This allows us to use "if(description,)" to test empty description. And
I think this change is unavoidable if we want to add support for commit
template.
Since CR+LF vs LF things shouldn't matter in commit description, it's probably
better to normalize newline characters.
In Mercurial, ui.edit() and changelog.stripdesc() handle line normalization,
and trailing newlines are stripped. In Git, cleanup_message() handles that,
and the last newline is added after stripping trailing newlines.
Otherwise the description set by -m would differ from the one set by editor.
This fixes test_describe() which says "make no changes", but previously "\n"
would be added by the second "jj describe".
As you can see, almost all hashes change in CLI tests. This means in-flight
PRs will need to be rebased to update insta snapshots.
Description text could be normalized by CommitBuilder, but the caller would
have to normalize it beforehand to compare with the current description, so
we would need an explicit function anyway. Another idea is to add a newtype
that represents a normalized description, and make CommitBuilder require it.
Commit::description() will return &Description in place of &str to ensure
that commit.description() == raw_str wouldn't compile.
Git CLI provides --cleanup=<mode> option to switch normalization rules, but
I don't think we'll need such feature.
Let's acknowledge everyone's contributions by replacing "Google LLC"
in the copyright header by "The Jujutsu Authors". If I understand
correctly, it won't have any legal effect, but maybe it still helps
reduce concerns from contributors (though I haven't heard any
concerns).
Google employees can read about Google's policy at
go/releasing/contributions#copyright.
It seems very likely that we're going to remove support for open
commits, but it's still useful to have a `commit` command that lets
the user enter a description and starts a new change. Calling it
`commit` seems good to make the transition from other VCSs simpler.
