Meet Soni [off-list ref] writes:

test -f does not provide verbose error message on test failures, so use
test_path_is_file, test_path_is_missing instead.

While `test -f` checks to ensure that the file exists and is a regular
file, I also notice that the patch contains changing `test ! -f`. This
is a bit more tricky, since:
1. It can be used to check if a regular file doesn't exist
2. It can be used to check if a directory exists instead of a file

The commit message only talks about the former.

The patch itself look great, but I just noticed that the subject
mentions 'GSoC'. As Patrick has already mentioned in your previous email
to the list [1], we still don't have any plans with regards to GSoC 25.
So marking a patch in that context, doesn't make much sense (yet).

[1]: https://lore.kernel.org/git/Z2AwhvaE4DLAxzDy@pks.im/ (local)

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