tests/test-backout

Reverse the way backout is doing the merge

Currently, backout is creating a backout revision as a child node of the
backed out node and will leave you at this new head. This has several
drawbacks:
* this changes the current head
* when there is a long history between the backed out node and the
current head, this will generate a huge number of diffs that are scary
at first sight, and not very natural to review before commit.
The change consists to switch back to the original node as soon as the
backout node (which becomes the new tip) has been created. Then the
--merge option can just merge this new tip in the current node.
* the current head/node is not changed from the user's point of view
* even without using the --merge option, the backout revision is still
easy to locate, as this is the tip
* the merge is much more intuitive as diffs of the merge is right you
are looking to backout

#!/bin/sh

HGMERGE=true; export HGMERGE

hg init basic
cd basic

echo '# should complain'
hg backout
hg backout -r 0 0

echo '# basic operation'
echo a > a
hg commit -d '0 0' -A -m a
echo b >> a
hg commit -d '1 0' -m b

hg backout -d '2 0' tip
cat a

echo '# file that was removed is recreated'
cd ..
hg init remove
cd remove

echo content > a
hg commit -d '0 0' -A -m a

hg rm a
hg commit -d '1 0' -m b

hg backout -d '2 0' --merge tip
cat a

echo '# backout of backout is as if nothing happened'

hg backout -d '3 0' --merge tip
cat a 2>/dev/null || echo cat: a: No such file or directory

echo '# across branch'
cd ..
hg init branch
cd branch
echo a > a
hg ci -Am0 -d '0 0'
echo b > b
hg ci -Am1 -d '0 0'
hg co -C 0
# should fail
hg backout -d '0 0' 1
echo c > c
hg ci -Am2 -d '0 0'
# should fail
hg backout -d '0 0' 1

echo '# backout with merge'
cd ..
hg init merge
cd merge

echo line 1 > a
echo line 2 >> a
hg commit -d '0 0' -A -m a
# remove line 1
echo line 2 > a
hg commit -d '1 0' -m b

echo line 3 >> a
hg commit -d '2 0' -m c

hg backout --merge -d '3 0' 1
hg commit -d '4 0' -m d
# check line 1 is back
cat a

echo '# backout should not back out subsequent changesets'
hg init onecs
cd onecs
echo 1 > a
hg commit -d '0 0' -A -m a
echo 2 >> a
hg commit -d '1 0' -m b
echo 1 > b
hg commit -d '2 0' -A -m c
hg backout -d '3 0' 1
hg locate b
hg update -C tip
hg locate b

cd ..
hg init m
cd m
echo a > a
hg commit -d '0 0' -A -m a
echo b > b
hg commit -d '1 0' -A -m b
echo c > c
hg commit -d '2 0' -A -m b
hg update 1
echo d > d
hg commit -d '3 0' -A -m c
hg merge 2
hg commit -d '4 0' -A -m d

echo '# backout of merge should fail'

hg backout 4

echo '# backout of merge with bad parent should fail'

hg backout --parent 0 4

echo '# backout of non-merge with parent should fail'

hg backout --parent 0 3

echo '# backout with valid parent should be ok'

hg backout -d '5 0' --parent 2 4

hg rollback
hg update -C

hg backout -d '6 0' --parent 3 4

exit 0