What causes "Unable to create package.json: ${e}" in hcengineering/platform?

Check permissions and writability of the package install folder (and free disk space) before running.

Unable to create package.json: ${e}

Error message

Unable to create package.json: ${e}

What it means

_createPackageJson writes a minimal package.json (name 'ci-rush', dependencies omitted, MIT license) into packageInstallFolder so npm can install the requested package. If fs.writeFileSync fails (or JSON serialization throws), the error is wrapped as 'Unable to create package.json: <cause>'.

Source

Thrown at foundations/net/common/scripts/install-run.js:626

    }
}
function _createPackageJson(packageInstallFolder, name, version) {
    try {
        const packageJsonContents = {
            name: 'ci-rush',
            version: '0.0.0',
            dependencies: {
                [name]: version
            },
            description: "DON'T WARN",
            repository: "DON'T WARN",
            license: 'MIT'
        };
        const packageJsonPath = path__WEBPACK_IMPORTED_MODULE_3__.join(packageInstallFolder, PACKAGE_JSON_FILENAME);
        fs__WEBPACK_IMPORTED_MODULE_1__.writeFileSync(packageJsonPath, JSON.stringify(packageJsonContents, undefined, 2));
    }
    catch (e) {
        throw new Error(`Unable to create package.json: ${e}`);
    }
}
/**
 * Run "npm install" in the package install folder.
 */
function _installPackage(logger, packageInstallFolder, name, version, command) {
    try {
        logger.info(`Installing ${name}...`);
        const npmPath = getNpmPath();
        const platformNpmPath = _getPlatformPath(npmPath);
        const result = child_process__WEBPACK_IMPORTED_MODULE_0__.spawnSync(platformNpmPath, [command], {
            stdio: 'inherit',
            cwd: packageInstallFolder,
            env: process.env,
            shell: _isWindows()
        });
        if (result.status !== 0) {
            throw new Error(`"npm ${command}" encountered an error`);

View on GitHub (pinned to 63e28dc964)

Solutions

Check permissions and writability of the package install folder (and free disk space) before running.
Delete the rush temp/install folder and re-run so it is recreated cleanly.
Avoid concurrent install-run invocations sharing the same install folder.
If permissions were changed by running as root previously, fix ownership (chown) of the temp directory.

Defensive patterns

Strategy: validation

Validate before calling

// Verify the install folder is writable before running the script
const fs = require('fs');
fs.mkdirSync(installFolder, { recursive: true });
fs.accessSync(installFolder, fs.constants.W_OK);
const probe = require('path').join(installFolder, '.write-probe');
fs.writeFileSync(probe, 'ok');
fs.unlinkSync(probe);

Try / catch

try {
  runInstallRun();
} catch (e) {
  if (/Unable to create package\.json/.test(e.message)) {
    console.error(`Install folder not writable or full: ${e.message}`);
    // clean and re-create the folder once
    require('fs').rmSync(packageInstallFolder, { recursive: true, force: true });
    runInstallRun();
  } else throw e;
}

Prevention

Ensure the rush temp/install folder is writable by the user running the script.
Monitor free disk space in CI before dependency install steps.
Fix ownership after any sudo-elevated runs in the same directory.
Avoid concurrent runs that could delete the folder mid-write.

When it happens

Trigger: installAndRun → _createPackageJson, when the install folder is not writable (EACCES/EPERM), does not exist (ENOENT after a failed clean step), is on a full disk (ENOSPC), or the path is invalid/locked on Windows.

Common situations: Read-only CI workspace or cache directory; disk quota exceeded; the folder was deleted between the clean and write steps by a concurrent process; permissions broken by a previous sudo-invoked run.

Related errors

AI-assisted analysis of hcengineering/platform@63e28dc964 (2026-08-29). Data as JSON: /api/errors/939212c7a876e39a. Report an issue: GitHub.