Re: [PATCH 2/2] ref-filter: support filtering of operational refs

[Taylor Blau <me@ttaylorr.com>]

On Tue, Jan 02, 2024 at 07:18:48AM -0800, Karthik Nayak wrote:
> > As "git for-each-ref" takes pattern that is prefix match, e.g.,
> >
> >     $ git for-each-ref refs/remotes/
> >
> > shows everything like refs/remotes/origin/main that begins with
> > refs/remotes/, I wonder if
> >
> >     $ git for-each-ref ""
> >
> > should mean what you are asking for.  After all, "git for-each-ref"
> > does *not* take "--branches" and others like "git log" family to
> > limit its operation to subhierarchy of "refs/" to begin with.
>
> But I don't think using an empty pattern is the best way to go forward.
> This would break the pattern matching feature. For instance, what if the
> user wanted to print all refs, but pattern match "*_HEAD"?
>
> Would that be
>
>       $ git for-each-ref "" "*_HEAD"
>
> I think this would be confusing, since the first pattern is now acting
> as an option, since its not really filtering rather its changing the
> search space.
>
> Maybe "--all-refs" or "--all-ref-types" instead?

I tend to agree that the special empty pattern would be a good shorthand
for listing all references underneath refs/, including any top-level
psuedo-refs.

But I don't think that I quite follow what Karthik is saying here.
for-each-ref returns the union of references that match the given
pattern(s), not their intersection. So if you wanted to list just the
psudo-refs ending in '_HEAD', you'd do:

  $ git for-each-ref "*_HEAD"

I think if you wanted to list all pseudo-refs, calling the option
`--pseudo-refs` seems reasonable. But if you want to list some subset of
psueod-refs matching a given pattern, you should specify that pattern
directly.

Thanks,
Taylor