tests/notcapable

branchmap: Save changectx creation during update

The newly introduced `branchmap` function allows us to skip the
creation of changectx objects. This speeds up the construction of
the branchmap.

On the mozilla repository (117293 changesets, 15490 mutable)

Before:
  ! impactable 19.9
  ! mutable 0.576
  ! unserved 3.16

After:
  ! impactable 7.03 (2.8x faster)
  ! mutable 0.352 (1.6x)
  ! unserved 1.15 (2.7x)

On the cpython repository (81418 changesets, 6418 mutable)

Before:
  ! impactable 15.9
  ! mutable 0.451
  ! unserved 0.861

After:
  ! impactable 6.55 (2.4x faster)
  ! mutable 0.170 (2.6x faster)
  ! unserved 0.289 (2.9x faster)

On the pypy repository (58852 changesets)

Before:
  ! impactable 13.6

After:
  ! impactable 6.17 (2.2x faster)

On my Mercurial repository (18295 changesets, 2210 mutable)

Before:
  ! impactable 23.9
  ! mutable 0.368
  ! unserved 0.057

After:
  ! impactable 1.31 (18x faster)
  ! mutable 0.042 (8.7x)
  ! unserved 0.025 (2.2x)

# Disable the $CAP wire protocol capability.

if test -z "$CAP"
then
    echo "CAP environment variable not set."
fi

cat > notcapable-$CAP.py << EOF
from mercurial import extensions, peer, localrepo
def extsetup():
    extensions.wrapfunction(peer.peerrepository, 'capable', wrapcapable)
    extensions.wrapfunction(localrepo.localrepository, 'peer', wrappeer)
def wrapcapable(orig, self, name, *args, **kwargs):
    if name in '$CAP'.split(' '):
        return False
    return orig(self, name, *args, **kwargs)
def wrappeer(orig, self):
    # Since we're disabling some newer features, we need to make sure local
    # repos add in the legacy features again.
    return localrepo.locallegacypeer(self)
EOF

echo '[extensions]' >> $HGRCPATH
echo "notcapable-$CAP = `pwd`/notcapable-$CAP.py" >> $HGRCPATH