make mq play nicely with the branch cache - if no patches are applied, don't do anything different - if the cache includes valid data from one of the patch revisions, use the cache, but don't save anything new - if the cache has data from before the patch revisions only, save what the list of branches would be without the patch revisions

#!/bin/sh

hg init
echo "nothing" > a
hg add a
hg commit -m ancestor -d "1000000 0"
echo "something" > a
hg commit -m branch1 -d "1000000 0"
hg co 0
echo "something else" > a
hg commit -m branch2 -d "1000000 0"
HGMERGE=merge; export HGMERGE
hg merge 1
hg id
egrep -v ">>>|<<<" a
hg status