branchmap: simplify _branchtags using a new _cacheabletip method
The current _branchtags method is a remnant of an older, much larger function.
Its only remaining role is to help MQ to alter the version of branchcache we
store on disk. As MQ mutates the repository it ensures persistent cache does not
contain anything it is likely to alter.
This changeset makes explicit the stable vs volatile part of repository and
reduces the MQ specific code to the computation of this limit. The main
_branchtags code now handles this possible limit in all cases.
This will help to extract the branchmap logic from the repository.
The new code of _branchtags is a bit duplicated, but as I expect major
refactoring of this section I'm not keen to setup factorisation function here.
http://mercurial.selenic.com/bts/issue1502
Initialize repository
$ hg init foo
$ touch foo/a && hg -R foo commit -A -m "added a"
adding a
$ hg clone foo foo1
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo "bar" > foo1/a && hg -R foo1 commit -m "edit a in foo1"
$ echo "hi" > foo/a && hg -R foo commit -m "edited a foo"
$ hg -R foo1 pull -u
pulling from $TESTTMP/foo (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
not updating: crosses branches (merge branches or update --check to force update)
$ hg -R foo1 book branchy
$ hg -R foo1 book
* branchy 1:e3e522925eff
Pull. Bookmark should not jump to new head.
$ echo "there" >> foo/a && hg -R foo commit -m "edited a again"
$ hg -R foo1 pull
pulling from $TESTTMP/foo (glob)
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
$ hg -R foo1 book
* branchy 1:e3e522925eff