This test is interesting because it already behaves as desired: since git has
rescheduled the "pick" command, we do _not_ want to show a "conflict" entry in
this case, as we would see the same commit twice then.
We don't actually use it to do map lookups; we still iterate over it in the same
way as before. However, using a map makes it easier to patch elements; see the
next commit.
We use CommitFilesController also for the files of commits that we show
elsewhere, e.g. for branch commits, tags, or stashes. It doesn't make sense to
discard changes from those (for stashes it might be possible to implement it
somehow, but that would be a new feature), so we disallow it unless we are in
the local commits panel.
Discarding changes to an entire directory doesn't quite work correctly in all
cases; for example, if the current commit added files to the directory (but the
directory existed before) then those files won't be removed.
It might be possible to fix the command so that these cases always work for
directories, but I don't think it's worth the effort (you can always use a
custom patch for that), so let's display an error for now.
I don't know why we were setting the initial context to CurrentSideContext
and not just CurrentContext in the first place. If there is no current context
in either case it'll default to the files context. So the only issue is if
we anticipated that some random context would be focused and we didn't want to
activate that. But I can't think of any situation where that would happen.
Whenever we perform an action in a test, we should assert on the result before doing the next action.
This prevents issues where the test moves too fast for our code. It would be nice to not have to do this,
but for now that's the situation
A better refactor would be to allow matchers to assert against either a string or a slice of cells, so that I could have
the same ergonomics that I have elsewhere, but this is a start.
The root commit is special in that it has no parents. So we need to add a pipe that's headed for a commit
that doesn't actually exist i.e. the mythical empty tree commit. We're using the actual hash of that
pseudo-commit, but it's not being read anywhere.
