Errors within add bubble as unhandled rejections

[bradymadden97]

Describe the bug

A clear and concise description of what the bug is.

Versions (please complete the following information):

• Chokidar version [e.g. 3.2.1 or commit hash] 3.6.0
• Node version [e.g. 12.11.0, ensure you are using the latest node.js] 20.9.0
• OS version: [e.g. Ubuntu 19.04 or MacOS 10.15 or Windows 10]

To Reproduce:

We have a number of these stack traces where an error occurs within the async function on this line:

Error: ENOSPC: System limit for number of file watchers reached, watch '/home/runner/Foodsource5/add_test_data.py'
  File "node:internal/fs/watchers", line 247, col 19, in FSWatcher.<computed>
  File "node:fs", line 2392, col 36, in Object.watch
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/lib/nodefs-handler.js", line 119, col 15, in createFsWatchInstance
    return fs.watch(path, options, handleEvent);
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/lib/nodefs-handler.js", line 166, col 15, in setFsWatchListener
    watcher = createFsWatchInstance(
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/lib/nodefs-handler.js", line 331, col 14, in NodeFsHandler._watchWithNodeFs
    closer = setFsWatchListener(path, absolutePath, options, {
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/lib/nodefs-handler.js", line 395, col 23, in NodeFsHandler._handleFile
    const closer = this._watchWithNodeFs(file, listener);
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/lib/nodefs-handler.js", line 637, col 21, in NodeFsHandler._addToNodeFs
    closer = this._handleFile(wh.watchPath, stats, initialAdd);
  File "../../../node_modules/.pnpm/[email protected]/node_modules/chokidar/index.js", line 451, col 21, in <anonymous>
    const res = await this._nodeFsHandler._addToNodeFs(path, !_internal, 0, 0, _origAdd);
  File "index 0", in Promise.all

It bubbles, but since add is sync, and there is no .catch on this line, its thrown to the global unhandled rejection handler. Would it be possible to update the API to allow callsites to handle this error more locally? Either make add async, add an error callback parameter, etc.?

I checked v4.0 and it appears the same code is still in place.

Thank you!

Expected behavior
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Additional context
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Optionally nice to know what project you are working on.

[43081j]

It would be a new major to make it async I think (breaking change). Maybe we could emit errors through the existing error handling?

Though you wouldn't have a direct connection between the call site and the error thrown, since it would be a separate event fired

Otherwise we would need to change add to take an optional callback or something

[aleclarson]

The current behavior of add is definitely problematic. I think making it async would be awesome. It would be a great replacement for the ready event, which is only emitted once even though I might want to watch multiple directories at various times throughout the lifecycle of the watcher.