phase: attach phase to the transaction instead of the lock
The phase cache file is no longer written on lock release, it is now handled by
the transaction (as changesets and obsolescence markers are).
(Hooray)
As we stop relying on the lock to write phase, repos with no existing phase
information will need to wait for a phase move or a strip to happen in order to
get the first write in the `phaseroots` file. This explain the change in
test-inherit-mode.t.
This should not have any side effects but in very obscure cases where
people interact with pre-2.1 and post-2.1 versions of Mercurial on the
same repo while having MQ patches applied but the MQ extension
disabled from time to time. A case unlikely enough to not be worth
preserving the old behavior with awful hacks.
$ rm -rf a
$ hg init a
$ cd a
$ echo a > a
$ hg ci -Am0
adding a
$ hg tag t1 # 1
$ hg tag --remove t1 # 2
$ hg co 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg tag -f -r0 t1
$ hg tags
tip 3:a49829c4fc11
t1 0:f7b1eb17ad24
$ cd ..