Function checkVenvModule

src/python-env.ts:70–95

(pythonExe: string = resolvePythonExe())

 * exact package name (`python3.12-venv` for Python 3.12).
 */
export function checkVenvModule(pythonExe: string = resolvePythonExe()): VenvModuleCheck {
  const result: VenvModuleCheck = { available: false };

  const version = spawnSync(
    pythonExe,
    ['-c', "import sys; print(f'{sys.version_info.major}.{sys.version_info.minor}')"],
    { encoding: 'utf-8' },
  );
  if (version.status !== 0 || version.error) {
    // The interpreter itself could not run — that is a "python not available"
    // problem, not a "venv module missing" one. Report available=true so the
    // caller's normal flow surfaces the real interpreter error rather than a
    // misleading apt hint.
    result.available = true;
    return result;
  }
  const parsed = version.stdout.trim();
  if (/^\d+\.\d+$/.test(parsed)) result.pythonVersion = parsed;

  // `import ensurepip, venv` is the classic missing-python3-venv tripwire on
  // Debian: the venv module is present in stdlib but ensurepip is shipped in
  // the separate `python3-venv` apt package.
  const probe = spawnSync(pythonExe, ['-c', 'import ensurepip, venv'], { encoding: 'utf-8' });
  result.available = probe.status === 0 && !probe.error;
  return result;
}

/**
 * Returns true when the given stderr is the recognizable "python3-venv package