merge: do early copy to deal with issue636
Without copies/renames, merges source names are 1:1 with their
targets. Copies and renames introduce the possibility that there will
be two merges with the same input but different output. By doing the
copy to the destination name before the merge, the actual merge
becomes 1:1 again, and no source is the input to two different merges.
- add a preliminary scan to applyupdates to do copies
- for the merge action, pass the old name (for finding ancestors) and
the new name (for input to the merge) to filemerge
- eliminate the old post-merge copy
- lookup file contents from new name in filemerge
- pass new name to external merge helper
- report merge failure at new name
- add a test
#!/bin/sh
#
# Corrupt an hg repo with two pulls.
#
# create one repo with a long history
hg init source1
cd source1
touch foo
hg add foo
for i in 1 2 3 4 5 6 7 8 9 10; do
echo $i >> foo
hg ci -m $i
done
cd ..
# create one repo with a shorter history
hg clone -r 0 source1 source2
cd source2
echo a >> foo
hg ci -m a
cd ..
# create a third repo to pull both other repos into it
hg init corrupted
cd corrupted
# use a hook to make the second pull start while the first one is still running
echo '[hooks]' >> .hg/hgrc
echo 'prechangegroup = sleep 5' >> .hg/hgrc
# start a pull...
hg pull ../source1 &
# ... and start another pull before the first one has finished
sleep 1
hg pull ../source2 2>/dev/null
# see the result
wait
hg verify