Question UI psmux pane ${paneId} disappeared immediately aft

Error message

Question UI psmux pane ${paneId} disappeared immediately after launch.

What it means

Windows/psmux counterpart of the 'disappeared immediately' check: after creating the shell pane and waiting QUESTION_RENDERER_PANE_SETTLE_MS, isLaunchedQuestionPaneAlive reports it is gone. The psmux pane's shell or the command sent into it exited instantly, so the renderer cannot proceed.

Source

Thrown at src/question/renderer.ts:479

    returnTarget?: string;
    launchedAt: string;
  },
): QuestionRendererState {
  const rawPane = execTmux([
    'new-window',
    '-n',
    'OMX Question',
    '-P',
    '-F',
    '#{pane_id}',
    '-c',
    options.cwd,
  ]);
  const paneId = parsePaneIdFromTmuxOutput(rawPane);
  if (!paneId) throw new Error('Failed to create psmux question renderer shell pane.');
  sleepImpl(QUESTION_RENDERER_PANE_SETTLE_MS);
  if (!isLaunchedQuestionPaneAlive(paneId, execTmux)) {
    throw new Error(`Question UI psmux pane ${paneId} disappeared immediately after launch.`);
  }

  const command = buildWindowsPsmuxQuestionUiCommand(recordPath, options);
  for (const argv of buildSendPaneArgvs(paneId, command, false)) {
    execTmux(argv);
  }
  sleepImpl(QUESTION_TEXT_SETTLE_MS);
  execTmux(['send-keys', '-t', paneId, 'C-m']);

  return {
    renderer: 'tmux-pane',
    target: paneId,
    launched_at: options.launchedAt,
    ...(options.returnTarget ? { return_target: options.returnTarget, return_transport: 'tmux-send-keys' as const } : {}),
  };
}

function defaultSpawnDetachedRenderer(command: string, args: string[], options: SpawnOptions): Pick<ChildProcess, 'pid' | 'unref'> {

View on GitHub (pinned to 3ad79a8a6f)

Solutions

Run the generated Windows question UI command manually in a psmux pane to see the immediate failure.
Verify the OMX CLI entry path and node executable work under Windows shells (quoting, backslashes).
Ensure the psmux default shell exists (check COMSPEC/SHELL settings) and panes are not auto-closed.

Defensive patterns

Strategy: retry

Validate before calling

// manually test the generated command in a psmux pane:
// psmux split-window; then run buildWindowsPsmuxQuestionUiCommand output

Try / catch

try { launchQuestionRenderer(opts); } catch (e) { if (e instanceof Error && /psmux pane .* disappeared/.test(e.message)) { await delay(500); return launchQuestionRenderer(opts); } throw e; }

Prevention

Confirm the Windows shell (COMSPEC) is available to psmux panes.
Test the question UI command standalone before launching.
Quote Windows paths correctly in generated commands.

When it happens

Trigger: The psmux pane's shell exiting immediately (bad COMSPEC, shell not found, psmux closing empty panes); the follow-up question UI command (buildWindowsPsmuxQuestionUiCommand) failing to start because the OMX entry path is wrong on Windows; races with pane supersede.

Common situations: Windows CI/headless hosts where the default shell is unavailable; psmux configured with remain-on-exit off and a crashing command; path/quoting issues in the generated Windows command line.

Related errors

AI-assisted analysis of Yeachan-Heo/oh-my-codex@3ad79a8a6f (2026-08-27). Data as JSON: /api/errors/59882d359b34225d. Report an issue: GitHub.