Re: bug report

[Paul Smith <paul@mad-scientist.net>]

On Fri, 2021-11-12 at 01:59 -0500, Theodore Li wrote:
> Yes, though other patterns like !/*/ don't need the quotes. I thought
> it worked the same way without the quotes in earlier versions, but
> after testing with version 2.32.0, it seems like the behavior is the
> same. Guess I remembered wrong.

It's important to realize that in a POSIX-style shell (as you'll find
on GNU/Linux or MacOS, or in the Git for Windows shell), wildcard
expansion is performed _by the shell_ before the program is even
invoked.  It's not performed by the program itself (in this case, Git).

In a POSIX-style shell it works like this (by default): first the shell
will try to expand the wildcards in your command line by matching them
for files.  If any match, the wildcard expression is replaced on the
command line.  If no files match, then the wildcard expression is
passed to the command without change.

So if you run:

  git sparse-checkout /*

then the shell will check if any files match the wildcard /*: since
clearly you will get matches for this expression, they will be expanded
and the shell will actually run:

  git sparse-checkout /bin /boot /cdrom /dev /...

Note, Git does not receive any indication that there ever was a
wildcard expression here!

On the other hand if you run:

  git sparse-checkout /blah/*/blah

(assuming you don't have any files on your system that match this
wildcard) then it won't match and the shell will run:

  git sparse-checkout /blah/*/blah

Now Git can examine this wildcard and do an appropriate thing with it.

In short, if you want to be _sure_ that a wildcard expression is passed
to the command and not expanded by the shell, you must always quote it:

  git sparse-checkout "/*"

If you don't quote it then it may or may not do what you intended,
depending on whether the wildcard happens to match any files.