[BUG] ** glob pattern in git diff doesn't match root directory

From: Shoaib Meenai <smeenai@fb.com>
Date: Apr 24, 2021, 02:52 UTC
Message-ID: <79834D18-EAF4-4748-9B96-38AAA0760499@fb.com>

Hi all,

When I use a `**/` glob pattern with `git diff`, it doesn't seem to match in the root directory. The documentation for gitgnore says that a leading `**/` should match in all directories, and I would expect it to behave the same way for `git diff`. For example:

$ git --version git version 2.31.1.527.g47e6f16901 # built from the `next` branch $ mkdir /tmp/globtest && cd /tmp/globtest $ git init $ echo foo > foo $ mkdir sub $ echo subfoo > sub/foo $ git add . $ git commit -m 'Initial commit' $ echo bar > foo $ echo subbar > sub/foo $ git --no-pager diff '**/foo'

diff --git a/sub/foo b/sub/foo
index ef7889f..2b2ab6c 100644
--- a/sub/foo
+++ b/sub/foo
@@ -1 +1 @@
-subfoo
+subbar

Only the diff to `sub/foo` is printed, whereas I'd expect the change to
the top-level `foo` to be printed as well. `git diff '**foo'` does behave
as I would expect. This also happens with a `**` in the middle of a
pattern; e.g., `sub/**/bar` will match `sub/dir/bar` but not `sub/bar`.

Am I misunderstanding how `**` should work, or is this a bug?

Thanks,
Shoaib