React Native 项目 Error: EMFILE: too many open files, watch

硬件：MacBook Pro (Retina, 13-inch, Mid 2014)
OS版本：MacOS BigSur 11.7.10 (20G1427)
更新: 删除modules的方法会有反弹，最后还是手动安装了预编译版本的watchman。

React Native 项目运行npm run web，出现如下错误：

Your macOS system limit does not allow enough watchers for Metro, install Watchman instead. Learn more: https://facebook.github.io/watchman/docs/install
Error: EMFILE: too many open files, watch

尝试了如下方案：

1. 尝试 npm install watchman
   提示npm warn deprecated watchman@1.0.0: Package no longer supported. Contact support@npmjs.com for more info.

2. 尝试brew install watchman
   无法安装，提示我的系统版本太老
   

3. 尝试修改文件打开数量（需要进入恢复模式关闭SIP: csrutil disable ）：
   sudo launchctl limit maxfiles 5000000 5000000
   通过launchctl limit maxfiles查看已经改好了，但是仍然提示同样错误。

4. 删除模块：

rm -rf node_modules/
npm install

然后再次npm run web，终于可以了：

但是后面调试过程中安装了别的模块之后，这个问题又回来了。

4. 手动安装watchman
   点击官方链接下载macOS的prebuild版本Release v2023.05.01.00 · facebook/watchman（后面已经没有新版本了）
   然后复制到/usr/local/Cellar/,

cd /usr/local/Cellar/
unzip watchman-v2023.05.01.00-macos.zip
mv watchman-v2023.05.01.00 watchman
cp /usr/local/Cellar/watchman/lib/*.*  /usr/local/lib
brew link watchman

此时如果运行watchman --version报错找不到，那就手动创建链接：

ln -s /usr/local/Cellar/watchman/*/bin/watchman /usr/local/bin/watchman

然后再次运行watchman --version检查。
然后watchman config(其实没有这个命令)，会提示：

watchman config   
2025-01-05T11:12:13,985: [] while computing sockname: failed to create /usr/local/var/run/watchman/xxx-state: Permission denied

其中xxx是我的系统用户名。
所以需要这样：

sudo spctl --master-disable
sudo chown -R $(whoami) /usr/local/var/run/watchman

然后再次运行watchman config，会提示没这个命令

watchman config                                    
{"version": "20230430.125247.0","error": "watchman::CommandValidationError: failed to validate command: unknown command config"
}

但是watchman可以正常工作了，npx expo start也没有文件打开太多的错误了。
可以使用watchman debug-status命令查看watchman状态：

watchman debug-status
ROOTS
-----
/Users/simonliu/Documents/AI/AICoding/cursor/projects/rn1- fstype: apfs- watcher: fsevents- uptime: 7709 s- crawl_status: crawl completed 7707330ms ago, and took 1864ms- done_initial: trueCLIENTS
-------
57960: 'watchman' 'debug-status'- since: 2025-01-05 13:24:42- state: dispatching command54201: 'node' '/Users/simonliu/Documents/AI/AICoding/cursor/projects/rn1/node_modules/.bin/expo' 'start' '--reset-cache'- since: 2025-01-05 11:16:17- state: waiting for request

参考文献：

1. ios - React Native Error: EMFILE: too many open files, watch - Stack Overflow
2. MacOS binaries missing · Issue #1190 · facebook/watchman