$ HGMERGE=true; export HGMERGE

  $ hg init r1

  $ cd r1

  $ echo a > a

  $ hg addremove

  adding a

  $ hg commit -m "1"

  $ hg clone . ../r2

  updating to branch default

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

  $ cd ../r2

  $ hg up

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

  $ echo abc > a

  $ hg diff --nodates

  diff -r c19d34741b0a a

  --- a/a

  +++ b/a

  @@ -1,1 +1,1 @@

  -a

  +abc

  $ cd ../r1

  $ echo b > b

  $ echo a2 > a

  $ hg addremove

  adding b

  $ hg commit -m "2"

  $ cd ../r2

  $ hg -q pull ../r1

  $ hg status

  M a

  $ hg parents

  changeset:   0:c19d34741b0a

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     1

  $ hg --debug up

    searching for copies back to rev 1

    unmatched files in other:

     b

  resolving manifests

   overwrite False partial False

   ancestor c19d34741b0a local c19d34741b0a+ remote 1e71731e6fbb

   a: versions differ -> m

   b: remote created -> g

  preserving a for resolve of a

  updating: a 1/2 files (50.00%)

  picked tool 'true' for a (binary False symlink False)

  merging a

  my a@c19d34741b0a+ other a@1e71731e6fbb ancestor a@c19d34741b0a

  updating: b 2/2 files (100.00%)

  getting b

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

  $ hg parents

  changeset:   1:1e71731e6fbb

  tag:         tip

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     2

  $ hg --debug up 0

  resolving manifests

   overwrite False partial False

   ancestor 1e71731e6fbb local 1e71731e6fbb+ remote c19d34741b0a

   a: versions differ -> m

   b: other deleted -> r

  preserving a for resolve of a

  updating: b 1/2 files (50.00%)

  removing b

  updating: a 2/2 files (100.00%)

  picked tool 'true' for a (binary False symlink False)

  merging a

  my a@1e71731e6fbb+ other a@c19d34741b0a ancestor a@1e71731e6fbb

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

  $ hg parents

  changeset:   0:c19d34741b0a

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     1

  $ hg --debug merge

  [255]

  $ hg parents

  changeset:   0:c19d34741b0a

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     1

  $ hg --debug up

    searching for copies back to rev 1

    unmatched files in other:

     b

  resolving manifests

   overwrite False partial False

   ancestor c19d34741b0a local c19d34741b0a+ remote 1e71731e6fbb

   a: versions differ -> m

   b: remote created -> g

  preserving a for resolve of a

  updating: a 1/2 files (50.00%)

  picked tool 'true' for a (binary False symlink False)

  merging a

  my a@c19d34741b0a+ other a@1e71731e6fbb ancestor a@c19d34741b0a

  updating: b 2/2 files (100.00%)

  getting b

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

  $ hg parents

  changeset:   1:1e71731e6fbb

  tag:         tip

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     2

  $ hg -v history

  changeset:   1:1e71731e6fbb

  tag:         tip

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  files:       a b

  description:

  2

  changeset:   0:c19d34741b0a

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  files:       a

  description:

  1

  $ hg diff --nodates

  diff -r 1e71731e6fbb a

  --- a/a

  +++ b/a

  @@ -1,1 +1,1 @@

  -a2

  +abc

create a second head

  $ cd ../r1

  $ hg up 0

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

  $ echo b2 > b

  $ echo a3 > a

  $ hg addremove

  adding b

  $ hg commit -m "3"

  created new head

  $ cd ../r2

  $ hg -q pull ../r1

  $ hg status

  M a

  $ hg parents

  changeset:   1:1e71731e6fbb

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     2

  $ hg --debug up

  abort: crosses branches (merge branches or use --clean to discard changes)

  [255]

  $ hg --debug merge

  [255]

  $ hg --debug merge -f

    searching for copies back to rev 1

  resolving manifests

   overwrite False partial False

   ancestor c19d34741b0a local 1e71731e6fbb+ remote 83c51d0caff4

   a: versions differ -> m

   b: versions differ -> m

  preserving a for resolve of a

  preserving b for resolve of b

  updating: a 1/2 files (50.00%)

  picked tool 'true' for a (binary False symlink False)

  merging a

  my a@1e71731e6fbb+ other a@83c51d0caff4 ancestor a@c19d34741b0a

  updating: b 2/2 files (100.00%)

  picked tool 'true' for b (binary False symlink False)

  merging b

  my b@1e71731e6fbb+ other b@83c51d0caff4 ancestor b@000000000000

  0 files updated, 2 files merged, 0 files removed, 0 files unresolved

  (branch merge, don't forget to commit)

  $ hg parents

  changeset:   1:1e71731e6fbb

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     2

  changeset:   2:83c51d0caff4

  tag:         tip

  parent:      0:c19d34741b0a

  user:        test

  date:        Thu Jan 01 00:00:00 1970 +0000

  summary:     3

  $ hg diff --nodates

  diff -r 1e71731e6fbb a

  --- a/a

  +++ b/a

  @@ -1,1 +1,1 @@

  -a2

  +abc

test a local add

  $ cd ..

  $ hg init a

  $ hg init b

  $ echo a > a/a

  $ echo a > b/a

  $ hg --cwd a commit -A -m a

  adding a

  $ cd b

  $ hg add a

  $ hg pull -u ../a

  pulling from ../a

  requesting all changes

  adding changesets

  adding manifests

  adding file changes

  added 1 changesets with 1 changes to 1 files

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

  $ hg st