Fix Issue with recursive folders.

[johnathan-becker]

This PR addresses an issue in the NSDirectoryEnumerator where calling skipDescendents prematurely halts the directory enumeration process when the _stack data structure becomes empty. The root cause lies in the logic of skipDescendents, which previously removed the last item from _stack unconditionally when GSIArrayCount(_stack) > 0.

[johnathan-becker]

@qmfrederik Could you please review this. We have already QA'd it and it fixes the issue.

[qmfrederik]

Thanks @johnathan-becker!

Do we know why checking for GSIArrayCount(_stack) > 1 rather than GSIArrayCount(_stack) > 1 fixes the issue?
Looks like GNustep main keeps the check for GSIArrayCount(_stack) > 0 (see https://github.com/gnustep/libs-base/blob/master/Source/NSFileManager.m#L2859). Do you know if we can reproduce this issue with GNUstep main on Linux?

I just want to make sure we're not working around a potentially deeper issue (perhaps another subtle bug in libobjc2?).

Having said all that, since this change seems to be scoped to NSFileManager, I guess the risk for regressions is pretty isolated?

Frederik.

[johnathan-becker]

@qmfrederik We cannot reproduce the issue with GNUstep main on Linux. You are correct they did not change this on Master, but they also rewrote a lot of this code. The underlying issue might reside in the runtime, I am not sure. If you would like me to investigate further I am happy too we just know this fixes the issue and I do believe is a good change since when you remove the active pointer in skipDescendants you would normally expect undefined behavior.

[qmfrederik]

Let's take this as is for now (since it fixes the issue) but certainly something to keep int he back of our minds, I think.

[johnathan-becker]

That seems fair. Thank you for merging this. I am looking to get your changes merged into the gnustep_eggplant_branch today or tomorrow.