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
hg init a
cd a
echo 'root' >root
hg add root
hg commit -d '0 0' -u test -m "Adding root node"
hg heads
echo '-------'
hg heads .
echo '======='
echo 'a' >a
hg add a
hg branch a
hg commit -d '1 0' -u test -m "Adding a branch"
hg heads
echo '-------'
hg heads .
echo '======='
hg update -C 0
echo 'b' >b
hg add b
hg branch b
hg commit -d '2 0' -u test -m "Adding b branch"
hg heads
echo '-------'
hg heads .
echo '======='
echo 'bh1' >bh1
hg add bh1
hg commit -d '3 0' -u test -m "Adding b branch head 1"
hg heads
echo '-------'
hg heads .
echo '======='
hg update -C 2
echo 'bh2' >bh2
hg add bh2
hg commit -d '4 0' -u test -m "Adding b branch head 2"
hg heads
echo '-------'
hg heads .
echo '======='
hg update -C 2
echo 'bh3' >bh3
hg add bh3
hg commit -d '5 0' -u test -m "Adding b branch head 3"
hg heads
echo '-------'
hg heads .
echo '======='
hg merge 4
hg commit -d '6 0' -u test -m "Merging b branch head 2 and b branch head 3"
hg heads
echo '-------'
hg heads .
echo '======='
echo 'c' >c
hg add c
hg branch c
hg commit -d '7 0' -u test -m "Adding c branch"
hg heads
echo '-------'
hg heads .
echo '======='
hg heads -r 3 .
echo $?
echo '-------'
hg heads -r 2 .
echo $?
echo '-------'
hg update -C 4
echo $?
echo '-------'
hg heads -r 3 .
echo $?
echo '-------'
hg heads -r 2 .
echo $?
echo '-------'
hg heads -r 7 .
echo $?
echo '======='
for i in 0 1 2 3 4 5 6 7; do
hg update -C "$i"
hg heads
echo '-------'
hg heads .
echo '-------'
done
echo '======='
for i in a b c z; do
hg heads "$i"
echo '-------'
done
echo '======='
hg heads 0 1 2 3 4 5 6 7