[IncludeTreeFileSystem] Make dir_begin() work as expected in OverlayFileSystem

[cachemeifyoucan]

Make dir_begin() in IncludeTreeFileSystem to return no_such_file_or_directory instead of operation_not_permitted. This allows OverlayFileSystem to correctly ignore IncludeTreeFileSystem layer and continue to search the layer below.

rdar://127370903

[cachemeifyoucan]

@swift-ci please test

[cachemeifyoucan]

@swift-ci please test macOS platform

[akyrtzi]

Could you clarify a bit, what is the "swift overlay yaml file" and how is it setup, it's not reading the file system right?

Also were you really intending to merge on stable/20230725? I thought this is not useful anymore.

[benlangmuir]

I think we should add a unit test for this.

[benlangmuir]

Also were you really intending to merge on stable/20230725? I thought this is not useful anymore.

@akyrtzi this is still the branch that swift main builds with.

[akyrtzi]

@akyrtzi this is still the branch that swift main builds with.

Ok, thanks for letting me know! But I'd expect a PR on next and then cherry-pick to stable/20230725.

[cachemeifyoucan]

Could you clarify a bit, what is the "swift overlay yaml file" and how is it setup, it's not reading the file system right?

This is not about the vfs overlay from yaml file. It is creating a OverlayFileSystem using two different file systems. For example, if you overlay include tree file system on top of real file system, dir_begin is going to error out on include tree layout and you can't iterate file system underneath that is not part of the include tree.

I think we should add a unit test for this.

Unit test is a bit tricky as the only way to create it is from clang dependency scanner. Let me see if I can do something about it.

[cachemeifyoucan]

@swift-ci please test

[cachemeifyoucan]

@swift-ci please test windows platform