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
# Balto (https://bitbucket.org/lothiraldan/balto/src) is a test orchestrator
# which is compatible with all test runner that can emit the LITF
# (https://github.com/lothiraldan/litf) test format.
# The plugin for the Mercurial test runner is mercurial-litf
# (https://pypi.org/project/mercurial-litf/). Make sure to follow the
# instruction and configuration instructions here:
# https://bitbucket.org/lothiraldan/mercurial_litf/src/default/
# You can launch Balto with `balto /path/to/mercurial/tests/`
name = "Mercurial Test Suite"
tool = "mercurial"