File name disappears in git version 2.38.1

[Cat Chen]

Broken version: git version 2.38.1
Working version: git version 2.37.1 (Apple Git-137.1)

git diff output is slightly different between these two versions. In the working version, it's like this:

diff --git a/modified.txt b/modified.txt
index 1dd297ad..1cb605b6 100644
--- a/modified.txt
+++ b/modified.txt

In the broken version, it's like this:

diff --git modified.txt modified.txt
index 12ea6ab..c801668 100644
--- modified.txt
+++ modified.txt

The a/ and b/ are gone. git-split-diffs fails to parse the file name when a/ and b/ are gone and thus displaying every file without a file name. Otherwise, everything else still works.

[Shrey Banga]

I just updated to git 2.39.0 and still don't see this behavior. I see your fix, but unfortunately it breaks a test case (file deletion). Can you share more detailed repro steps and any special config settings you might have (check git config -l)?