tests/test-merge6.t

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 <[e-mail]>

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.

  $ cat <<EOF > merge
  > import sys, os
  > print "merging for", os.path.basename(sys.argv[1])
  > EOF
  $ HGMERGE="python ../merge"; export HGMERGE

  $ hg init A1
  $ cd A1
  $ echo This is file foo1 > foo
  $ echo This is file bar1 > bar
  $ hg add foo bar
  $ hg commit -m "commit text"

  $ cd ..
  $ hg clone A1 B1
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd A1
  $ rm bar
  $ hg remove bar
  $ hg commit -m "commit test"

  $ cd ../B1
  $ echo This is file foo22 > foo
  $ hg commit -m "commit test"

  $ cd ..
  $ hg clone A1 A2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg clone B1 B2
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd A1
  $ hg pull ../B1
  pulling from ../B1
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m "commit test"
bar should remain deleted.
  $ hg manifest --debug
  f9b0e817f6a48de3564c6b2957687c5e7297c5a0 644   foo

  $ cd ../B2
  $ hg pull ../A2
  pulling from ../A2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg merge
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -m "commit test"
bar should remain deleted.
  $ hg manifest --debug
  f9b0e817f6a48de3564c6b2957687c5e7297c5a0 644   foo