{"record":{"id":"cf4a0e9b7d19e979","repo":"wavetermdev/waveterm","slug":"json-syntax-error-at-line-d-col-d-probably-an","errorCode":null,"errorMessage":"json syntax error at line %d, col %d: probably an extra trailing comma: %v","messagePattern":"json syntax error at line (.+?), col (.+?): probably an extra trailing comma: (.+?)","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/wconfig/settingsconfig.go","lineNumber":538,"sourceCode":"\tvar cerrs []ConfigError\n\tif readErr != nil && !os.IsNotExist(readErr) {\n\t\tcerrs = append(cerrs, ConfigError{File: fileName, Err: readErr.Error()})\n\t}\n\tif len(barr) == 0 {\n\t\treturn nil, cerrs\n\t}\n\tvar rtn waveobj.MetaMapType\n\terr := json.Unmarshal(barr, &rtn)\n\tif err != nil {\n\t\tif syntaxErr, ok := err.(*json.SyntaxError); ok {\n\t\t\toffset := syntaxErr.Offset\n\t\t\tif offset > 0 {\n\t\t\t\toffset = offset - 1\n\t\t\t}\n\t\t\tlineNum, colNum := utilfn.GetLineColFromOffset(barr, int(offset))\n\t\t\tisTrailingComma := isTrailingCommaError(barr, int(offset))\n\t\t\tif isTrailingComma {\n\t\t\t\terr = fmt.Errorf(\"json syntax error at line %d, col %d: probably an extra trailing comma: %v\", lineNum, colNum, syntaxErr)\n\t\t\t} else {\n\t\t\t\terr = fmt.Errorf(\"json syntax error at line %d, col %d: %v\", lineNum, colNum, syntaxErr)\n\t\t\t}\n\t\t}\n\t\tcerrs = append(cerrs, ConfigError{File: fileName, Err: err.Error()})\n\t}\n\n\t// Resolve environment variable replacements\n\tif rtn != nil {\n\t\tresolveEnvReplacements(rtn)\n\t}\n\n\treturn rtn, cerrs\n}\n\nfunc readConfigFileFS(fsys fs.FS, logPrefix string, fileName string) (waveobj.MetaMapType, []ConfigError) {\n\tbarr, readErr := fs.ReadFile(fsys, fileName)\n\tif readErr != nil {","sourceCodeStart":520,"sourceCodeEnd":556,"githubUrl":"https://github.com/wavetermdev/waveterm/blob/a4447c1563b2df285ab89e76c82f91e1a1a49c1e/pkg/wconfig/settingsconfig.go#L520-L556","documentation":"This is the trailing-comma variant of the JSON syntax error produced while parsing Wave configuration files. When a json.SyntaxError occurs and isTrailingCommaError detects the offending offset points at a trailing comma, the error is wrapped with a 'probably an extra trailing comma' hint plus line/column. It is collected into ConfigError entries and returned by the Generate* meta-constant functions.","triggerScenarios":"Parsing a settings/config JSON file that contains a comma after the last element of an object or array (e.g. {\"a\": 1,}), via ReadWaveHomeConfigFile/GenerateSettingsMetaConsts and related generators.","commonSituations":"Hand-editing ~/.waveterm/config/settings.json and leaving a trailing comma after the final key; merging config snippets generated by copy-paste; JSON5 habits applied to strict JSON files.","solutions":["Open the file at the reported line/column and delete the trailing comma before the closing brace/bracket","Run the file through a strict JSON linter or `python -m json.tool <file>` to find all syntax issues","If the file should tolerate relaxed syntax, ensure it uses the Wave config format that supports comments/relaxations expected by your Wave version"],"exampleFix":"// before (settings.json)\n{\n  \"app:dismissarchitecturewarning\": true,\n}\n// after\n{\n  \"app:dismissarchitecturewarning\": true\n}","handlingStrategy":"validation","validationCode":"var raw map[string]any\nif err := json.Unmarshal(data, &raw); err != nil {\n    var se *json.SyntaxError\n    if errors.As(err, &se) {\n        line, col := getLineCol(data, int(se.Offset))\n        return fmt.Errorf(\"config JSON invalid at %d:%d — check for trailing comma\", line, col)\n    }\n    return err\n}","typeGuard":null,"tryCatchPattern":"err := wconfig.SetBaseConfigValue(toMerge)\nif err != nil && strings.Contains(err.Error(), \"trailing comma\") {\n    // surface file+line to user, offer to auto-strip trailing commas\n}","preventionTips":["Run strict JSON validation after every manual config edit","Disable editor features that allow trailing commas in strict JSON files","Lint config files in CI before shipping presets"],"tags":["json","syntax-error","trailing-comma","config","go"],"backgroundTag":"json-syntax-error","analyzedSha":"a4447c1563b2df285ab89e76c82f91e1a1a49c1e","analyzedAt":"2026-09-01T15:26:23.972Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T15:18:49.778Z"}