Re: Merge conflicts in .gitattributes can cause trouble

Johannes Schindelin [off-list ref] writes:

To the contrary. As far as I can see, when calling `git merge`, Git
currently *does* read .gitattributes from the file, and if that fails,
falls back to reading that file from the index.

Hmph.

Assuming that the merge always goes in the index order, I think you
are right.  When we need to merge path/to/dir/.gitattributes, we
would need to know all the .gitattributes files that may affect that
path, so .gitattributes, path/.gitattributes, path/to/.gitattributes
and the file being merged are all read into core before anything
happens and these are kept in attr_stack while merging anything
underneath path/to/dir/ hierarchy without being re-read from the
filesystem.  The original contents of path/to/dir/.gitattributes
cached in the attr_stack will be discarded when we start to merge
things outside path/to/dir (e.g. merging path/to/another/file), but
at that point the contents of path/to/dir/.gitattributes no longer
matters to the path being merged, so unless the merge somehow jumps
around it is OK.

It may be a fragile assumption in the longer term that the merge
always goes in the index order, but I think the assumption holds in
the current codebase, and the update planned immediately in the
future.