revset: add 'only' revset...
revset: add 'only' revset
Adds a only() revset that has two forms:
only(<set>) is equivalent to "::<set> - ::(heads() - heads(<set>::))"
only(<include>,<exclude>) is equivalent to "::<include> - ::<exclude>"
On a large repo, this implementation can process/traverse 50,000 revs in 0.7
seconds, versus 4.2 seconds using "::<include> - ::<exclude>".
This is useful for performing histedits on your branch:
hg histedit -r 'first(only(.))'
Or lifting branch foo off of branch bar:
hg rebase -d @ -s 'only(foo, bar)'
Or a variety of other uses.
