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.
$ cat > bundle2.py << EOF
> """A small extension to test bundle2 pushback parts.
> Current bundle2 implementation doesn't provide a way to generate those
> parts, so they must be created by extensions.
> """
> from mercurial import bundle2, exchange, pushkey, util
> def _newhandlechangegroup(op, inpart):
> """This function wraps the changegroup part handler for getbundle.
> It issues an additional pushkey part to send a new
> bookmark back to the client"""
> result = bundle2.handlechangegroup(op, inpart)
> if b'pushback' in op.reply.capabilities:
> params = {b'namespace': b'bookmarks',
> b'key': b'new-server-mark',
> b'old': b'',
> b'new': b'tip'}
> encodedparams = [(k, pushkey.encode(v))
> for (k, v) in params.items()]
> op.reply.newpart(b'pushkey', mandatoryparams=encodedparams)
> else:
> op.reply.newpart(b'output', data=b'pushback not enabled')
> return result
> _newhandlechangegroup.params = bundle2.handlechangegroup.params
> bundle2.parthandlermapping[b'changegroup'] = _newhandlechangegroup
> EOF
$ cat >> $HGRCPATH <<EOF
> [ui]
> username = nobody <no.reply@example.com>
>
> [alias]
> tglog = log -G -T "{desc} [{phase}:{node|short}]"
> EOF
Set up server repository
$ hg init server
$ cd server
$ echo c0 > f0
$ hg commit -Am 0
adding f0
Set up client repository
$ cd ..
$ hg clone ssh://user@dummy/server client -q
$ cd client
Enable extension
$ cat >> $HGRCPATH <<EOF
> [extensions]
> bundle2=$TESTTMP/bundle2.py
> EOF
Without config
$ cd ../client
$ echo c1 > f1
$ hg commit -Am 1
adding f1
$ hg push
pushing to ssh://user@dummy/server
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
remote: pushback not enabled
$ hg bookmark
no bookmarks set
$ cd ../server
$ hg tglog
o 1 [public:2b9c7234e035]
|
@ 0 [public:6cee5c8f3e5b]
With config
$ cd ../client
$ echo '[experimental]' >> .hg/hgrc
$ echo 'bundle2.pushback = True' >> .hg/hgrc
$ echo c2 > f2
$ hg commit -Am 2
adding f2
$ hg push
pushing to ssh://user@dummy/server
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
$ hg bookmark
new-server-mark 2:0a76dfb2e179
$ cd ../server
$ hg tglog
o 2 [public:0a76dfb2e179]
|
o 1 [public:2b9c7234e035]
|
@ 0 [public:6cee5c8f3e5b]