$ HGMERGE=true; export HGMERGE

  $ hg init basic

  $ cd basic

# should complain

  $ hg backout

  abort: please specify a revision to backout

  $ hg backout -r 0 0

  abort: please specify just one revision

# basic operation

  $ echo a > a

  $ hg commit -d '0 0' -A -m a

  adding a

  $ echo b >> a

  $ hg commit -d '1 0' -m b

  $ hg backout -d '2 0' tip

  reverting a

  changeset 2:2929462c3dff backs out changeset 1:a820f4f40a57

  $ cat a

  a

# file that was removed is recreated

  $ cd ..

  $ hg init remove

  $ cd remove

  $ echo content > a

  $ hg commit -d '0 0' -A -m a

  adding a

  $ hg rm a

  $ hg commit -d '1 0' -m b

  $ hg backout -d '2 0' --merge tip

  adding a

  changeset 2:de31bdc76c0d backs out changeset 1:76862dcce372

  $ cat a

  content

# backout of backout is as if nothing happened

  $ hg backout -d '3 0' --merge tip

  removing a

  changeset 3:7f6d0f120113 backs out changeset 2:de31bdc76c0d

  $ cat a 2>/dev/null || echo cat: a: No such file or directory

  cat: a: No such file or directory

# across branch

  $ cd ..

  $ hg init branch

  $ cd branch

  $ echo a > a

  $ hg ci -Am0

  adding a

  $ echo b > b

  $ hg ci -Am1

  adding b

  $ hg co -C 0

  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

should fail

  $ hg backout 1

  abort: cannot backout change on a different branch

  $ echo c > c

  $ hg ci -Am2

  adding c

  created new head

should fail

  $ hg backout 1

  abort: cannot backout change on a different branch

# 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

  adding 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

  reverting a

  created new head

  changeset 3:26b8ccb9ad91 backs out changeset 1:5a50a024c182

  merging with changeset 3:26b8ccb9ad91

  merging a

  0 files updated, 1 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg commit -d '4 0' -m d

check line 1 is back

  $ cat a

  line 1

  line 2

  line 3

# backout should not back out subsequent changesets

  $ hg init onecs

  $ cd onecs

  $ echo 1 > a

  $ hg commit -d '0 0' -A -m a

  adding a

  $ echo 2 >> a

  $ hg commit -d '1 0' -m b

  $ echo 1 > b

  $ hg commit -d '2 0' -A -m c

  adding b

  $ hg backout -d '3 0' 1

  reverting a

  created new head

  changeset 3:3202beb76721 backs out changeset 1:22bca4c721e5

  the backout changeset is a new head - do not forget to merge

  (use "backout --merge" if you want to auto-merge)

  $ hg locate b

  b

  $ hg update -C tip

  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg locate b

  $ cd ..

  $ hg init m

  $ cd m

  $ echo a > a

  $ hg commit -d '0 0' -A -m a

  adding a

  $ echo b > b

  $ hg commit -d '1 0' -A -m b

  adding b

  $ echo c > c

  $ hg commit -d '2 0' -A -m b

  adding c

  $ hg update 1

  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo d > d

  $ hg commit -d '3 0' -A -m c

  adding d

  created new head

  $ hg merge 2

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg commit -d '4 0' -A -m d

# backout of merge should fail

  $ hg backout 4

  abort: cannot backout a merge changeset without --parent

# backout of merge with bad parent should fail

  $ hg backout --parent 0 4

  abort: cb9a9f314b8b is not a parent of b2f3bb92043e

# backout of non-merge with parent should fail

  $ hg backout --parent 0 3

  abort: cannot use --parent on non-merge changeset

# backout with valid parent should be ok

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

  removing d

  changeset 5:10e5328c8435 backs out changeset 4:b2f3bb92043e

  $ hg rollback

  rolling back to revision 4 (undo commit)

  $ hg update -C

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

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

  removing c

  changeset 5:033590168430 backs out changeset 4:b2f3bb92043e

  $ cd ..

# named branches

  $ hg init named_branches

  $ cd named_branches

  $ echo default > default

  $ hg ci -d '0 0' -Am default

  adding default

  $ hg branch branch1

  marked working directory as branch branch1

  $ echo branch1 > file1

  $ hg ci -d '1 0' -Am file1

  adding file1

  $ hg branch branch2

  marked working directory as branch branch2

  $ echo branch2 > file2

  $ hg ci -d '2 0' -Am file2

  adding file2

  $ hg backout -d '3 0' -r 1 -m 'backout on branch1'

  removing file1

  created new head

  changeset 3:d4e8f6db59fb backs out changeset 1:bf1602f437f3

  the backout changeset is a new head - do not forget to merge

  (use "backout --merge" if you want to auto-merge)

XXX maybe backout shouldn't suggest a merge here as it is a different branch?

on branch2 with branch1 not merged, so file1 should still exist:

  $ hg id

  45bbcd363bf0 (branch2)

  $ hg st -A

  C default

  C file1

  C file2

on branch2 with branch1 merged, so file1 should be gone:

  $ hg merge

  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg ci -d '4 0' -m 'merge backout of branch1'

  $ hg id

  22149cdde76d (branch2) tip

  $ hg st -A

  C default

  C file2

on branch1, so no file1 and file2:

  $ hg co -C branch1

  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg id

  bf1602f437f3 (branch1)

  $ hg st -A

  C default

  C file1

  $ exit 0