support character classes in `gix::refspec::parse`

[nrdxp]

Current behavior 😯

so I'm not sure if maybe I am not doing it right, but I know git servers support queries which can include wildcards and character classes as a sort of minimal subset of more complex regex.

As far as I can tell though, any attempt to actually query a remote with a character class fails, and it seems to be when I parse a string to a RefSpecRef via gix::refspec::parse. I get the error: "A reference must be a valid tag name as well"

Expected behavior 🤔

Ideally we should support any kinda of query a git server can support including character classes.

Git behavior

for example git ls-remote origin "refs/tags/v[0.9]* would return all tags that sorta look like a version

Steps to reproduce 🕹

Just include a character class in a call to the aforementioned parse function.

[Byron]

Thanks so much for making me aware of this feature!

It is true that Git globs include character classes, Gitoxide also implements them, and that it's possible to pass specs with globs to the server.

Doing the same with gix today results in the following:

❯ gix remote ref-map "refs/tags/v[0.9]*"
Error: A reference must be a valid tag name as well

Caused by:
    A ref must not contain invalid bytes or ascii control characters: "["

Git on the other hand is fine with it:

❯ git ls-remote origin "refs/tags/v[0.9]*"
2ecf0dbadd08cf56c749663ff511d25f268de01b        refs/tags/v0.0.24
f8c04842e5fa921cac398e4a37103644b5d84072        refs/tags/v0.0.25
a7d283ff6fca28e05c0ac0dbebd90596280c18a7        refs/tags/v0.1.0
[..]

But there is more:

❯ git ls-remote origin "refs/tags/v*"
e2ecf0dbadd08cf56c749663ff511d25f268de01b       refs/tags/v0.0.24
f8c04842e5fa921cac398e4a37103644b5d84072        refs/tags/v0.0.25
a7d283ff6fca28e05c0ac0dbebd90596280c18a7        refs/tags/v0.1.0
[..]

❯ gix remote ref-map "refs/tags/v*"
Error: Both sides of the specification need a pattern, like 'a/*:b/*'

This basically is a whole new class of refspecs, i.e. refspecs which don't follow the typical pattern and that are just globs, effectively. Maybe this is also something special for git ls-remote which gix doesn't try to emulate with its remote ref-map subcommand.

However, since this works:

❯ gix remote ref-map "refs/heads/master"
 04:45:48 remote-refs Connecting to "https://github.com/Byron/gitbutler"
refs/heads/master
        3377495f544a2e166792638ff988bf53d5516708 refs/heads/master (fetch only)
server sent 40 tips, 39 were filtered due to 1 refspec(s).

I think that globs should also work. Maybe this could be implemented by a new type of refspec, one that is just a glob with everything allowed in it.