{"record":{"id":"fec13d547b2453fe","repo":"vercel/next.js","slug":"failed-to-read-file-contents-of-filename","errorCode":null,"errorMessage":"Failed to read file contents of ${filename}.","messagePattern":"Failed to read file contents of (.+?)\\.","errorType":"exception","errorClass":"Error","httpStatus":null,"severity":"error","filePath":"packages/next/src/server/dev/get-source-map-from-file.ts","lineNumber":35,"sourceCode":"  if (!(match && match[1])) {\n    return null\n  }\n  return match[1].toString()\n}\n\nexport async function getSourceMapFromFile(\n  filename: string\n): Promise<RawSourceMap | undefined> {\n  filename = filename.startsWith('file://')\n    ? url.fileURLToPath(filename)\n    : filename\n\n  let fileContents: string\n\n  try {\n    fileContents = await fs.readFile(filename, 'utf-8')\n  } catch (error) {\n    throw new Error(`Failed to read file contents of ${filename}.`, {\n      cause: error,\n    })\n  }\n\n  const sourceUrl = getSourceMapUrl(fileContents)\n\n  if (!sourceUrl) {\n    return undefined\n  }\n\n  if (sourceUrl.startsWith('data:')) {\n    let buffer: dataUriToBuffer.MimeBuffer\n\n    try {\n      buffer = dataUriToBuffer(sourceUrl)\n    } catch (error) {\n      throw new Error(`Failed to parse source map URL for ${filename}.`, {\n        cause: error,","sourceCodeStart":17,"sourceCodeEnd":53,"githubUrl":"https://github.com/vercel/next.js/blob/0eb377541648e63402a47b38fee00a8d0ce8f8f1/packages/next/src/server/dev/get-source-map-from-file.ts#L17-L53","documentation":"I/O wrapper in getSourceMapFromFile: reading the file at filename (after file:// normalization) failed, and the original fs error is attached as cause. Missing files or permission problems on the compiled artifact are the usual triggers when the dev overlay tries to symbolicate a stack.","triggerScenarios":"Reading a file's contents to extract its source map fails.","commonSituations":"A deleted or unreadable file during dev error overlay source map resolution.","solutions":["Ensure the file exists and is readable; check permissions and that the path is correct."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"0eb377541648e63402a47b38fee00a8d0ce8f8f1","analyzedAt":"2026-08-19T02:10:13.922Z","contentChangedAt":"2026-08-19T02:10:13.922Z","schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}