Change event is fired when file is opened

[dominicpaul1911]

Describe the bug
Change event is fired when a file is opened.

When watching a folder, opening a file triggers a change event, even though the file has not been modified. Tested it with images, movies, text files etc.

Versions (please complete the following information):

• Chokidar version [e.g. 3.2.1 or commit hash] "chokidar": "^3.3.1"
• Node version [e.g. 12.11.0, ensure you are using the latest node.js] v12.11.1
• OS version: [e.g. Ubuntu 19.04 or MacOS 10.15 or Windows 10] MacOS 10.15.3

const chokidar = require('chokidar')

let TMP_WATCHER = chokidar.watch('/Users/dominic/code/test', {
    awaitWriteFinish: {
        stabilityThreshold: 2000,
        pollInterval: 100
    },
    alwaysStat: true,
})

TMP_WATCHER.on('add', (file, stats) => {
    console.log('add', file)
})

TMP_WATCHER.on('change', (file, stats) => {
    console.log('change', file)
})

Expected behavior
Should not fire change event unless there is a change in the file

[paulmillr]

Opened with what?

[dominicpaul1911]

Any respective application. For example images with Preview app, movie with Quick time, txt with Sublime etc.

[paulmillr]

Could you test this with 3.0 or 3.1?

[dominicpaul1911]

So the same behavior in previous versions as well. Digging in further looks like fs.watch has the same issue. Whenever a file opened, it fires a change event.

[paulmillr]

Interesting. Our low-level fsevents pkg reports unknown event when a file is opened, but no one reported this.

[pipobscure]

Is it possible that it's reporting an change of atime?

[Listor]

Yeah it is a change of atime but i don't think this is supposed to happen as described in this issue. Somehow it got closed for some reason #750 but this is still an issue.

[aspctu]

Just ran into this issue today with image files (.png to be specific). It occurs every time I open the file in Preview.

[taratatach]

Yes, it still happens for every kind of opening (even when folders are opened in Finder).

[AlexandreSi]

Just ran into this issue today with image files (.png to be specific). It occurs every time I open the file in Preview.

This is still the case today with version 3.5.3

[marbiano]

Still an issue in October 2023, anything we can do to help?

[paulmillr]

@marbiano unfortunately only a pull req