Incorrect event firing on macOS when filename case changes

[george-thomas-hill]

On a case-insensitive (i.e. typical) APFS drive, when a filename changes case, incorrect events fire.

If a filename starts off as "scratch.txt", when it is changed to "Scratch.txt" the following events fire:

change /Users/georgehill/Desktop/parent/scratch.txt
add /Users/georgehill/Desktop/parent/Scratch.txt

However, I would expect to see:

unlink /Users/georgehill/Desktop/parent/scratch.txt
add /Users/georgehill/Desktop/parent/Scratch.txt

If the file is then changed from "Scratch.txt" to "SCratch.txt", the following events fire:

change /Users/georgehill/Desktop/parent/Scratch.txt
add /Users/georgehill/Desktop/parent/SCratch.txt

That is consistent with the events that fired when going from "scratch.txt" to "Scratch.txt".

However, if the filename later changes from "SCRatch.txt" back to "scratch.txt" (e.g. a prior casing), then the following events fire:

change /Users/georgehill/Desktop/parent/SCRatch.txt
change /Users/georgehill/Desktop/parent/scratch.txt

Notice that this change is not consistent with the prior changes: it's two change events, not a change followed by an add.

Versions (please complete the following information):

• Chokidar version: 3.5.3
• Node version: 18.13.0
• OS version: macOS 12.6.3

To Reproduce:

See above.

I used the following simple index.js code:

const chokidar = require('chokidar');

chokidar.watch('/Users/georgehill/Desktop/parent').on('all', (event, path) => {
    console.log(event, path);
});

And I started with a file named "scratch.txt".

Expected behavior

See above.

Additional context

I expect that this problem occurs because typical macOS drives are case insensitive.

[pedroferreira37]

Hi, @george-thomas-hill

This kind of issue usually happens in directories, exactly as you mentioned. In your case, since we talking about files, it appears to be a design choice rather than a problem with the SO. In the event 'all', seems that it only triggers for event 'change' and event 'add'. I think this could actually be considered a feature implementation request.

Having spent some time familiarizing myself with the codebase, I want to contribute and would like to offer my help in this issue.