Glob patterns w/ **; zero or more?

Glob patterns w/ **; zero or more?

[Maël Nison]

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.

Re: Glob patterns w/ **; zero or more?

[Andreas Schwab]

On Apr 16 2023, Maël Nison wrote:

> 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.

By default, pathspec matching does not take "**" specially, making it
equivalen to "*", but it can match "/".  Thus "./**/main.c" is the same
as "*/main.c" (the leading "./" always matches) and matches paths with
at least one "/" in it (thus "*/main.c" does not match "main.c").

If you use ":(glob)./**/main.c", it uses shell glob matching, where "**"
is special and "/**/" can match "/", but "*" does not match "/".

-- 
Andreas Schwab, schwab@linux-m68k.org
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