view tests/test-diff-newlines @ 8742:a964ab624385

merge: allow merging going backwards

New behavior is generally superior and more correct, except possibly
with regards to missing files. hg up . is now effectively a no-op,
which is probably the desired behavior for people expecting to move to
tip, but may surprise people who were expecting deleted files to
reappear.

case 1: update to .

a-w -> a-w

classic: ancestor a
 missing     recreated     right?
 rmed        recreated     WRONG
 added       forgotten     WRONG
 changed     preserved     RIGHT
 conflicted  can't happen

backward merge: ancestor a  (NO EFFECT)
 missing     missing      wrong?
 rm'ed       rm'ed        RIGHT
 added       preserved	  RIGHT
 changed     preserved    RIGHT
 conflicted  can't happen

case 2: update to ancestor of .

a-b-w -> b-w
          \
           a

classic:  ancestor a
 missing       recreated        right?
 rmed          recreated        wrong?
 added         forgotten        wrong?
 changed       preserved        RIGHT
 conflicted    preserved        wrong?

backwards merge: ancestor b
 missing       missing or conflict  right?
 rm'ed         missing or conflict  right?
 changed       preserved            RIGHT
 conflicted    merge                RIGHT
 added         preserved            right?

#!/bin/sh

hg init
python -c 'print "confuse str.splitlines\nembedded\rnewline"' > a
hg ci -Ama -d '1 0'
echo clean diff >> a
hg ci -mb -d '2 0'
hg diff -r0 -r1