Re: git describe candidate filtering

"Shawn O. Pearce" [off-list ref] writes:

We only match things that were "added".  So if you don't add a tag
via add_to_known_names() then git-describe won't return it.

However that's only true for the standard case; for --contains its
a different story as we are actually passing everything to name-rev.

A good news is that name-rev is supposed to respect the name limiter.