view tests/test-merge-tools.t @ 25757:4d1382fd96ff

context: write dirstate out explicitly at the end of markcommitted

To detect change of a file without redundant comparison of file
content, dirstate recognizes a file as certainly clean, if:

  (1) it is already known as "normal",
  (2) dirstate entry for it has valid (= not "-1") timestamp, and
  (3) mode, size and timestamp of it on the filesystem are as same as
      ones expected in dirstate

This works as expected in many cases, but doesn't in the corner case
that changing a file keeps mode, size and timestamp of it on the
filesystem.

The timetable below shows steps in one of typical such situations:

  ---- ----------------------------------- ----------------
                                           timestamp of "f"
                                           ----------------
                                           dirstate   file-
  time          action                     mem  file  system
  ---- ----------------------------------- ---- ----- -----
   *                                             ***    ***
       - 'hg transplant REV1 REV2 ...'
         - transplanting REV1
           ....
   N
           - change "f", but keep size                   N
             (via 'patch.patch()')
           - 'dirstate.normal("f")'          N   ***
             (via 'repo.commit()')

         - transplanting REV2
           - change "f", but keep size                   N
             (via 'patch.patch()')
           - aborted while patching
  N+1
         - release wlock
           - 'dirstate.write()'              N    N      N

       - 'hg status' shows "r1" as "clean"   N    N      N
  ---- ----------------------------------- ---- ----- -----

The most important point is that 'dirstate.write()' is executed at N+1
or later. This causes writing dirstate timestamp N of "f" out
successfully. If it is executed at N, 'parsers.pack_dirstate()'
replaces timestamp N with "-1" before actual writing dirstate out.

This issue can occur when 'hg transplant' satisfies conditions below:

  - multiple revisions to be transplanted change the same file
  - those revisions don't change mode and size of the file, and
  - the 2nd or later revision of them fails after changing the file

The root cause of this issue is that files are changed without
flushing in-memory dirstate changes via 'repo.commit()' (even though
omitting 'dirstate.normallookup()' on files changed by 'patch.patch()'
for efficiency also causes this issue).

To detect changes of files correctly, this patch writes in-memory
dirstate changes out explicitly after marking files as clean in
'committablectx.markcommitted()', which is invoked via
'repo.commit()'.

After this change, timetable is changed as below:

  ---- ----------------------------------- ----------------
                                           timestamp of "f"
                                           ----------------
                                           dirstate   file-
  time          action                     mem  file  system
  ---- ----------------------------------- ---- ----- -----
   *                                             ***    ***
       - 'hg transplant REV1 REV2 ...'
         - transplanting REV1
           ....
   N
           - change "f", but keep size                   N
             (via 'patch.patch()')
           - 'dirstate.normal("f")'          N    ***
             (via 'repo.commit()')
       ----------------------------------- ---- ----- -----
           - 'dirsttate.write()'            -1    -1
       ----------------------------------- ---- ----- -----
         - transplanting REV2
           - change "f", but keep size                   N
             (via 'patch.patch()')
           - aborted while patching
  N+1
         - release wlock
           - 'dirstate.write()'              -1   -1     N

       - 'hg status' shows "r1" as "clean"   -1   -1     N
  ---- ----------------------------------- ---- ----- -----

To reproduce this issue in tests certainly, this patch emulates some
timing critical actions as below:

  - change "f" at N

    'patch.patch()' with 'fakepatchtime.py' explicitly changes mtime
    of patched files to "2000-01-01 00:00" (= N).

  - 'dirstate.write()' via 'repo.commit()' at N

    'fakedirstatewritetime.py' forces 'pack_dirstate()' to use
    "2000-01-01 00:00" as "now", only if 'pack_dirstate()' is invoked
    via 'committablectx.markcommitted()'.

  - 'dirstate.write()' via releasing wlock at N+1 (or "not at N")

    'pack_dirstate()' via releasing wlock uses actual timestamp at
    runtime as "now", and it should be different from the "2000-01-01
    00:00" of "f".

BTW, this patch doesn't test cases below, even though 'patch.patch()'
is used similarly in these cases:

  1. failure of 'hg import' or 'hg qpush'

  2. success of 'hg import', 'hg qpush' or 'hg transplant'

Case (1) above doesn't cause this kind of issue, because:

  - if patching is aborted by conflicts, changed files are committed

    changed files are marked as CLEAN, even though they are partially
    patched.

  - otherwise, dirstate are fully restored by 'dirstateguard'

    For example in timetable above, timestamp of "f" in .hg/dirstate
    is restored to -1 (or less than N), and subsequent 'hg status' can
    detect changes correctly.

Case (2) always causes 'repo.status()' invocation via 'repo.commit()'
just after changing files inside same wlock scope.

  ---- ----------------------------------- ----------------
                                           timestamp of "f"
                                           ----------------
                                           dirstate   file-
  time          action                     mem  file  system
  ---- ----------------------------------- ---- ----- -----
  N                                              ***   ***
       - make file "f" clean                            N

       - execute 'hg foobar'
         ....
         - 'dirstate.normal("f")'           N    ***
           (e.g. via dirty check
            or previous 'repo.commit()')

         - change "f", but keep size                    N
         - 'repo.status()' (*1)
           (via 'repo.commit()')
  ---- ----------------------------------- ---- ----- -----

At a glance, 'repo.status()' at (*1) seems to cause similar issue (=
"changed files are treated as clean"), but actually doesn't.

'dirstate._lastnormaltime' should be N at (*1) above, because
'dirstate.normal()' via dirty check is finished at N.

Therefore, "f" changed at N (= 'dirstate._lastnormaltime') is forcibly
treated as "unsure" at (*1), and changes are detected as expected (see
'dirstate.status()' for detail).

If 'hg import' is executed with '--no-commit', 'repo.status()' isn't
invoked just after changing files inside same wlock scope.

But preceding 'dirstate.normal()' is invoked inside another wlock
scope via 'cmdutil.bailifchanged()', and in-memory changes should be
flushed at the end of that scope.

Therefore, timestamp N of clean "f" should be replaced by -1, if
'dirstate.write()' is invoked at N. It means that condition of this
issue isn't satisfied.

test merge-tools configuration - mostly exercising filemerge.py

  $ unset HGMERGE # make sure HGMERGE doesn't interfere with the test
  $ hg init

revision 0

  $ echo "revision 0" > f
  $ echo "space" >> f
  $ hg commit -Am "revision 0"
  adding f

revision 1

  $ echo "revision 1" > f
  $ echo "space" >> f
  $ hg commit -Am "revision 1"
  $ hg update 0 > /dev/null

revision 2

  $ echo "revision 2" > f
  $ echo "space" >> f
  $ hg commit -Am "revision 2"
  created new head
  $ hg update 0 > /dev/null

revision 3 - simple to merge

  $ echo "revision 3" >> f
  $ hg commit -Am "revision 3"
  created new head

revision 4 - hard to merge

  $ hg update 0 > /dev/null
  $ echo "revision 4" > f
  $ hg commit -Am "revision 4"
  created new head

  $ echo "[merge-tools]" > .hg/hgrc

  $ beforemerge() {
  >   cat .hg/hgrc
  >   echo "# hg update -C 1"
  >   hg update -C 1 > /dev/null
  > }
  $ aftermerge() {
  >   echo "# cat f"
  >   cat f
  >   echo "# hg stat"
  >   hg stat
  >   rm -f f.orig
  > }

Tool selection

default is internal merge:

  $ beforemerge
  [merge-tools]
  # hg update -C 1

hg merge -r 2
override $PATH to ensure hgmerge not visible; use $PYTHON in case we're
running from a devel copy, not a temp installation

  $ PATH="$BINDIR" $PYTHON "$BINDIR"/hg merge -r 2
  merging f
  warning: conflicts during merge.
  merging f incomplete! (edit conflicts, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  <<<<<<< local: ef83787e2614  - test: revision 1
  revision 1
  =======
  revision 2
  >>>>>>> other: 0185f4e0cf02  - test: revision 2
  space
  # hg stat
  M f
  ? f.orig

simplest hgrc using false for merge:

  $ echo "false.whatever=" >> .hg/hgrc
  $ beforemerge
  [merge-tools]
  false.whatever=
  # hg update -C 1
  $ hg merge -r 2
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

#if unix-permissions

unexecutable file in $PATH shouldn't be found:

  $ echo "echo fail" > false
  $ hg up -qC 1
  $ PATH="`pwd`:$BINDIR" $PYTHON "$BINDIR"/hg merge -r 2
  merging f
  warning: conflicts during merge.
  merging f incomplete! (edit conflicts, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ rm false

#endif

executable directory in $PATH shouldn't be found:

  $ mkdir false
  $ hg up -qC 1
  $ PATH="`pwd`:$BINDIR" $PYTHON "$BINDIR"/hg merge -r 2
  merging f
  warning: conflicts during merge.
  merging f incomplete! (edit conflicts, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ rmdir false

true with higher .priority gets precedence:

  $ echo "true.priority=1" >> .hg/hgrc
  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  # hg update -C 1
  $ hg merge -r 2
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

unless lowered on command line:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.priority=-7
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

or false set higher on command line:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.false.priority=117
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

or true.executable not found in PATH:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=nonexistentmergetool
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

or true.executable with bogus path:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=/nonexistent/mergetool
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

but true.executable set to cat found in PATH works:

  $ echo "true.executable=cat" >> .hg/hgrc
  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2
  merging f
  revision 1
  space
  revision 0
  space
  revision 2
  space
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

and true.executable set to cat with path works:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=cat
  merging f
  revision 1
  space
  revision 0
  space
  revision 2
  space
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

#if unix-permissions

environment variables in true.executable are handled:

  $ echo 'echo "custom merge tool"' > .hg/merge.sh
  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg --config merge-tools.true.executable='sh' \
  >    --config merge-tools.true.args=.hg/merge.sh \
  >    merge -r 2
  merging f
  custom merge tool
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

#endif

Tool selection and merge-patterns

merge-patterns specifies new tool false:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-patterns.f=false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

merge-patterns specifies executable not found in PATH and gets warning:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-patterns.f=true --config merge-tools.true.executable=nonexistentmergetool
  couldn't find merge tool true specified for f
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

merge-patterns specifies executable with bogus path and gets warning:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-patterns.f=true --config merge-tools.true.executable=/nonexistent/mergetool
  couldn't find merge tool true specified for f
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

ui.merge overrules priority

ui.merge specifies false:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

ui.merge specifies internal:fail:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:fail
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

ui.merge specifies :local (without internal prefix):

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=:local
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

ui.merge specifies internal:other:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:other
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 2
  space
  # hg stat
  M f

ui.merge specifies internal:prompt:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:prompt
   no tool found to merge f
  keep (l)ocal or take (o)ther? l
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

ui.merge specifies internal:dump:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:dump
  merging f
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.base
  ? f.local
  ? f.orig
  ? f.other

f.base:

  $ cat f.base
  revision 0
  space

f.local:

  $ cat f.local
  revision 1
  space

f.other:

  $ cat f.other
  revision 2
  space
  $ rm f.base f.local f.other

ui.merge specifies internal:other but is overruled by pattern for false:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:other --config merge-patterns.f=false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

Premerge

ui.merge specifies internal:other but is overruled by --tool=false

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config ui.merge=internal:other --tool=false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

HGMERGE specifies internal:other but is overruled by --tool=false

  $ HGMERGE=internal:other ; export HGMERGE
  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --tool=false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

  $ unset HGMERGE # make sure HGMERGE doesn't interfere with remaining tests

update is a merge ...

(this also tests that files reverted with '--rev REV' are treated as
"modified", even if none of mode, size and timestamp of them isn't
changed on the filesystem (see also issue4583))

  $ cat >> $HGRCPATH <<EOF
  > [fakedirstatewritetime]
  > # emulate invoking dirstate.write() via repo.status()
  > # at 2000-01-01 00:00
  > fakenow = 200001010000
  > EOF

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg update -q 0
  $ f -s f
  f: size=17
  $ touch -t 200001010000 f
  $ hg debugrebuildstate
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
  > EOF
  $ hg revert -q -r 1 .
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > fakedirstatewritetime = !
  > EOF
  $ f -s f
  f: size=17
  $ touch -t 200001010000 f
  $ hg status f
  M f
  $ hg update -r 2
  merging f
  revision 1
  space
  revision 0
  space
  revision 2
  space
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

update should also have --tool

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg update -q 0
  $ f -s f
  f: size=17
  $ touch -t 200001010000 f
  $ hg debugrebuildstate
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
  > EOF
  $ hg revert -q -r 1 .
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > fakedirstatewritetime = !
  > EOF
  $ f -s f
  f: size=17
  $ touch -t 200001010000 f
  $ hg status f
  M f
  $ hg update -r 2 --tool false
  merging f
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

Default is silent simplemerge:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 3
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  revision 3
  # hg stat
  M f

.premerge=True is same:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 3 --config merge-tools.true.premerge=True
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  revision 3
  # hg stat
  M f

.premerge=False executes merge-tool:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 3 --config merge-tools.true.premerge=False
  merging f
  revision 1
  space
  revision 0
  space
  revision 0
  space
  revision 3
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

premerge=keep keeps conflict markers in:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 4 --config merge-tools.true.premerge=keep
  merging f
  <<<<<<< local: ef83787e2614  - test: revision 1
  revision 1
  space
  =======
  revision 4
  >>>>>>> other: 81448d39c9a0 - test: revision 4
  revision 0
  space
  revision 4
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  <<<<<<< local: ef83787e2614  - test: revision 1
  revision 1
  space
  =======
  revision 4
  >>>>>>> other: 81448d39c9a0 - test: revision 4
  # hg stat
  M f

premerge=keep-merge3 keeps conflict markers with base content:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 4 --config merge-tools.true.premerge=keep-merge3
  merging f
  <<<<<<< local: ef83787e2614  - test: revision 1
  revision 1
  space
  ||||||| base
  revision 0
  space
  =======
  revision 4
  >>>>>>> other: 81448d39c9a0 - test: revision 4
  revision 0
  space
  revision 4
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  <<<<<<< local: ef83787e2614  - test: revision 1
  revision 1
  space
  ||||||| base
  revision 0
  space
  =======
  revision 4
  >>>>>>> other: 81448d39c9a0 - test: revision 4
  # hg stat
  M f


Tool execution

set tools.args explicit to include $base $local $other $output:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=head --config merge-tools.true.args='$base $local $other $output' \
  >   | sed 's,==> .* <==,==> ... <==,g'
  merging f
  ==> ... <==
  revision 0
  space
  
  ==> ... <==
  revision 1
  space
  
  ==> ... <==
  revision 2
  space
  
  ==> ... <==
  revision 1
  space
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f

Merge with "echo mergeresult > $local":

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=echo --config merge-tools.true.args='mergeresult > $local'
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  mergeresult
  # hg stat
  M f

- and $local is the file f:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=echo --config merge-tools.true.args='mergeresult > f'
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  mergeresult
  # hg stat
  M f

Merge with "echo mergeresult > $output" - the variable is a bit magic:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -r 2 --config merge-tools.true.executable=echo --config merge-tools.true.args='mergeresult > $output'
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ aftermerge
  # cat f
  mergeresult
  # hg stat
  M f

Merge using tool with a path that must be quoted:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ cat <<EOF > 'my merge tool'
  > cat "\$1" "\$2" "\$3" > "\$4"
  > EOF
  $ hg --config merge-tools.true.executable='sh' \
  >    --config merge-tools.true.args='"./my merge tool" $base $local $other $output' \
  >    merge -r 2
  merging f
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ rm -f 'my merge tool'
  $ aftermerge
  # cat f
  revision 0
  space
  revision 1
  space
  revision 2
  space
  # hg stat
  M f

Issue3581: Merging a filename that needs to be quoted
(This test doesn't work on Windows filesystems even on Linux, so check
for Unix-like permission)

#if unix-permissions
  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ echo "revision 5" > '"; exit 1; echo "'
  $ hg commit -Am "revision 5"
  adding "; exit 1; echo "
  warning: filename contains '"', which is reserved on Windows: '"; exit 1; echo "'
  $ hg update -C 1 > /dev/null
  $ echo "revision 6" > '"; exit 1; echo "'
  $ hg commit -Am "revision 6"
  adding "; exit 1; echo "
  warning: filename contains '"', which is reserved on Windows: '"; exit 1; echo "'
  created new head
  $ hg merge --config merge-tools.true.executable="true" -r 5
  merging "; exit 1; echo "
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg update -C 1 > /dev/null
#endif

Merge post-processing

cat is a bad merge-tool and doesn't change:

  $ beforemerge
  [merge-tools]
  false.whatever=
  true.priority=1
  true.executable=cat
  # hg update -C 1
  $ hg merge -y -r 2 --config merge-tools.true.checkchanged=1
  merging f
  revision 1
  space
  revision 0
  space
  revision 2
  space
   output file f appears unchanged
  was merge successful (yn)? n
  merging f failed!
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ aftermerge
  # cat f
  revision 1
  space
  # hg stat
  M f
  ? f.orig

#if symlink

internal merge cannot handle symlinks and shouldn't try:

  $ hg update -q -C 1
  $ rm f
  $ ln -s symlink f
  $ hg commit -qm 'f is symlink'
  $ hg merge -r 2 --tool internal:merge
  merging f
  warning: internal :merge cannot merge symlinks for f
  merging f incomplete! (edit conflicts, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

#endif