microsoft/monaco-editor · error · Error

Missing PRERELEASE_VERSION in process.env

Error message

Missing PRERELEASE_VERSION in process.env

What it means

Thrown by getNightlyEnv() when process.env.PRERELEASE_VERSION is falsy. getNightlyEnv is only called by the nightly release path, which uses PRERELEASE_VERSION to compute the prerelease tag (e.g. 0.x.x-dev.YYYYMMMM) appended to the base version. The guard ensures a nightly never ships without a prerelease suffix, which would collide with the stable version on npm. The check runs before any git clone or build step.

Source

Thrown at scripts/ci/env.ts:9

interface Env {
	VSCODE_REF: string;
	PRERELEASE_VERSION: string;
}

export function getNightlyEnv(): Env {
	const env: Env = process.env as any;
	if (!env.PRERELEASE_VERSION) {
		throw new Error(`Missing PRERELEASE_VERSION in process.env`);
	}
	if (!env.VSCODE_REF) {
		throw new Error(`Missing VSCODE_REF in process.env`);
	}
	return env;
}

View on GitHub (pinned to ca1b42dc89)

Solutions

1. Export the variable before running the script: `PRERELEASE_VERSION=<value> node scripts/ci/build-monaco-editor-core-pkg.ts nightly`.
2. In CI, add PRERELEASE_VERSION to the job's `env:` block or to the repository/organization secrets consumed by that job.
3. Verify the variable is non-empty (not just defined) — an empty string also triggers the throw.
4. If testing locally without a real prerelease, set a throwaway value like `0.0.0-dev-test` to satisfy the guard.

Example fix

// before
$ node scripts/ci/build-monaco-editor-pkg.ts nightly
// throws: Missing PRERELEASE_VERSION in process.env
// after
$ PRERELEASE_VERSION=0.34.0-dev.20240101 node scripts/ci/build-monaco-editor-pkg.ts nightly

if (!process.env.PRERELEASE_VERSION) {
  console.error('PRERELEASE_VERSION is required for nightly builds.');
  process.exit(2);
}
// then run the nightly build

function hasPrereleaseVersion(env: NodeJS.ProcessEnv): env is NodeJS.ProcessEnv & { PRERELEASE_VERSION: string } {
  return Boolean(env.PRERELEASE_VERSION);
}

When it happens

Trigger: Running the nightly build (`build-monaco-editor-core-pkg.ts nightly` or `build-monaco-editor-pkg.ts nightly`) in a shell or CI runner where PRERELEASE_VERSION is unset or empty. Also when a CI secret/variable was renamed or scoped to the wrong environment.

Common situations: CI workflow missing the env var in the nightly job; developer running nightly build locally without exporting the var; pipeline migrated to a new runner template that dropped the env injection; PRERELEASE_VERSION set on a different GitHub environment than the one the job uses.

Related errors

• Missing VSCODE_REF in process.env
• Invalid argument
• Invalid argument
• Cannot merge ${fieldName}: property '${key}' already exists

AI-assisted analysis of microsoft/monaco-editor@ca1b42dc89 (2026-08-13). Data as JSON: /api/errors/b28e6dba1ab00ba9. Report an issue: GitHub.