This is basic implementation. There's no config knob to enable the external
diff command by default. It reuses the merge-tools table because that's how
external diff/merge commands are currently configured. We might want to
reorganize them in #1285.
If you run "jj diff --tool meld", GUI diff will open and jj will wait for
meld to quit. This also applies to "jj log -p". The "diff --tool gui" behavior
is somewhat useful, but "log -p --tool gui" wouldn't. We might want some flag
to mark the tool output can't be streamed.
Another thing to consider is tools that can't generate directory diffs. Git
executes ext-diff tool per file, but we don't. Difftastic can compare
directories, and doing that should be more efficient since diffs can be
computed in parallel (at the expense of unsorted output.)
Closes#1886
I ran an upgraded Clippy on the codebase. All the changes seem to be
about using variables directly in format strings instead of passing
them as separate arguments.
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.
