`BranchName` provides the nearest branch of the requested `:commit`.
It's plenty fast on smaller repositories.
On larger repositories like nixpkgs, however, this can easily take 2-3
seconds on a modern machine on a NVMe.
For context, at the time of writing, nixpkgs has over 650k commits and
roughly 250 branches.
`BranchName` is used once in the whole view:
The cherry-pick target branch default selection.
And I believe that's a logic error, which is why this patch is so small.
The nearest branch of a given commit will always be a branch the commit
is already part of. The branch you most likely *don't* want to
cherry-pick to.
Sure, one can technically cherry-pick a commit onto the same branch, but
that simply results in an empty commit.
I don't believe this is intended and even less so worth the compute.
Instead, the cherry-pick branch selection suggestion now always uses
the default branch, which used to be the fallback.
If a user wants to know which branches contain the given commit,
`load-branches-and-tags` exists and should be used instead.
Also, to add insult to injury, `BranchName` was calculated for both
logged-in and not logged-in users, despite its only consumer, the
cherry-pick operation, only being rendered when a given user has
write/commit permissions.
But this isn't particularly surprising, given this happens a lot in
Forgejo's codebase.
c1f85ce27b