tests/test-double-merge.out

localrepo.commit: grab locks before getting the list of files to commit

Somebody may change the dirstate after we've determined the parents of
the working dir and run repo.status, but before we called wlock().

This should also fix issue997, where backout would change a file without
changing its size and then call repo.commit without passing the list of
files. If this happened in less than one second, we wouldn't detect any
file changes - the in-memory dirstate still has the cached stat data for
that file. Grabbing the wlock early causes the dirstate to be
invalidated and we end up reading the dirstate file again, which has
that file marked for lookup (size == -1).

A better fix would be for backout to give repo.commit the exact list of
files, but that'll require some changes to the revert operation.

A significant user-visible change is that the precommit hook is always
run with both locks grabbed - previously, hg commit would run it before
grabbing any locks, but hg import would run it after grabbing locks.

created new head
resolving manifests
 overwrite None partial False
 ancestor 310fd17130da local 2092631ce82b+ remote 7731dad1c2b9
  searching for copies back to rev 1
  unmatched files in other:
   bar
  all copies found (* = to merge, ! = divergent):
   bar -> foo *
  checking for directory renames
 foo: versions differ -> m
 foo: remote copied to bar -> m
copying foo to bar
picked tool 'internal:merge' for foo (binary False symlink False)
merging foo and bar
my foo@2092631ce82b+ other bar@7731dad1c2b9 ancestor foo@310fd17130da
 premerge successful
picked tool 'internal:merge' for foo (binary False symlink False)
merging foo
my foo@2092631ce82b+ other foo@7731dad1c2b9 ancestor foo@310fd17130da
 premerge successful
0 files updated, 2 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
-- foo --
line 0
line 1
line 2-1
-- bar --
line 0
line 1
line 2-2