Correct optimization from 3464f5e77f34; add a test.
If there are two (or more) heads that point to the same .hgtags
node, we can safely skip parsing the file in all but the last head.
(In 3464f5e77f34, we were parsing the file in the first head and
skipping all the others.)
#!/bin/sh
echo "[extensions]" >> $HGRCPATH
echo "mq=" >> $HGRCPATH
hg init
hg qinit
echo x > x
hg ci -Ama
hg qnew a.patch
echo a > a
hg add a
hg qrefresh
hg qnew b.patch
echo b > b
hg add b
hg qrefresh
hg qnew c.patch
echo c > c
hg add c
hg qrefresh
hg qpop -a
echo % should fail
hg qguard +fail
hg qpush
echo % should guard a.patch
hg qguard +a
echo % should print +a
hg qguard
hg qpop
hg qguard a.patch
echo % should push b.patch
hg qpush
hg qpop
hg qselect a
echo % should push a.patch
hg qpush
hg qguard c.patch -a
echo % should print -a
hg qguard c.patch
echo % should skip c.patch
hg qpush -a
hg qguard -n c.patch
echo % should push c.patch
hg qpush -a
hg qpop -a
hg qselect -n
echo % should push all
hg qpush -a
hg qpop -a
hg qguard a.patch +1
hg qguard b.patch +2
hg qselect 1
echo % should push a.patch, not b.patch
hg qpush
hg qpush
hg qpop -a
hg qselect 2
echo % should push b.patch
hg qpush
hg qpop -a
hg qselect 1 2
echo % should push a.patch, b.patch
hg qpush
hg qpush
hg qpop -a
hg qguard a.patch +1 +2 -3
hg qselect 1 2 3
echo % list patches and guards
hg qguard -l
echo % list series
hg qseries -v
echo % list guards
hg qselect
echo % should push b.patch
hg qpush
hg qpush -a
hg qselect -n --reapply
echo % guards in series file: +1 +2 -3
hg qselect -s
echo % should show c.patch
hg qapplied