$ HGMERGE=true; export HGMERGE

  $ mkdir r1

  $ cd r1

  $ hg init

  $ echo a > a

  $ hg addremove

  adding a

  $ hg commit -m "1" -d "1000000 0"

  $ 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 33aaa84a386b 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" -d "1000000 0"

  $ cd ../r2

  $ hg -q pull ../r1

  $ hg status

  M a

  $ hg parents

  changeset:   0:33aaa84a386b

  user:        test

  date:        Mon Jan 12 13:46:40 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 33aaa84a386b local 33aaa84a386b+ remote 802f095af299

   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@33aaa84a386b+ other a@802f095af299 ancestor a@33aaa84a386b

  updating: b 2/2 files (100.00%)

  getting b

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

  $ hg parents

  changeset:   1:802f095af299

  tag:         tip

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     2

  $ hg --debug up 0

  resolving manifests

   overwrite False partial False

   ancestor 802f095af299 local 802f095af299+ remote 33aaa84a386b

   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@802f095af299+ other a@33aaa84a386b ancestor a@802f095af299

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

  $ hg parents

  changeset:   0:33aaa84a386b

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     1

  $ hg --debug merge || echo failed

  abort: there is nothing to merge - use "hg update" instead

  failed

  $ hg parents

  changeset:   0:33aaa84a386b

  user:        test

  date:        Mon Jan 12 13:46:40 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 33aaa84a386b local 33aaa84a386b+ remote 802f095af299

   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@33aaa84a386b+ other a@802f095af299 ancestor a@33aaa84a386b

  updating: b 2/2 files (100.00%)

  getting b

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

  $ hg parents

  changeset:   1:802f095af299

  tag:         tip

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     2

  $ hg -v history

  changeset:   1:802f095af299

  tag:         tip

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  files:       a b

  description:

  2

  changeset:   0:33aaa84a386b

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  files:       a

  description:

  1

  $ hg diff --nodates

  diff -r 802f095af299 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" -d "1000000 0"

  created new head

  $ cd ../r2

  $ hg -q pull ../r1

  $ hg status

  M a

  $ hg parents

  changeset:   1:802f095af299

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     2

  $ hg --debug up || echo failed

  abort: crosses branches (use 'hg merge' to merge or use 'hg update -C' to discard changes)

  failed

  $ hg --debug merge || echo failed

  abort: outstanding uncommitted changes (use 'hg status' to list changes)

  failed

  $ hg --debug merge -f

    searching for copies back to rev 1

  resolving manifests

   overwrite False partial False

   ancestor 33aaa84a386b local 802f095af299+ remote 030602aee63d

   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@802f095af299+ other a@030602aee63d ancestor a@33aaa84a386b

  updating: b 2/2 files (100.00%)

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

  merging b

  my b@802f095af299+ other b@030602aee63d 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:   1:802f095af299

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     2

  changeset:   2:030602aee63d

  tag:         tip

  parent:      0:33aaa84a386b

  user:        test

  date:        Mon Jan 12 13:46:40 1970 +0000

  summary:     3

  $ hg diff --nodates

  diff -r 802f095af299 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