phases: improve performance of _retractboundary The old version repeatedly converts nodes to revisions, which is a moderately expensive operation. Mapping all new changes once to revisions and back at the end reduces the time spend in _retractboundary during the unbundling of NetBSD's src from 67s to 17s. Differential Revision: https://phab.mercurial-scm.org/D8641

tests: use proctutil.stdout.write() instead of print() in test-extension.t I was debugging this test failure on python3 + chg. I get the following hunk as test failure: ``` @@ -206,6 +206,18 @@ Check normal command's load order of ext 4) bar uipopulate 5) foo reposetup 5) bar reposetup + 4) foo uipopulate (chg !) + 4) bar uipopulate (chg !) + 4) foo uipopulate (chg !) + 4) bar uipopulate (chg !) + 4) foo uipopulate (chg !) + 4) bar uipopulate (chg !) + 4) foo uipopulate (chg !) + 4) bar uipopulate (chg !) + 4) foo uipopulate (chg !) + 4) bar uipopulate (chg !) + 5) foo reposetup (chg !) + 5) bar reposetup (chg !) 0:c24b9ac61126 ``` After hours of debugging and head scracthing, I figured out that something is wrong with output flushing. I initially switched the print() statements to ui.warn() but thanks to Yuya who suggested using procutil.stdout.write() instead.

fuzz: tell manifest fuzzer about longer node hashes Differential Revision: https://phab.mercurial-scm.org/D8374

absorb: preserve changesets which were already empty Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty changesets or drop them if they become empty. If there’s a changeset that’s empty, it must be a deliberate choice of the user. At least it shouldn’t be absorb’s responsibility to prune them. The fact that changesets that became empty during absorb are pruned, is unaffected by this. This case was found while writing patches which make it possible to configure absorb and rebase to not drop empty changesets. Even without having such config set, I think it’s valuable to preserve changesets which were already empty.

absorb: preserve branch-closing changesets even if empty This makes the behavior consistent with 'hg commit', which allows to create otherwise empty changesets if they close the branch. A lost branch closure can inadvertently re-open a branch, so it should be preserved.

absorb: preserve branch-changing changesets even if empty This makes the behavior consistent with 'hg commit', which allows to create otherwise empty changesets if the branch changes compared to the parent. A branch change can denote important information, so it should be preserved.