Function doInstallInjectedDevPackage

packages/python/src/start-dev-server.ts:338–426

(
  pkg: InjectedPackageSpec,
  opts: DevPythonOptions & { targetDir: string }
)

}

async function doInstallInjectedDevPackage(
  pkg: InjectedPackageSpec,
  opts: DevPythonOptions & { targetDir: string }
): Promise<void> {
  const { targetDir, workPath, uvPath, pythonBin, env, onStdout, onStderr } =
    opts;
  mkdirSync(targetDir, { recursive: true });

  const localDir = join(__dirname, '..', '..', '..', 'python', pkg.name);
  const isLocalDev = existsSync(join(localDir, 'pyproject.toml'));

  const dep =
    pkg.envOverride ||
    (isLocalDev ? localDir : `${pkg.name}==${pkg.pinnedVersion}`);

  // Skip install if the exact pypi version is already present;
  // local dev builds and explicitly specified versions
  // always reinstall to pick up possible source changes.
  if (!isLocalDev && !pkg.envOverride) {
    const distInfoName = pkg.name.replace('-', '_');
    const distInfo = join(
      targetDir,
      `${distInfoName}-${pkg.pinnedVersion}.dist-info`
    );
    if (existsSync(distInfo)) {
      debug(`${pkg.name} ${pkg.pinnedVersion} already installed, skipping`);
      return;
    }
  }

  debug(
    `Installing ${pkg.name} into ${targetDir} (type: ${isLocalDev ? 'local' : 'pypi'}, source: ${dep})`
  );

  const pip = uvPath
    ? { cmd: uvPath, prefix: ['pip', 'install'] }
    : { cmd: pythonBin, prefix: ['-m', 'pip', 'install'] };

  // Override exclude-newer so a project-level date constraint doesn't
  // block installation of a recently-published injected package.
  const excludeOverride = uvPath
    ? ['--exclude-newer-package', `${pkg.name}=false`]
    : [];

  const spawnArgs = [
    ...pip.prefix,
    '--target',
    targetDir,
    ...excludeOverride,
    dep,
  ];

  await new Promise<void>((resolve, reject) => {
    const child = spawn(pip.cmd, spawnArgs, {
      cwd: workPath,
      env: getProtectedUvEnv(env),
      stdio: ['inherit', 'pipe', 'pipe'],
    });