view tests/test-evolve-content-divergence.t @ 3831:987e335dbe11

evolve: store the obsmarkers to be deleted in evolvestate

Sometimes, we don't create a new node and obsolete one of the old node in favour
of an existing node. When user calls, `hg evolve --abort`, we need to strip that
obsmarker to go back in the same old state. The obsmarker created for new node
are stripped when the new nodes are stripped.

This patch start storing such obsmarkers in the evolvestate so that we can delete
them later if required. Right now we just store successsor and predecessor
information, we might need a better obsmarker serialization techinque in future
to make it more robust.

** Test for handling of content divergent changesets by `hg evolve` **
====================================================================

  $ cat >> $HGRCPATH <<EOF
  > [alias]
  > glog = log -GT "{rev}:{node|short} {desc|firstline}\n ({bookmarks}) [{branch}] {phase}"
  > [extensions]
  > rebase =
  > EOF
  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH

  $ hg init cdiv
  $ cd cdiv
  $ echo ".*\.orig" > .hgignore
  $ hg add .hgignore
  $ hg ci -m "added hgignore"
  $ for ch in a b c d; do echo foo > $ch; hg add $ch; hg ci -qm "added "$ch; done;

  $ hg glog
  @  4:c41c793e0ef1 added d
  |   () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

Creating content-divergence with branch change where base, divergent and other
have different branches
-------------------------------------------------------------------------------

  $ hg branch -r . foobar
  changed branch on 1 changesets

  $ hg up c41c793e0ef1 --hidden
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset c41c793e0ef1
  (hidden revision 'c41c793e0ef1' was rewritten as: 9e5dffcb3d48)
  working directory parent is obsolete! (c41c793e0ef1)
  (use 'hg evolve' to update to its successor: 9e5dffcb3d48)
  $ echo bar > d
  $ hg branch watwat
  marked working directory as branch watwat
  $ hg amend
  2 new content-divergent changesets

  $ hg glog
  @  6:264b04f771fb added d
  |   () [watwat] draft
  | *  5:9e5dffcb3d48 added d
  |/    () [foobar] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent --config ui.interactive=True<<EOF
  > c
  > EOF
  merge:[6] added d
  with: [5] added d
  base: [4] added d
  merging "other" content-divergent changeset '9e5dffcb3d48'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  content divergent changesets on different branches.
  choose branch for the resolution changeset. (a) default or (b) watwat or (c) foobar?  c
  working directory is now at 23a4467c278e

  $ hg glog
  @  7:23a4467c278e added d
  |   () [foobar] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

Testing merging of commit messages
-----------------------------------

When base and one of the divergent has same commit messages and other divergent
has different one

  $ echo wat > d
  $ hg amend

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo bar > d
  $ hg ci -Aqm "added a d with bar in it, expect some beers"

  $ hg prune -r 23a4467c278e -s . --hidden
  1 changesets pruned
  2 new content-divergent changesets

  $ hg glog
  @  9:59081c9c425a added a d with bar in it, expect some beers
  |   () [default] draft
  | *  8:36618f77f252 added d
  |/    () [foobar] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[9] added a d with bar in it, expect some beers
  with: [8] added d
  base: [7] added d
  merging "other" content-divergent changeset '36618f77f252'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory is now at ca80aeaf4ee8

  $ hg glog
  @  10:ca80aeaf4ee8 added a d with bar in it, expect some beers
  |   () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

When base has different message and both divergents has same one

  $ echo foo > d
  $ hg amend -m "foo to d"

  $ hg up ca80aeaf4ee8 --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset ca80aeaf4ee8
  (hidden revision 'ca80aeaf4ee8' was rewritten as: eba0b02801cb)
  working directory parent is obsolete! (ca80aeaf4ee8)
  (use 'hg evolve' to update to its successor: eba0b02801cb)
  $ echo babar > d
  $ hg amend -m "foo to d"
  2 new content-divergent changesets

  $ hg glog
  @  12:0116315a1a4a foo to d
  |   () [default] draft
  | *  11:eba0b02801cb foo to d
  |/    () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[12] foo to d
  with: [11] foo to d
  base: [10] added a d with bar in it, expect some beers
  merging "other" content-divergent changeset 'eba0b02801cb'
  merging d
  warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  abort: fix conflicts and run 'hg evolve --continue' or use 'hg update -C .' to abort
  [255]

  $ echo foobar > d
  $ hg resolve -m
  (no more unresolved files)
  continue: hg evolve --continue
  $ hg evolve --continue
  working directory is now at 3e0a8df515d6

  $ hg glog
  @  13:3e0a8df515d6 foo to d
  |   () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

When all three base, divergent and other has different commit messages creating
conflicts

  $ echo bar > d
  $ hg amend -m "bar to d, expect beers"

  $ hg up 3e0a8df515d6 --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 3e0a8df515d6
  (hidden revision '3e0a8df515d6' was rewritten as: 9ad4721c9004)
  working directory parent is obsolete! (3e0a8df515d6)
  (use 'hg evolve' to update to its successor: 9ad4721c9004)
  $ echo wat > d
  $ hg amend -m "wat to d, wat?"
  2 new content-divergent changesets

  $ hg glog
  @  15:1e834b60df1b wat to d, wat?
  |   () [default] draft
  | *  14:9ad4721c9004 bar to d, expect beers
  |/    () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[15] wat to d, wat?
  with: [14] bar to d, expect beers
  base: [13] foo to d
  merging "other" content-divergent changeset '9ad4721c9004'
  merging d
  warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  abort: fix conflicts and run 'hg evolve --continue' or use 'hg update -C .' to abort
  [255]

  $ echo watbar > d
  $ hg resolve -m
  (no more unresolved files)
  continue: hg evolve --continue

  $ cat > editor.sh <<EOF
  > #!/bin/sh
  > printf "**showing editors text**\n\n"
  > cat \$1
  > printf "\n**done showing editors text**\n\n"
  > cat > \$1 <<ENDOF
  > watbar to d
  > ENDOF
  > EOF

  $ HGEDITOR='sh ./editor.sh' hg evolve --continue
  **showing editors text**
  
  HG: Conflicts while merging changeset description of content-divergent changesets.
  HG: Resolve conflicts in commit messages to continue.
  
  <<<<<<< divergent
  wat to d, wat?||||||| base
  foo to d=======
  bar to d, expect beers>>>>>>> other
  
  **done showing editors text**
  
  working directory is now at 00f8d08aea43

  $ hg glog
  @  16:00f8d08aea43 watbar to d
  |   () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ cd ..

Testing resolution of content-divergent changesets when they are on different
parents and resolution and relocation wont result in conflicts
------------------------------------------------------------------------------

  $ hg init multiparents
  $ cd multiparents
  $ echo ".*\.orig" > .hgignore
  $ hg add .hgignore
  $ hg ci -m "added hgignore"
  $ for ch in a b c d; do echo foo > $ch; hg add $ch; hg ci -qm "added "$ch; done;

  $ hg glog
  @  4:c41c793e0ef1 added d
  |   () [default] draft
  o  3:ca1b80f7960a added c
  |   () [default] draft
  o  2:b1661037fa25 added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg up .^^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo bar > b
  $ hg amend
  2 new orphan changesets

  $ hg rebase -r b1661037fa25 -d 8fa14d15e168 --hidden --config experimental.evolution.allowdivergence=True
  rebasing 2:b1661037fa25 "added b"
  2 new content-divergent changesets

  $ hg glog
  *  6:da4b96f4a8d6 added b
  |   () [default] draft
  | @  5:7ed0642d644b added b
  | |   () [default] draft
  | | *  4:c41c793e0ef1 added d
  | | |   () [default] draft
  | | *  3:ca1b80f7960a added c
  | | |   () [default] draft
  | | x  2:b1661037fa25 added b
  | |/    () [default] draft
  | o  1:c7586e2a9264 added a
  |/    () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[5] added b
  with: [6] added b
  base: [2] added b
  rebasing "other" content-divergent changeset da4b96f4a8d6 on c7586e2a9264
  updating to "local" side of the conflict: 7ed0642d644b
  merging "other" content-divergent changeset '11f849d7159f'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  nothing changed

  $ hg glog
  @  5:7ed0642d644b added b
  |   () [default] draft
  | *  4:c41c793e0ef1 added d
  | |   () [default] draft
  | *  3:ca1b80f7960a added c
  | |   () [default] draft
  | x  2:b1661037fa25 added b
  |/    () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg exp
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 7ed0642d644bb9ad93d252dd9ffe7b4729febe48
  # Parent  c7586e2a92645e473645847a7b69a6dc52be4276
  added b
  
  diff -r c7586e2a9264 -r 7ed0642d644b b
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/b	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +bar

Resolving orphans to get back to a normal graph

  $ hg evolve --all
  move:[3] added c
  atop:[5] added b
  move:[4] added d
  atop:[8] added c
  working directory is now at b6b20b8eefdc
  $ hg glog
  @  9:b6b20b8eefdc added d
  |   () [default] draft
  o  8:7c46f743e62f added c
  |   () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

More testing!

  $ hg up .^^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo x > x
  $ hg ci -Aqm "added x"
  $ hg glog -r .
  @  10:cfae5f87cd34 added x
  |   () [default] draft
  ~

  $ echo foo > x
  $ hg branch bar
  marked working directory as branch bar
  (branches are permanent and global, did you want a bookmark?)
  $ hg amend -m "added foo to x"

  $ hg up cfae5f87cd34 --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset cfae5f87cd34
  (hidden revision 'cfae5f87cd34' was rewritten as: 580d9d182d90)
  working directory parent is obsolete! (cfae5f87cd34)
  (use 'hg evolve' to update to its successor: 580d9d182d90)
  $ hg rebase -r . -d b6b20b8eefdc --config experimental.evolution.allowdivergence=True
  rebasing 10:cfae5f87cd34 "added x"
  2 new content-divergent changesets

  $ hg glog
  @  12:c4d1990428e3 added x
  |   () [default] draft
  | *  11:580d9d182d90 added foo to x
  | |   () [bar] draft
  o |  9:b6b20b8eefdc added d
  | |   () [default] draft
  o |  8:7c46f743e62f added c
  |/    () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[12] added x
  with: [11] added foo to x
  base: [10] added x
  rebasing "other" content-divergent changeset 580d9d182d90 on b6b20b8eefdc
  updating to "local" side of the conflict: c4d1990428e3
  merging "other" content-divergent changeset 'd3bfc0b3f350'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory is now at be41fdcd0ee1

  $ hg exp
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Branch bar
  # Node ID be41fdcd0ee181081c4e42c6ee333d3dc3b3ab45
  # Parent  b6b20b8eefdce1f32126c71d20bdb72a62b38268
  added foo to x
  
  diff -r b6b20b8eefdc -r be41fdcd0ee1 x
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/x	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

The above `hg exp` and the following log call demonstrates that message, content
and branch change is preserved in case of relocation
  $ hg glog
  @  14:be41fdcd0ee1 added foo to x
  |   () [bar] draft
  o  9:b6b20b8eefdc added d
  |   () [default] draft
  o  8:7c46f743e62f added c
  |   () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

Testing when both the content-divergence are on different parents and resolution
will lead to conflicts
---------------------------------------------------------------------------------

  $ hg up .^^^
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved

  $ echo y > y
  $ hg ci -Aqm "added y"
  $ hg glog -r .
  @  15:9c30046901ab added y
  |   () [default] draft
  ~

  $ echo bar > y
  $ hg amend

  $ hg up 9c30046901ab --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 9c30046901ab
  (hidden revision '9c30046901ab' was rewritten as: 29e08829c51f)
  working directory parent is obsolete! (9c30046901ab)
  (use 'hg evolve' to update to its successor: 29e08829c51f)
  $ hg rebase -r . -d be41fdcd0ee1 --config experimental.evolution.allowdivergence=True
  rebasing 15:9c30046901ab "added y"
  2 new content-divergent changesets
  $ echo wat > y
  $ hg amend

  $ hg glog
  @  18:4065e1d314c3 added y
  |   () [bar] draft
  | *  16:29e08829c51f added y
  | |   () [default] draft
  o |  14:be41fdcd0ee1 added foo to x
  | |   () [bar] draft
  o |  9:b6b20b8eefdc added d
  | |   () [default] draft
  o |  8:7c46f743e62f added c
  |/    () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[18] added y
  with: [16] added y
  base: [15] added y
  rebasing "other" content-divergent changeset 29e08829c51f on be41fdcd0ee1
  updating to "local" side of the conflict: 4065e1d314c3
  merging "other" content-divergent changeset '6d515d1ffc69'
  merging y
  warning: conflicts while merging y! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  abort: fix conflicts and run 'hg evolve --continue' or use 'hg update -C .' to abort
  [255]

  $ echo watbar > y
  $ hg resolve -m
  (no more unresolved files)
  continue: hg evolve --continue
  $ hg evolve --continue
  working directory is now at bbaca013758a

  $ hg glog
  @  20:bbaca013758a added y
  |   () [bar] draft
  o  14:be41fdcd0ee1 added foo to x
  |   () [bar] draft
  o  9:b6b20b8eefdc added d
  |   () [default] draft
  o  8:7c46f743e62f added c
  |   () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg obslog -r . --all
  @    bbaca013758a (20) added y
  |\
  x |  4065e1d314c3 (18) added y
  | |    rewritten(content) as bbaca013758a using amend by test (Thu Jan 01 00:00:00 1970 +0000)
  | |
  | x  6d515d1ffc69 (19) added y
  | |    rewritten(branch, content) as bbaca013758a using evolve by test (Thu Jan 01 00:00:00 1970 +0000)
  | |
  | x  29e08829c51f (16) added y
  | |    rewritten(parent) as 6d515d1ffc69 using evolve by test (Thu Jan 01 00:00:00 1970 +0000)
  | |
  x |  f1d75198aac4 (17) added y
  |/     rewritten(content) as 4065e1d314c3 using amend by test (Thu Jan 01 00:00:00 1970 +0000)
  |
  x  9c30046901ab (15) added y
       rewritten(content) as 29e08829c51f using amend by test (Thu Jan 01 00:00:00 1970 +0000)
       rewritten(branch, parent) as f1d75198aac4 using rebase by test (Thu Jan 01 00:00:00 1970 +0000)
  

checking that relocated commit is there
  $ hg exp 6d515d1ffc69 --hidden
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 6d515d1ffc6925b036c933078ccb804c26da80b2
  # Parent  be41fdcd0ee181081c4e42c6ee333d3dc3b3ab45
  added y
  
  diff -r be41fdcd0ee1 -r 6d515d1ffc69 y
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/y	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +bar

Testing when the relocation will result in conflicts and merging wont
----------------------------------------------------------------------

  $ hg glog
  @  20:bbaca013758a added y
  |   () [bar] draft
  o  14:be41fdcd0ee1 added foo to x
  |   () [bar] draft
  o  9:b6b20b8eefdc added d
  |   () [default] draft
  o  8:7c46f743e62f added c
  |   () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg up .^^^^
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved

  $ echo z > z
  $ hg ci -Aqm "added z"
  $ hg glog -r .
  @  21:884c9d1a1a84 added z
  |   () [default] draft
  ~

  $ echo foo > y
  $ hg add y
  $ hg amend

  $ hg up 884c9d1a1a84 --hidden
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  updated to hidden changeset 884c9d1a1a84
  (hidden revision '884c9d1a1a84' was rewritten as: 3e22a949fe7d)
  working directory parent is obsolete! (884c9d1a1a84)
  (use 'hg evolve' to update to its successor: 3e22a949fe7d)
  $ hg rebase -r . -d bbaca013758a --config experimental.evolution.allowdivergence=True
  rebasing 21:884c9d1a1a84 "added z"
  2 new content-divergent changesets
  $ echo bar > z
  $ hg amend

  $ hg glog
  @  24:d2eca78cc588 added z
  |   () [bar] draft
  | *  22:3e22a949fe7d added z
  | |   () [default] draft
  o |  20:bbaca013758a added y
  | |   () [bar] draft
  o |  14:be41fdcd0ee1 added foo to x
  | |   () [bar] draft
  o |  9:b6b20b8eefdc added d
  | |   () [default] draft
  o |  8:7c46f743e62f added c
  |/    () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

  $ hg evolve --content-divergent
  merge:[24] added z
  with: [22] added z
  base: [21] added z
  rebasing "other" content-divergent changeset 3e22a949fe7d on bbaca013758a
  merging y
  warning: conflicts while merging y! (edit, then use 'hg resolve --mark')
  abort: unresolved merge conflicts (see hg help resolve)
  [255]

  $ hg diff
  diff -r bbaca013758a y
  --- a/y	Thu Jan 01 00:00:00 1970 +0000
  +++ b/y	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,5 @@
  +<<<<<<< destination: bbaca013758a bar - test: added y
   watbar
  +=======
  +foo
  +>>>>>>> evolving:    3e22a949fe7d - test: added z
  diff -r bbaca013758a z
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/z	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +z

  $ echo foo > y
  $ hg resolve -m
  (no more unresolved files)
  continue: hg evolve --continue

  $ hg evolve --continue
  working directory is now at a15eb4e32166

  $ hg glog
  @  25:a15eb4e32166 added z
  |   () [default] draft
  o  20:bbaca013758a added y
  |   () [bar] draft
  o  14:be41fdcd0ee1 added foo to x
  |   () [bar] draft
  o  9:b6b20b8eefdc added d
  |   () [default] draft
  o  8:7c46f743e62f added c
  |   () [default] draft
  o  5:7ed0642d644b added b
  |   () [default] draft
  o  1:c7586e2a9264 added a
  |   () [default] draft
  o  0:8fa14d15e168 added hgignore
      () [default] draft

XXX: z should have bar inside, the merge definitely did not happen
  $ hg exp
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID a15eb4e32166b0652fdec4c1dd30c9d668323bac
  # Parent  bbaca013758a55364955939e2d2e4536cb8d05cf
  added z
  
  diff -r bbaca013758a -r a15eb4e32166 y
  --- a/y	Thu Jan 01 00:00:00 1970 +0000
  +++ b/y	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,1 @@
  -watbar
  +foo
  diff -r bbaca013758a -r a15eb4e32166 z
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/z	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +z