phases: update the phase set as we go during retract boundary Apparently iterating over the `changed_revs` dictionary is very expensive. On mozilla-try-2019-02-18, a perf::unbundle call with a 10 000 changesets bundle gives give use the following timing. e57d4b868a3e: 4.6 seconds ac1c75188440: 102.5 seconds prev-changeset: 30.0 seconds this-changeset: 4.6 seconds So, the performance regression is gone. Once again: thanks to marvelous Python!

#require clang-format test-repo

  $ . "$TESTDIR/helpers-testrepo.sh"

  $ cd "$TESTDIR"/..
  $ for f in `testrepohg files 'set:(**.c or **.cc or **.h) and not "listfile:contrib/clang-format-ignorelist"'` ; do
  >   clang-format --style file $f > $f.formatted
  >   cmp $f $f.formatted || diff -u $f $f.formatted
  >   rm $f.formatted
  > done