Glob patterns w/ **; zero or more?

From: Maël Nison <nison.mael@gmail.com>
Date: Apr 16, 2023, 18:40 UTC
Message-ID: <CANiF4iAaWB9j+Mma0-yfp6GvoQuM4k_OBAXn0keR+vCg8PQjmA@mail.gmail.com>

Hi,

I noticed that, in a repo with a single `main.c` file, `git ls-files './**/main.c'` (note the surrounding quotes, to avoid shell globbing) returns no result even though `git ls-files main.c` does. It however can find any `main.c` file located in a subdirectory, suggesting `**` is interpreted as "one or more" rather than "zero or more". Can you confirm it'd be a bug? I checked in both 2.38 and 2.40.

For reference, the documentation is explicit that `**` is "zero or more", not "one or more", and it matches the behaviour from other glob implementations (emphasis mine):

> A slash followed by two consecutive asterisks then a slash matches ***zero or
> more directories***. For example, "a/**/b" matches "a/b", "a/x/b", "a/x/y/b" and so on.

Also quoting the bash documentation for reference:

> globstar
> If set, the pattern ‘**’ used in a filename expansion context will match all files
> and zero or more directories and subdirectories. If the pattern is followed by
> a ‘/’, only directories and subdirectories match.