tests/notcapable

debugbuilddag: use memctx for speed

This drops the options to run arbitrary shell commands within
commits and the option to create a file that gets appended to
in every revision. It now supports to not write file data at
all, which is very fast for generating a pure 00changelog.i
(useful for discovery tests, for instance).

Timings for 1000 linear nodes:
 * Old `hg debugbuilddag -o '+1000'` took 4.5 secs.
 * New `hg debugbuilddag -o '+1000'` takes 2 secs.
 * New `hg debugbuilddag '+1000'` takes 0.8 secs.

(The last one creates only 00changelog.i).

# Disable the $CAP wire protocol capability.

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

cat > notcapable-$CAP.py << EOF
from mercurial import extensions, repo
def extsetup():
    extensions.wrapfunction(repo.repository, 'capable', wrapper)
def wrapper(orig, self, name, *args, **kwargs):
    if name == '$CAP':
        return False
    return orig(self, name, *args, **kwargs)
EOF

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