view tests/notcapable @ 25996:b12e00a05d57 stable

revset: prevent crash caused by empty group expression while optimizing "or"

An empty group expression "()" generates None in AST, so it should be tested
before destructuring a tuple.

"A | ()" is still evaluated to an error because I'm not sure whether "()"
represents an empty set or an empty expression (= a unit value). They are
identical in "or" operation, but they should be evaluated differently in
"and" operation.

  expression  empty set  unit value
  ----------  ---------  ----------
  ()          {}         A
  A & ()      {}         A
  A | ()      A          A

# 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