rust: less set lookups in AncestorsIterator
This uses the boolean return of `HashSet::insert()` to factor
pairs of contains()/insert() into a single insert()
On the mozilla-central repository (450k changesets), I get about a bit more
than 10% better medians in perfancestors (taking the mean of three runs)
Best run for parent changeset:
! wall 0.106474 comb 0.110000 user 0.110000 sys 0.000000 (median of 93)
Best run for this changeset:
! wall 0.093191 comb 0.090000 user 0.090000 sys 0.000000 (median of 100)
Differential Revision: https://phab.mercurial-scm.org/D5942
$ hg init a
$ cd a
$ hg init b
$ echo x > b/x
Should print nothing:
$ hg add b
$ hg st
$ echo y > b/y
$ hg st
Should fail:
$ hg st b/x
abort: path 'b/x' is inside nested repo 'b'
[255]
$ hg add b/x
abort: path 'b/x' is inside nested repo 'b'
[255]
Should fail:
$ hg add b b/x
abort: path 'b/x' is inside nested repo 'b'
[255]
$ hg st
Should arguably print nothing:
$ hg st b
$ echo a > a
$ hg ci -Ama a
Should fail:
$ hg mv a b
abort: path 'b/a' is inside nested repo 'b'
[255]
$ hg st
$ cd ..