As we have discussed many times on Discord and GitHub, `--destination`
is not a great name because `--insert-before` and `--insert-after` are
also destinations. The most popular alternative seems to be
`--onto`. We already use that term in descriptions in several places,
such as in the help text for `rebase -d` where we say "The revision(s)
to rebase onto". This patch therefore renames the `--destination` flag
to `--onto`.
The short name naturally becomes `-o`. That is perhaps a little
unfortunate because it's a common short name for `--output <file>`
arguments, but we don't use that anywhere so it seems fine.
Perhaps we should also rename `--source` (used by `rebase` and `fix`)
to something else. Perhaps the most obvious name is `--descendants`,
but the short form would be `-d`, which is of course already taken by
`--destination` in the case of `rebase`. Either way, I'm leaving that
rename for later. It would be good to do it before next release if we
are going to do it, though.
Closes#7941
This version describes a design that I think will work relatively well
for supporting copy tracing even when there are conflicts.
There are still some open questions, in particular around how to
populate the data in Git repos, and how to efficiently query the data
in very large repos like the one at Google. I think it's still clear
enough that we can start working on the implementation.