Function exec

src/node/runtime/LocalBaseRuntime.ts:54–210

(command: string, options: ExecOptions)

 */
export abstract class LocalBaseRuntime implements Runtime {
  async exec(command: string, options: ExecOptions): Promise<ExecStream> {
    const startTime = performance.now();

    if (options.abortSignal?.aborted) {
      throw new RuntimeErrorClass("Operation aborted before execution", "exec");
    }

    // Use the specified working directory (must be a specific workspace path)
    const cwd = options.cwd;

    // Check if working directory exists before spawning
    // This prevents confusing ENOENT errors from spawn()
    try {
      await fsPromises.access(cwd);
    } catch (err) {
      throw new RuntimeErrorClass(
        `Working directory does not exist: ${cwd}`,
        "exec",
        err instanceof Error ? err : undefined
      );
    }

    const bashPath = getBashPath();
    const spawnCommand = bashPath;

    // Match RemoteRuntime behavior: ensure non-interactive env vars are set inside the shell.
    //
    // Why not rely solely on `env`?
    // - On Windows, env var casing and shell startup state can be surprising.
    // - These are non-sensitive vars that we want to guarantee for git/editor safety.
    const nonInteractivePrelude = Object.entries(NON_INTERACTIVE_ENV_VARS)
      .map(([key, value]) => buildShellExport(key, value))
      .join("\n");

    const spawnArgs = ["-c", `${nonInteractivePrelude}\n${command}`];

    const defaultPath = "/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin";
    const mergedEnv = sanitizeMuxChildEnv({ ...process.env, ...(options.env ?? {}) });
    const basePath =
      (options.env?.PATH && options.env.PATH.length > 0
        ? mergedEnv.PATH
        : (mergedEnv.PATH ?? mergedEnv.Path)) ?? defaultPath;
    const effectivePath = basePath;

    const childProcess = spawn(spawnCommand, spawnArgs, {
      cwd,
      env: {
        ...mergedEnv,
        ...NON_INTERACTIVE_ENV_VARS,
        PATH: effectivePath,
      },
      stdio: ["pipe", "pipe", "pipe"],
      // CRITICAL: Spawn as detached process group leader to enable cleanup of background processes.
      // When a bash script spawns background processes (e.g., `sleep 100 &`), we need to kill
      // the entire process group (including all backgrounded children) via process.kill(-pid).
      // NOTE: detached:true does NOT cause bash to wait for background jobs when using 'exit' event
      // instead of 'close' event. The 'exit' event fires when bash exits, ignoring background children.
      detached: true,