mq: restore _branchtags() fast path (issue3223)
Since a5917346c72e, mq saves the nodeid of the first applied patch to
cache/branchheads, which breaks the optimized cache handling introduced in
fbf8320f25c8. The problem is the revision being committed is appended to
mqrepo.applied after the commit succeeds, which means mqrepo._branchtags()
performs a regular update and write the first applied patch to the branch
cache.
One solution is to set a context variable _committingpatch on the mqrepo while
it is committing a patch and to take it in account when deciding to fast-path
mqrepo._branchtags(). Not really elegant but it works.
The changes to test-mq-caches.t reverse changes introduced by a5917346c72e. The
cache should not have been updated with mq records.
The changes to test-keyword.t are indirectly caused by a5917346c72e.
Reported and analyzed by Yuya Nishihara <yuya@tcha.org>
Notes:
- qpush still makes a slow path _branchtags() call when checking heads. Maybe
this can be optimized.
- be careful when merging this patch in default as secretcommit() was renamed
newcommit() right after the end of the code freeze.
[ original upstream message ]