node:fs/promises watcher polyfill is not AsyncIterable

[jldec]

Version: Deno 1.42.4

The deno polyfill for node fsPromises.watch() does not appear to return an AsyncIterator as documented here for node.

With deno run, using the returned watcher with for await throws TypeError: watcher is not async iterable. The same code works with node.

$ deno run fswatch-node.js
✅ Granted read access to <CWD>.
Watching for file changes in /Users/jldec/opral/deno, press Ctrl+C to exit.
error: Uncaught (in promise) TypeError: watcher is not async iterable
  for await (const event of watcher) {
                            ^
    at run (file:///Users/jldec/opral/deno/fswatch-node.js:8:29)
    at file:///Users/jldec/opral/deno/fswatch-node.js:13:1

$ node fswatch-node.js 
Watching for file changes in /Users/jldec/opral/deno-node-fs-promises-watch, press Ctrl+C to exit.
>>>> event { eventType: 'rename', filename: 'foo.bar' }

repro

fswatch-node.js from: https://github.com/jldec/deno-node-fs-promises-watch

import process from "node:process"
import fs from "node:fs/promises"

async function run() {
  const watcher = fs.watch(process.cwd(), { recursive: true })
  console.log(`Watching for file changes in ${process.cwd()}, press Ctrl+C to exit.`);

  for await (const event of watcher) {
    console.log(">>>> event", event)
  }
}

run()

Ref: https://github.com/denoland/deno/blob/main/ext/node/polyfills/_fs/_fs_watch.ts#L126C5-L126C18

[aguilera51284]

Is this issue still unreviewed? :(

[BlackAsLight]

Looking at the code in question it seems it would need to call .ref() on that return line https://github.com/denoland/deno/blob/main/ext/node/polyfills/_fs/_fs_watch.ts#L155, but it would be returning an async iterator for a Deno.FsEvent instead of a node one which has different property names.

[sntran]

I have also encountered this, and it seems that the watch in question was promisified instead of being an AsyncIterator like node:fs/promises.

await watch(path) does not fulfill the promise.