fix: Sidecar の orphan process 化を防止 (parent process 監視) (Issue #7)

[oboroge0]

概要

検証中に SIGKILL でデスクトップ main プロセスを強制終了した際、Bun sidecar
プロセスが orphan 化 (PPID=1 launchd) して残存する問題を発見、修正します。

問題

これまでの実装 (apps/desktop/src-tauri/src/lib.rs):

.on_window_event(|window, event| {
    if window.label() == "main" && matches!(event, tauri::WindowEvent::Destroyed) {
        let state = window.state::<ServerProcess>();
        let mut guard = state.0.lock().unwrap();
        if let Some(child) = guard.take() {
            let _ = child.kill();
        }
    }
})

• 正常終了 (ユーザーがウィンドウを閉じる) では機能 ✅
• SIGKILL / Rust panic / OOM などの異常終了では event handler が走らない ❌
• macOS には Linux の prctl(PR_SET_PDEATHSIG) 相当機構が無いため、
  親プロセス死亡時に子プロセスへ自動通知できない

実機検証結果

$ ps -p 5633,14247 -o pid,ppid,stat,command
  PID  PPID STAT COMMAND
 5633  5412 S    target/debug/aituber-flow              # main
14247  5633 S    target/debug/server                    # sidecar (親=main)

$ kill -9 5633

$ ps -p 14247 -o pid,ppid,stat,command
  PID  PPID STAT COMMAND
14247     1 S    target/debug/server                    # ⚠️ PPID=1 (launchd) = orphan!

ユーザーが Force Quit / Activity Monitor 強制終了 / アプリクラッシュする度に
sidecar leak、port/DB ロック保持、メモリリーク発生。

修正内容

apps/desktop/src-tauri/src/lib.rs

+ // Pass our PID so the sidecar can self-terminate if we die ungracefully
+ // (SIGKILL, panic, etc.) — see apps/server-ts/src/index.ts parent-monitor.
+ let parent_pid = std::process::id();
let shell = handle.shell();
let (mut rx, child) = shell
    .sidecar("server")
    ...
    .env("AUDIO_DIR", audio_dir.to_string_lossy().to_string())
+   .env("AITUBERFLOW_PARENT_PID", parent_pid.to_string())
    .spawn()

apps/server-ts/src/index.ts

// Parent process monitoring: prevents orphan sidecar when the desktop main
// process is SIGKILLed, panics, or otherwise terminates without firing the
// Tauri WindowEvent::Destroyed handler. macOS lacks Linux's PR_SET_PDEATHSIG,
// so we poll explicitly. The Tauri side passes its PID via env var.
const parentPidEnv = process.env.AITUBERFLOW_PARENT_PID;
if (parentPidEnv) {
  const parentPid = Number(parentPidEnv);
  if (Number.isFinite(parentPid) && parentPid > 0) {
    console.log(`[parent-monitor] watching parent PID ${parentPid}`);
    setInterval(() => {
      try {
        process.kill(parentPid, 0); // signal 0 = existence check only
      } catch {
        console.log(`[parent-monitor] parent PID ${parentPid} no longer alive, exiting sidecar`);
        process.exit(0);
      }
    }, 1000).unref();
  }
}

動作

終了方法	既存 cleanup (WindowEvent)	新 cleanup (parent monitor)
ウィンドウ閉じる	✅ 即時	(走らない、必要なし)
アプリ終了メニュー	✅ 即時	(走らない、必要なし)
Force Quit	❌ 走らず (orphan)	✅ 最大1秒以内 (平均0.5秒)
SIGKILL	❌ 走らず (orphan)	✅ 最大1秒以内
Rust panic	❌ 走らず (orphan)	✅ 最大1秒以内

検証

• cargo check (apps/desktop/src-tauri) 成功 (7.85s, dev profile clean compile)
• 親監視ロジックを isolated test で検証 (non-existent PID 999999 → 1002ms で exit 確認)
• (このPR merge後の手動 E2E)
  • npm run dev:desktop → ps で sidecar の PPID=main 確認
  • kill -9 <main_pid> → 1秒以内に sidecar も終了することを確認
  • 通常終了 (ウィンドウ閉じ) も従来通り動作することを regression 確認

副次影響

• パフォーマンス: 1秒ごと kill(pid, 0) syscall 1回 = 無視できるレベル
• 既存の正常終了経路 (WindowEvent::Destroyed) は変更なし、両経路で cleanup
• AITUBERFLOW_PARENT_PID env が未設定 (sidecar を直接 bun run で起動した場合等) なら
  従来通り、stand-alone server モード互換

ロールバック

revert で完全復元可能。データ・成果物への影響なし。

関連

• 検証で発見された 7件の Issue のうち chore(deps): Bump openai from 1.10.0 to 2.15.0 in /apps/server #7 を修正
• PR fix: macOS の Auto-Updater が機能するよう bundle.targets に "app" を追加 #161 (macOS Updater)、chore: バージョンを 2.3.1 に統一しリリース手順 doc を更新 (Issue #1) #162 (バージョン統一)、refactor: devtools 機能を Cargo features 化し release ビルドから除外 (Issue #3) #163 (devtools cfg) と独立

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• apps/desktop/src-tauri/src/lib.rs
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