vercel/turborepo · error · ConvertError

package_json-parse_error

package_json-parse_error

Error message

failed to parse "package.json" at ${workspaceRoot}

What it means

The same getPackageJson() helper: when readJsonSync fails because JSON.parse cannot parse the file, the error carries code EJSONPARSE and is converted to ConvertError `failed to parse "package.json" at <root>` (type package_json-parse_error). The file exists but is not valid JSON.

Solutions

1. Validate the file: node -e "JSON.parse(require('fs').readFileSync('package.json','utf8'))" to get the exact offset
2. Remove comments, trailing commas, and BOM; quote all keys
3. Restore a known-good version with git checkout -- package.json if the breakage came from a merge or bad write

Example fix

// before (invalid: comment + trailing comma)
{
  // workspace config
  "name": "monorepo",
  "private": true,
}
// after
{
  "name": "monorepo",
  "private": true
}

import { readFileSync } from "node:fs";
const raw = readFileSync(manifestPath, "utf8").replace(/^\uFEFF/, "");
try {
  JSON.parse(raw);
} catch (e) {
  throw new Error(`package.json is not valid JSON: ${(e as Error).message}`);
}

function isConvertError(e: unknown): e is { type: string } {
  return typeof e === "object" && e !== null && "type" in e;
}

try {
  await readWorkspace(args);
} catch (e) {
  if (isConvertError(e) && e.type === "package_json-parse_error") {
    // JSON.parse the file yourself to get the line/column, fix the syntax, retry
  } else {
    throw e;
  }
}

When it happens

Trigger: package.json containing JSON5 syntax (comments, trailing commas, unquoted keys), a UTF-8 BOM, single-quoted strings, or a file truncated mid-write; unresolved git merge conflict markers left in the manifest.

Common situations: Hand-editing package.json and pasting commented JSON; a CI job or codegen writing the file non-atomically; a partially resolved merge; an editor auto-inserting trailing commas.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• package_json-missing
• pnpm-workspace_parse_error
• Unable to read package.json
• Found both turbo.json and turbo.jsonc in the same directory
• Found both turbo.json and turbo.jsonc in the same directory

AI-assisted analysis of vercel/turborepo@f9245100cf (2026-08-17). Data as JSON: /api/errors/26ffa0bfcdbfac52. Report an issue: GitHub.

Appendix: source

Thrown at packages/turbo-workspaces/src/utils.ts:69

]);

function getPackageJson({
  workspaceRoot
}: {
  workspaceRoot: string;
}): PackageJson {
  const packageJsonPath = path.join(workspaceRoot, "package.json");
  try {
    return readJsonSync(packageJsonPath, "utf8") as PackageJson;
  } catch (err) {
    if (err && typeof err === "object" && "code" in err) {
      if (err.code === "ENOENT") {
        throw new ConvertError(`no "package.json" found at ${workspaceRoot}`, {
          type: "package_json-missing"
        });
      }
      if (err.code === "EJSONPARSE") {
        throw new ConvertError(
          `failed to parse "package.json" at ${workspaceRoot}`,
          {
            type: "package_json-parse_error"
          }
        );
      }
    }
    throw new Error(
      `unexpected error reading "package.json" at ${workspaceRoot}`
    );
  }
}

function getWorkspacePackageManager({
  workspaceRoot
}: {
  workspaceRoot: string;
}): PackageManager | undefined {

View on GitHub (pinned to f9245100cf)