hook arguments from job options or CLI flags that contain quotes; encoding a name with commas/quotes without proper CSV quoting; passing an empty string.","solutions":["Ensure the string is valid CSV: quote fields containing quotes/commas, e.g. name,\"arg with \"\"quotes\"\"\"","Sanitize or validate the input string before calling Decode; use csv.Reader yourself to get a returnable error instead of the panic","Trim whitespace and reject empty input before calling Decode","If encoding your own args, use hooks.Encode (or csv.Writer) so round-trips are valid"],"exampleFix":"// before\nname, args := hooks.Decode(userInput) // panics on `hook \"x`\n// after\nr := csv.NewReader(strings.NewReader(userInput))\nrec, err := r.Read()\nif err != nil || len(rec) == 0 {\n    return fmt.Errorf(\"invalid hook args %q: %w\", userInput, err)\n}\nname, args := rec[0], rec[1:]","handlingStrategy":"validation","validationCode":"func safeDecode(in string) (name string, args []string, err error) {\n    if strings.TrimSpace(in) == \"\" {\n        return \"\", nil, fmt.Errorf(\"empty hook spec\")\n    }\n    rec, err := csv.NewReader(strings.NewReader(in)).Read()\n    if err != nil || len(rec) == 0 {\n        return \"\", nil, fmt.Errorf(\"malformed hook spec %q: %v\", in, err)\n    }\n    return rec[0], rec[1:], nil\n}","typeGuard":null,"tryCatchPattern":"// Decode panics, so recover at the boundary if you must call it directly\nfunc decodeSafe(in string) (s string, args []string) {\n    defer func() { _ = recover() }()\n    return hooks.Decode(in)\n}","preventionTips":["Validate or produce hook-args strings with csv.Writer/Reader round-trips, never string concatenation","Reject empty and whitespace-only input before Decode","Escape double quotes in argument values per CSV rules (\"\" inside quoted fields)","Recover() around Decode when input comes from users, since it panics instead of returning an error"],"tags":["go","csv","panic","parsing","beam"],"backgroundTag":"invalid-argument-format","analyzedSha":"12126d8942aaf848030c478b4c6a28c6af861c66","analyzedAt":"2026-09-13T01:50:10.254Z","contentChangedAt":"2026-09-13T01:50:10.254Z","schemaVersion":2},"datasetVersion":"2026-09-14T16:17:12.679Z"}