tests/test-rename-merge2.t

copies: calculate mergecopies() based on pathcopies()

When copies are stored in changesets, we need a changeset-centric
version of mergecopies() just like we have a changeset-centric version
of pathcopies(). I think the natural way of thinking about
mergecopies() is in terms of pathcopies() from the base to each of the
commits. So if we can rewrite mergecopies() based on two such
pathcopies() calls, we'll get the changeset-centric version for
free. That's what this patch does.

A nice bonus is that it ends up being a lot simpler. mergecopies() has
accumulated a lot of technical debt over time. One good example is the
code for dealing with grafts (the "partial/incomplete/dirty"
stuff). Since pathcopies() already deals with backwards renames and
ping-pong renames, we get that for free.

I've run tests with hard-coded debug logging for "fullcopy" and while
I haven't looked at every difference it produces, all the ones I have
looked at seemed reasonable to me. I'm a little surprised that no more
tests fail when run with '--extra-config-opt
experimental.copies.read-from=compatibility' compared to before this
patch. This patch also fixes the broken cases in test-annotate.t and
test-fastannotate.t. It also enables the part of test-copies.t that
was previously disabled exactly because mergecopies() needed to get a
changeset-centric version.

One drawback of the rewritten code is that we may now make
remotefilelog prefetch more files. We used to prefetch files that were
unique to either side of the merge compared to the other. We now
prefetch files that are unique to either side of the merge compared to
the base. This means that if you added the same file to each side, we
would not prefetch it before, but we would now. Such cases are
probably quite rare, but one likely scenario where they happen is when
moving from a commit to its successor (or the other way around). The
user will probably already have the files in the cache in such cases,
so it's probably not a big deal.

Some timings for calculating mergecopies between two revisions
(revisions shown on each line, all using the common ancestor as base):

In the hg repo:
4.8 4.9: 0.21s -> 0.21s
4.0 4.8: 0.35s -> 0.63s

In and old copy of the mozilla-unified repo:
FIREFOX_BETA_60_BASE^ FIREFOX_BETA_60_BASE: 0.82s -> 0.82s
FIREFOX_NIGHTLY_59_END FIREFOX_BETA_60_BASE: 2.5s -> 2.6s
FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE: 3.9s -> 4.1s
FIREFOX_AURORA_50_BASE FIREFOX_BETA_60_BASE: 31s -> 33s

So it's measurably slower in most cases. The most significant
difference is in the hg repo between revisions 4.0 and 4.8. In that
case it seems to come from the fact that pathcopies() uses
fctx.isintroducedafter() (in _tracefile), while the old mergecopies()
used fctx.linkrev() (in _checkcopies()). That results in a single call
to filectx._adjustlinkrev(), which is responsible for the entire
difference in time (in my repo). So we pay a performance penalty but
we get more correct code (see change in
test-mv-cp-st-diff.t). Deleting the "== f.filenode()" in _tracefile()
recovers the lost performance in the hg repo.

There were are few other optimizations in _checkcopies() that I could
not measure any impact from. One was from the "seen" set. Another was
from a "continue" when the file was not in the destination manifest
(corresponding to "am" in _tracefile).

Also note that merge copies are not calculated when updating with a
clean working copy, which is probably the most common case. I
therefore think the much simpler code is worth the slowdown.

Differential Revision: https://phab.mercurial-scm.org/D6255

  $ mkdir -p t
  $ cd t
  $ cat <<EOF > merge
  > import sys, os
  > f = open(sys.argv[1], "w")
  > 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
  > }
  $ 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
  --------------
    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
   preserving a for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: remote copied from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging a and b to b
  my b@e300d1c794ec+ other b@4ce40f5aca24 ancestor a@924404dff337
   premerge successful
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@e300d1c794ec+ other rev@4ce40f5aca24 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@e300d1c794ec+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving b for resolve of b
   preserving rev for resolve of rev
   a: remote is newer -> g
  getting a
   b: local copied/moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b and a to b
  my b@86a2aa42fc76+ other a@f4db7e329e71 ancestor a@924404dff337
   premerge successful
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@86a2aa42fc76+ other rev@f4db7e329e71 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@86a2aa42fc76+ other rev@f4db7e329e71 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving a for resolve of b
   preserving rev for resolve of rev
  removing a
  starting 4 threads for background file closing (?)
   b: remote moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging a and b to b
  my b@e300d1c794ec+ other b@bdb19105162a ancestor a@924404dff337
   premerge successful
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@e300d1c794ec+ other rev@bdb19105162a ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@e300d1c794ec+ other rev@bdb19105162a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: local copied/moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b and a to b
  my b@02963e448370+ other a@f4db7e329e71 ancestor a@924404dff337
   premerge successful
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@02963e448370+ other rev@f4db7e329e71 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@02963e448370+ other rev@f4db7e329e71 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving rev for resolve of rev
   b: remote created -> g
  getting b
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@94b33a1b7f2d+ other rev@4ce40f5aca24 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@94b33a1b7f2d+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@86a2aa42fc76+ other rev@97c705ade336 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@86a2aa42fc76+ other rev@97c705ade336 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving rev for resolve of rev
   a: other deleted -> r
  removing a
   b: remote created -> g
  getting b
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@94b33a1b7f2d+ other rev@bdb19105162a ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@94b33a1b7f2d+ other rev@bdb19105162a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@02963e448370+ other rev@97c705ade336 ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@02963e448370+ other rev@97c705ade336 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 49b6d8032493
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: both renamed from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@62e7bf090eba+ other b@49b6d8032493 ancestor a@924404dff337
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@62e7bf090eba+ other rev@49b6d8032493 ancestor rev@924404dff337
   b: both renamed from a -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@62e7bf090eba+ other b@49b6d8032493 ancestor a@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@62e7bf090eba+ other rev@49b6d8032493 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
  note: possible conflict - a was renamed multiple times to:
   b
   c
   preserving rev for resolve of rev
   c: remote created -> g
  getting c
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@02963e448370+ other rev@fe905ef2c33e ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@02963e448370+ other rev@fe905ef2c33e ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: af30c7647fc7
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@86a2aa42fc76+ other b@af30c7647fc7 ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@86a2aa42fc76+ other rev@af30c7647fc7 ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@86a2aa42fc76+ other b@af30c7647fc7 ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@86a2aa42fc76+ other rev@af30c7647fc7 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 59318016310c+, remote: bdb19105162a
   preserving b for resolve of b
   preserving rev for resolve of rev
   a: other deleted -> r
  removing a
  starting 4 threads for background file closing (?)
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 8dbce441892a
   preserving b for resolve of b
   preserving rev for resolve of rev
   a: remote is newer -> g
  getting a
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 59318016310c+, remote: bdb19105162a
   preserving b for resolve of b
   preserving rev for resolve of rev
   a: other deleted -> r
  removing a
  starting 4 threads for background file closing (?)
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@59318016310c+ other b@bdb19105162a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@59318016310c+ other rev@bdb19105162a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 8dbce441892a
   preserving b for resolve of b
   preserving rev for resolve of rev
   a: remote is newer -> g
  getting a
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@86a2aa42fc76+ other b@8dbce441892a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@86a2aa42fc76+ other rev@8dbce441892a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 0b76e65c8289+, remote: 4ce40f5aca24
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@0b76e65c8289+ other b@4ce40f5aca24 ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@0b76e65c8289+ other rev@4ce40f5aca24 ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@0b76e65c8289+ other b@4ce40f5aca24 ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@0b76e65c8289+ other rev@4ce40f5aca24 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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: 8dbce441892a
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   a: prompt deleted/changed -> m (premerge)
  picked tool ':prompt' for a (binary False symlink False changedelete True)
  file 'a' was deleted in local [working copy] but was modified in other [merge rev].
  What do you want to do?
  use (c)hanged version, leave (d)eleted, or leave (u)nresolved? u
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@02963e448370+ other b@8dbce441892a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@02963e448370+ other rev@8dbce441892a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@02963e448370+ other b@8dbce441892a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@02963e448370+ other rev@8dbce441892a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  0 files updated, 2 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  --------------
  M a
  M b
  abort: unresolved merge conflicts (see 'hg help resolve')
  --------------
  
  $ 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
  --------------
    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: 0b76e65c8289+, remote: bdb19105162a
   preserving a for resolve of a
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   a: prompt changed/deleted -> m (premerge)
  picked tool ':prompt' for a (binary False symlink False changedelete True)
  file 'a' was deleted in other [merge rev] but was modified in local [working copy].
  What do you want to do?
  use (c)hanged version, (d)elete, or leave (u)nresolved? u
   b: both created -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b
  my b@0b76e65c8289+ other b@bdb19105162a ancestor b@000000000000
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@0b76e65c8289+ other rev@bdb19105162a ancestor rev@924404dff337
   b: both created -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@0b76e65c8289+ other b@bdb19105162a ancestor b@000000000000
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@0b76e65c8289+ other rev@bdb19105162a ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  0 files updated, 2 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  --------------
  M b
  C a
  abort: unresolved merge conflicts (see 'hg help resolve')
  --------------
  
  $ 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
  --------------
    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
   preserving a for resolve of b
   preserving rev for resolve of rev
  removing a
  starting 4 threads for background file closing (?)
   b: remote moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging a and b to b
  my b@e300d1c794ec+ other b@49b6d8032493 ancestor a@924404dff337
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@e300d1c794ec+ other rev@49b6d8032493 ancestor rev@924404dff337
   b: remote moved from a -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@e300d1c794ec+ other b@49b6d8032493 ancestor a@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@e300d1c794ec+ other rev@49b6d8032493 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving b for resolve of b
   preserving rev for resolve of rev
  starting 4 threads for background file closing (?)
   b: local copied/moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b and a to b
  my b@62e7bf090eba+ other a@f4db7e329e71 ancestor a@924404dff337
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@62e7bf090eba+ other rev@f4db7e329e71 ancestor rev@924404dff337
   b: local copied/moved from a -> m (merge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  my b@62e7bf090eba+ other a@f4db7e329e71 ancestor a@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/b* * * (glob)
  merge tool returned: 0
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@62e7bf090eba+ other rev@f4db7e329e71 ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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
  --------------
    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
   preserving b for resolve of b
   preserving rev for resolve of rev
   c: remote created -> g
  getting c
   b: local copied/moved from a -> m (premerge)
  picked tool '* ../merge' for b (binary False symlink False changedelete False) (glob)
  merging b and a to b
  my b@02963e448370+ other a@2b958612230f ancestor a@924404dff337
   premerge successful
   rev: versions differ -> m (premerge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  merging rev
  my rev@02963e448370+ other rev@2b958612230f ancestor rev@924404dff337
   rev: versions differ -> m (merge)
  picked tool '* ../merge' for rev (binary False symlink False changedelete False) (glob)
  my rev@02963e448370+ other rev@2b958612230f ancestor rev@924404dff337
  launching merge tool: * ../merge *$TESTTMP/t/t/rev* * * (glob)
  merge tool returned: 0
  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:

Expected 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 '/^resolving manifests/,$d' 2> /dev/null
    unmatched files in local:
     5/g
     6/g
    unmatched files in other:
     3/g
     4/g
     7/f
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     src: '1/f' -> dst: '1/g' *
     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
  $ 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 ..