view tests/test-rename-merge2.t @ 20742:3681de20b0a7

parsers: fail fast if Python has wrong minor version (issue4110)

This change causes an informative ImportError to be raised when importing
the parsers extension module if the minor version of the currently-running
Python interpreter doesn't match that of the Python used when compiling
the extension module.

This change also exposes a parsers.versionerrortext constant in the
C implementation of the module.  Its presence can be used to determine
whether this behavior is present in a version of the module.  The value
of the constant is the leading text of the ImportError raised and is set
to "Python minor version mismatch".

Here is an example of what the new error looks like:

  Traceback (most recent call last):
    File "test.py", line 1, in <module>
      import mercurial.parsers
  ImportError: Python minor version mismatch: The Mercurial extension
  modules were compiled with Python 2.7.6, but Mercurial is currently using
  Python with sys.hexversion=33883888: Python 2.5.6
  (r256:88840, Nov 18 2012, 05:37:10)
  [GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))]
   at: /opt/local/Library/Frameworks/Python.framework/Versions/2.5/Resources/
    Python.app/Contents/MacOS/Python

The reason for raising an error in this scenario is that Python's C API
is known not to be compatible from minor version to minor version, even
if sys.api_version is the same.  See for example this Python bug report
about incompatibilities between 2.5 and 2.6+:

  http://bugs.python.org/issue8118

These incompatibilities can cause Mercurial to break in mysterious,
unforeseen ways.  For example, when Mercurial compiled with Python 2.7 was
run with 2.5, the following crash occurred when running "hg status":

  http://bz.selenic.com/show_bug.cgi?id=4110

After this crash was fixed, running with Python 2.5 no longer crashes, but
the following puzzling behavior still occurs:

    $ hg status
      ...
      File ".../mercurial/changelog.py", line 123, in __init__
        revlog.revlog.__init__(self, opener, "00changelog.i")
      File ".../mercurial/revlog.py", line 251, in __init__
        d = self._io.parseindex(i, self._inline)
      File ".../mercurial/revlog.py", line 158, in parseindex
        index, cache = parsers.parse_index2(data, inline)
    TypeError: data is not a string

which can be reproduced more simply with:

    import mercurial.parsers as parsers
    parsers.parse_index2("", True)

Both the crash and the TypeError occurred because the Python C API's
PyString_Check() returns the wrong value when the C header files from
Python 2.7 are run with Python 2.5.  This is an example of an
incompatibility of the sort mentioned in the Python bug report above.

Failing fast with an informative error message results in a better user
experience in cases like the above.  The information in the ImportError
also simplifies troubleshooting for those on Mercurial mailing lists, the
bug tracker, etc.

This patch only adds the version check to parsers.c, which is sufficient
to affect command-line commands like "hg status" and "hg summary".
An idea for a future improvement is to move the version-checking C code
to a more central location, and have it run when importing all
Mercurial extension modules and not just parsers.c.

  $ mkdir -p t
  $ cd t
  $ cat <<EOF > merge
  > import sys, os
  > f = open(sys.argv[1], "wb")
  > f.write("merge %s %s %s" % (sys.argv[1], sys.argv[2], sys.argv[3]))
  > f.close()
  > EOF

perform a test merge with possible renaming
args:
$1 = action in local branch
$2 = action in remote branch
$3 = action in working dir
$4 = expected result

  $ tm()
  > {
  >     hg init t
  >     cd t
  >     echo "[merge]" >> .hg/hgrc
  >     echo "followcopies = 1" >> .hg/hgrc
  > 
  >     # base
  >     echo base > a
  >     echo base > rev # used to force commits
  >     hg add a rev
  >     hg ci -m "base"
  > 
  >     # remote
  >     echo remote > rev
  >     if [ "$2" != "" ] ; then $2 ; fi
  >     hg ci -m "remote"
  > 
  >     # local
  >     hg co -q 0
  >     echo local > rev
  >     if [ "$1" != "" ] ; then $1 ; fi
  >     hg ci -m "local"
  > 
  >     # working dir
  >     echo local > rev
  >     if [ "$3" != "" ] ; then $3 ; fi
  > 
  >     # merge
  >     echo "--------------"
  >     echo "test L:$1 R:$2 W:$3 - $4"
  >     echo "--------------"
  >     hg merge -y --debug --traceback --tool="python ../merge"
  > 
  >     echo "--------------"
  >     hg status -camC -X rev
  > 
  >     hg ci -m "merge"
  > 
  >     echo "--------------"
  >     echo
  > 
  >     cd ..
  >     rm -r t
  > }
  $ up() {
  >     cp rev $1
  >     hg add $1 2> /dev/null
  >     if [ "$2" != "" ] ; then
  >         cp rev $2
  >         hg add $2 2> /dev/null
  >     fi
  > }
  $ uc() { up $1; hg cp $1 $2; } # update + copy
  $ um() { up $1; hg mv $1 $2; }
  $ nc() { hg cp $1 $2; } # just copy
  $ nm() { hg mv $1 $2; } # just move
  $ tm "up a  " "nc a b" "      " "1  get local a to b"
  created new head
  --------------
  test L:up a   R:nc a b W:       - 1  get local a to b
  --------------
    searching for copies back to rev 1
    unmatched files in other:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: e300d1c794ec+, remote: 4ce40f5aca24
   a: remote copied to b -> m
    preserving a for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: a 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging a and b to b
  my b@e300d1c794ec+ other b@4ce40f5aca24 ancestor a@924404dff337
   premerge successful
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@e300d1c794ec+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  C a
  --------------
  
  $ tm "nc a b" "up a  " "      " "2  get rem change to a and b"
  created new head
  --------------
  test L:nc a b R:up a   W:       - 2  get rem change to a and b
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 86a2aa42fc76+, remote: f4db7e329e71
   a: remote is newer -> g
   b: local copied/moved to a -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b and a to b
  my b@86a2aa42fc76+ other a@f4db7e329e71 ancestor a@924404dff337
   premerge successful
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@86a2aa42fc76+ other rev@f4db7e329e71 ancestor rev@924404dff337
  1 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M a
  M b
    a
  --------------
  
  $ tm "up a  " "nm a b" "      " "3  get local a change to b, remove a"
  created new head
  --------------
  test L:up a   R:nm a b W:       - 3  get local a change to b, remove a
  --------------
    searching for copies back to rev 1
    unmatched files in other:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: e300d1c794ec+, remote: bdb19105162a
   a: remote moved to b -> m
    preserving a for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  removing a
  updating: a 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging a and b to b
  my b@e300d1c794ec+ other b@bdb19105162a ancestor a@924404dff337
   premerge successful
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@e300d1c794ec+ other rev@bdb19105162a ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  --------------
  
  $ tm "nm a b" "up a  " "      " "4  get remote change to b"
  created new head
  --------------
  test L:nm a b R:up a   W:       - 4  get remote change to b
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 02963e448370+, remote: f4db7e329e71
   b: local copied/moved to a -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: b 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b and a to b
  my b@02963e448370+ other a@f4db7e329e71 ancestor a@924404dff337
   premerge successful
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@02963e448370+ other rev@f4db7e329e71 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  --------------
  
  $ tm "      " "nc a b" "      " "5  get b"
  created new head
  --------------
  test L:       R:nc a b W:       - 5  get b
  --------------
    searching for copies back to rev 1
    unmatched files in other:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' 
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 94b33a1b7f2d+, remote: 4ce40f5aca24
   b: remote created -> g
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting b
  updating: b 1/2 files (50.00%)
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@94b33a1b7f2d+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  C a
  --------------
  
  $ tm "nc a b" "      " "      " "6  nothing"
  created new head
  --------------
  test L:nc a b R:       W:       - 6  nothing
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' 
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 86a2aa42fc76+, remote: 97c705ade336
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: rev 1/1 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@86a2aa42fc76+ other rev@97c705ade336 ancestor rev@924404dff337
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  C a
  C b
  --------------
  
  $ tm "      " "nm a b" "      " "7  get b"
  created new head
  --------------
  test L:       R:nm a b W:       - 7  get b
  --------------
    searching for copies back to rev 1
    unmatched files in other:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' 
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 94b33a1b7f2d+, remote: bdb19105162a
   a: other deleted -> r
   b: remote created -> g
   rev: versions differ -> m
    preserving rev for resolve of rev
  removing a
  updating: a 1/3 files (33.33%)
  getting b
  updating: b 2/3 files (66.67%)
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@94b33a1b7f2d+ other rev@bdb19105162a ancestor rev@924404dff337
  1 files updated, 1 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  --------------
  
  $ tm "nm a b" "      " "      " "8  nothing"
  created new head
  --------------
  test L:nm a b R:       W:       - 8  nothing
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' 
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 02963e448370+, remote: 97c705ade336
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: rev 1/1 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@02963e448370+ other rev@97c705ade336 ancestor rev@924404dff337
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  C b
  --------------
  
  $ tm "um a b" "um a b" "      " "9  do merge with ancestor in a"
  created new head
  --------------
  test L:um a b R:um a b W:       - 9  do merge with ancestor in a
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 62e7bf090eba+, remote: 49b6d8032493
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: b 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@62e7bf090eba+ other b@49b6d8032493 ancestor a@924404dff337
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@62e7bf090eba+ other rev@49b6d8032493 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  --------------
  

m "um a c" "um x c" "      " "10 do merge with no ancestor"

  $ tm "nm a b" "nm a c" "      " "11 get c, keep b"
  created new head
  --------------
  test L:nm a b R:nm a c W:       - 11 get c, keep b
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    unmatched files in other:
     c
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' !
     src: 'a' -> dst: 'c' !
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 02963e448370+, remote: fe905ef2c33e
   a: divergent renames -> dr
   c: remote created -> g
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting c
  updating: c 1/3 files (33.33%)
  updating: a 2/3 files (66.67%)
  note: possible conflict - a was renamed multiple times to:
   b
   c
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@02963e448370+ other rev@fe905ef2c33e ancestor rev@924404dff337
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M c
  C b
  --------------
  
  $ tm "nc a b" "up b  " "      " "12 merge b no ancestor"
  created new head
  --------------
  test L:nc a b R:up b   W:       - 12 merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 86a2aa42fc76+, remote: af30c7647fc7
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: b 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@86a2aa42fc76+ other b@af30c7647fc7 ancestor b@000000000000
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@86a2aa42fc76+ other rev@af30c7647fc7 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  C a
  --------------
  
  $ tm "up b  " "nm a b" "      " "13 merge b no ancestor"
  created new head
  --------------
  test L:up b   R:nm a b W:       - 13 merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 59318016310c+, remote: bdb19105162a
   a: other deleted -> r
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  removing a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
  0 files updated, 2 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  --------------
  
  $ tm "nc a b" "up a b" "      " "14 merge b no ancestor"
  created new head
  --------------
  test L:nc a b R:up a b W:       - 14 merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 86a2aa42fc76+, remote: 8dbce441892a
   a: remote is newer -> g
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
  1 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M a
  M b
  --------------
  
  $ tm "up b  " "nm a b" "      " "15 merge b no ancestor, remove a"
  created new head
  --------------
  test L:up b   R:nm a b W:       - 15 merge b no ancestor, remove a
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 59318016310c+, remote: bdb19105162a
   a: other deleted -> r
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  removing a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
  0 files updated, 2 files merged, 1 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  --------------
  
  $ tm "nc a b" "up a b" "      " "16 get a, merge b no ancestor"
  created new head
  --------------
  test L:nc a b R:up a b W:       - 16 get a, merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 86a2aa42fc76+, remote: 8dbce441892a
   a: remote is newer -> g
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
  1 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M a
  M b
  --------------
  
  $ tm "up a b" "nc a b" "      " "17 keep a, merge b no ancestor"
  created new head
  --------------
  test L:up a b R:nc a b W:       - 17 keep a, merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 0b76e65c8289+, remote: 4ce40f5aca24
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: b 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@0b76e65c8289+ other b@4ce40f5aca24 ancestor b@000000000000
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@0b76e65c8289+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  C a
  --------------
  
  $ tm "nm a b" "up a b" "      " "18 merge b no ancestor"
  created new head
  --------------
  test L:nm a b R:up a b W:       - 18 merge b no ancestor
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 02963e448370+, remote: 8dbce441892a
  remote changed a which local deleted
  use (c)hanged version or leave (d)eleted? c
   a: prompt recreating -> g
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting a
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@02963e448370+ other b@8dbce441892a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@02963e448370+ other rev@8dbce441892a ancestor rev@924404dff337
  1 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M a
  M b
  --------------
  
  $ tm "up a b" "nm a b" "      " "19 merge b no ancestor, prompt remove a"
  created new head
  --------------
  test L:up a b R:nm a b W:       - 19 merge b no ancestor, prompt remove a
  --------------
    searching for copies back to rev 1
    unmatched files new in both:
     b
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 0b76e65c8289+, remote: bdb19105162a
  local changed a which remote deleted
  use (c)hanged version or (d)elete? c
   a: prompt keep -> a
   b: versions differ -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: a 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b
  my b@0b76e65c8289+ other b@bdb19105162a ancestor b@000000000000
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@0b76e65c8289+ other rev@bdb19105162a ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
  C a
  --------------
  
  $ tm "up a  " "um a b" "      " "20 merge a and b to b, remove a"
  created new head
  --------------
  test L:up a   R:um a b W:       - 20 merge a and b to b, remove a
  --------------
    searching for copies back to rev 1
    unmatched files in other:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: e300d1c794ec+, remote: 49b6d8032493
   a: remote moved to b -> m
    preserving a for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  removing a
  updating: a 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging a and b to b
  my b@e300d1c794ec+ other b@49b6d8032493 ancestor a@924404dff337
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@e300d1c794ec+ other rev@49b6d8032493 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  --------------
  
  $ tm "um a b" "up a  " "      " "21 merge a and b to b"
  created new head
  --------------
  test L:um a b R:up a   W:       - 21 merge a and b to b
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 62e7bf090eba+, remote: f4db7e329e71
   b: local copied/moved to a -> m
    preserving b for resolve of b
   rev: versions differ -> m
    preserving rev for resolve of rev
  updating: b 1/2 files (50.00%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b and a to b
  my b@62e7bf090eba+ other a@f4db7e329e71 ancestor a@924404dff337
  updating: rev 2/2 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@62e7bf090eba+ other rev@f4db7e329e71 ancestor rev@924404dff337
  0 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  --------------
  

m "nm a b" "um x a" "      " "22 get a, keep b"

  $ tm "nm a b" "up a c" "      " "23 get c, keep b"
  created new head
  --------------
  test L:nm a b R:up a c W:       - 23 get c, keep b
  --------------
    searching for copies back to rev 1
    unmatched files in local:
     b
    unmatched files in other:
     c
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: 'a' -> dst: 'b' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: 924404dff337, local: 02963e448370+, remote: 2b958612230f
   b: local copied/moved to a -> m
    preserving b for resolve of b
   c: remote created -> g
   rev: versions differ -> m
    preserving rev for resolve of rev
  getting c
  updating: c 1/3 files (33.33%)
  updating: b 2/3 files (66.67%)
  picked tool 'python ../merge' for b (binary False symlink False)
  merging b and a to b
  my b@02963e448370+ other a@2b958612230f ancestor a@924404dff337
   premerge successful
  updating: rev 3/3 files (100.00%)
  picked tool 'python ../merge' for rev (binary False symlink False)
  merging rev
  my rev@02963e448370+ other rev@2b958612230f ancestor rev@924404dff337
  1 files updated, 2 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  --------------
  M b
    a
  M c
  --------------
  

  $ cd ..


Systematic and terse testing of merge merges and ancestor calculation:

Excpected result:

\  a  m1  m2  dst
0  -   f   f   f   "versions differ"
1  f   g   g   g   "versions differ"
2  f   f   f   f   "versions differ"
3  f   f   g  f+g  "remote copied to " + f
4  f   f   g   g   "remote moved to " + f
5  f   g   f  f+g  "local copied to " + f2
6  f   g   f   g   "local moved to " + f2
7  -  (f)  f   f   "remote differs from untracked local"
8  f  (f)  f   f   "remote differs from untracked local"

  $ hg init ancestortest
  $ cd ancestortest
  $ for x in 1 2 3 4 5 6 8; do mkdir $x; echo a > $x/f; done
  $ hg ci -Aqm "a"
  $ mkdir 0
  $ touch 0/f
  $ hg mv 1/f 1/g
  $ hg cp 5/f 5/g
  $ hg mv 6/f 6/g
  $ hg rm 8/f
  $ for x in */*; do echo m1 > $x; done
  $ hg ci -Aqm "m1"
  $ hg up -qr0
  $ mkdir 0 7
  $ touch 0/f 7/f
  $ hg mv 1/f 1/g
  $ hg cp 3/f 3/g
  $ hg mv 4/f 4/g
  $ for x in */*; do echo m2 > $x; done
  $ hg ci -Aqm "m2"
  $ hg up -qr1
  $ mkdir 7 8
  $ echo m > 7/f
  $ echo m > 8/f
  $ hg merge -f --tool internal:dump -v --debug -r2 | sed '/^updating:/,$d' 2> /dev/null
    searching for copies back to rev 1
    unmatched files in local:
     5/g
     6/g
    unmatched files in other:
     3/g
     4/g
     7/f
    unmatched files new in both:
     0/f
     1/g
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: '3/f' -> dst: '3/g' *
     src: '4/f' -> dst: '4/g' *
     src: '5/f' -> dst: '5/g' *
     src: '6/f' -> dst: '6/g' *
    checking for directory renames
  resolving manifests
   branchmerge: True, force: True, partial: False
   ancestor: e6cb3cf11019, local: ec44bf929ab5+, remote: c62e34d0b898
  remote changed 8/f which local deleted
  use (c)hanged version or leave (d)eleted? c
   0/f: versions differ -> m
    preserving 0/f for resolve of 0/f
   1/g: versions differ -> m
    preserving 1/g for resolve of 1/g
   2/f: versions differ -> m
    preserving 2/f for resolve of 2/f
   3/f: versions differ -> m
    preserving 3/f for resolve of 3/f
   3/f: remote copied to 3/g -> m
    preserving 3/f for resolve of 3/g
   4/f: remote moved to 4/g -> m
    preserving 4/f for resolve of 4/g
   5/f: versions differ -> m
    preserving 5/f for resolve of 5/f
   5/g: local copied/moved to 5/f -> m
    preserving 5/g for resolve of 5/g
   6/g: local copied/moved to 6/f -> m
    preserving 6/g for resolve of 6/g
   7/f: remote differs from untracked local -> m
    preserving 7/f for resolve of 7/f
   8/f: prompt recreating -> g
  removing 4/f
  getting 8/f
  $ hg mani
  0/f
  1/g
  2/f
  3/f
  4/f
  5/f
  5/g
  6/g
  $ for f in */*; do echo $f:; cat $f; done
  0/f:
  m1
  0/f.base:
  0/f.local:
  m1
  0/f.orig:
  m1
  0/f.other:
  m2
  1/g:
  m1
  1/g.base:
  a
  1/g.local:
  m1
  1/g.orig:
  m1
  1/g.other:
  m2
  2/f:
  m1
  2/f.base:
  a
  2/f.local:
  m1
  2/f.orig:
  m1
  2/f.other:
  m2
  3/f:
  m1
  3/f.base:
  a
  3/f.local:
  m1
  3/f.orig:
  m1
  3/f.other:
  m2
  3/g:
  m1
  3/g.base:
  a
  3/g.local:
  m1
  3/g.orig:
  m1
  3/g.other:
  m2
  4/g:
  m1
  4/g.base:
  a
  4/g.local:
  m1
  4/g.orig:
  m1
  4/g.other:
  m2
  5/f:
  m1
  5/f.base:
  a
  5/f.local:
  m1
  5/f.orig:
  m1
  5/f.other:
  m2
  5/g:
  m1
  5/g.base:
  a
  5/g.local:
  m1
  5/g.orig:
  m1
  5/g.other:
  m2
  6/g:
  m1
  6/g.base:
  a
  6/g.local:
  m1
  6/g.orig:
  m1
  6/g.other:
  m2
  7/f:
  m
  7/f.base:
  7/f.local:
  m
  7/f.orig:
  m
  7/f.other:
  m2
  8/f:
  m2
  $ cd ..