branchcache: add a "pure topological head" fast path
In a narrow but actually quick common case, all topological heads are all on
the same branch and all open. In this case, computing the branch map is very
simple. We can quickly detect situation where this situation will not change.
So we update the V3 format to be able to express this situation and upgrade the
update code to detect we remains in that mode.
The branch cache is populated with the actual value when the branch map is
accessed, but the update_disk method can do the update without needing to
populate it.
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
generaldelta to generaldelta interactions with bundle2 but legacy clients
without changegroup2 support
$ cat > testcg2.py << EOF
> import sys
> from mercurial import changegroup, registrar, util
> cmdtable = {}
> command = registrar.command(cmdtable)
> @command('testcg2', norepo=True)
> def testcg2(ui):
> if not hasattr(changegroup, 'cg2packer'):
> sys.exit(80)
> EOF
$ cat >> $HGRCPATH << EOF
> [extensions]
> testcg2 = $TESTTMP/testcg2.py
> EOF
$ hg testcg2 || exit 80
$ cat > disablecg2.py << EOF
> from mercurial import changegroup, error, util
> deleted = False
> def reposetup(ui, repo):
> global deleted
> if deleted:
> return
> packermap = changegroup._packermap
> # protect against future changes
> if len(packermap) != 3:
> raise error.Abort('packermap has %d versions, expected 3!' % len(packermap))
> for k in ['01', '02', '03']:
> if not packermap.get(k):
> raise error.Abort("packermap doesn't have key '%s'!" % k)
>
> del packermap['02']
> deleted = True
> EOF
$ hg init master
$ hg debugrequires -R master | grep generaldelta
generaldelta
$ cd master
preferuncompressed = False so that we can make both generaldelta and non-generaldelta clones
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> [experimental]
> bundle2-exp = True
> [server]
> preferuncompressed = False
> EOF
$ echo x > x
$ hg commit -qAm x
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow -q --pull --config experimental.bundle2-exp=True
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ cd shallow
$ cat >> .hg/hgrc << EOF
> [extensions]
> disablecg2 = $TESTTMP/disablecg2.py
> EOF
$ cd ../master
$ echo y > y
$ hg commit -qAm y
$ cd ../shallow
$ hg pull -u
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets d34c38483be9
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ echo a > a
$ hg commit -qAm a
$ hg push
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files