Store empty (default) branch in branch cache, too.
Operations on this branch don't work otherwise.
Reading branches.cache had to be adjusted to allow an empty label.
Adjusted reading of the cache tip for symmetry, no functional change here.
#!/bin/sh
hg init
echo a > a
hg add a
hg commit -m "1" -d "1000000 0"
hg status
hg copy a b
hg status
hg --debug commit -m "2" -d "1000000 0"
echo "we should see two history entries"
hg history -v
echo "we should see one log entry for a"
hg log a
echo "this should show a revision linked to changeset 0"
hg debugindex .hg/store/data/a.i
echo "we should see one log entry for b"
hg log b
echo "this should show a revision linked to changeset 1"
hg debugindex .hg/store/data/b.i
echo "this should show the rename information in the metadata"
hg debugdata .hg/store/data/b.d 0 | head -3 | tail -2
$TESTDIR/md5sum.py .hg/store/data/b.i
hg cat b > bsum
$TESTDIR/md5sum.py bsum
hg cat a > asum
$TESTDIR/md5sum.py asum
hg verify