view tests/test-contrib.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.

Set vars:

  $ CONTRIBDIR="$TESTDIR/../contrib"

Prepare repo-a:

  $ hg init repo-a
  $ cd repo-a

  $ echo this is file a > a
  $ hg add a
  $ hg commit -m first

  $ echo adding to file a >> a
  $ hg commit -m second

  $ echo adding more to file a >> a
  $ hg commit -m third

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions

Dumping revlog of file a to stdout:

  $ python "$CONTRIBDIR/dumprevlog" .hg/store/data/a.i
  file: .hg/store/data/a.i
  node: 183d2312b35066fb6b3b449b84efc370d50993d0
  linkrev: 0
  parents: 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
  length: 15
  -start-
  this is file a
  
  -end-
  node: b1047953b6e6b633c0d8197eaa5116fbdfd3095b
  linkrev: 1
  parents: 183d2312b35066fb6b3b449b84efc370d50993d0 0000000000000000000000000000000000000000
  length: 32
  -start-
  this is file a
  adding to file a
  
  -end-
  node: 8c4fd1f7129b8cdec6c7f58bf48fb5237a4030c1
  linkrev: 2
  parents: b1047953b6e6b633c0d8197eaa5116fbdfd3095b 0000000000000000000000000000000000000000
  length: 54
  -start-
  this is file a
  adding to file a
  adding more to file a
  
  -end-

Dump all revlogs to file repo.dump:

  $ find .hg/store -name "*.i" | sort | xargs python "$CONTRIBDIR/dumprevlog" > ../repo.dump
  $ cd ..

Undumping into repo-b:

  $ hg init repo-b
  $ cd repo-b
  $ python "$CONTRIBDIR/undumprevlog" < ../repo.dump
  .hg/store/00changelog.i
  .hg/store/00manifest.i
  .hg/store/data/a.i
  $ cd ..

Rebuild fncache with clone --pull:

  $ hg clone --pull -U repo-b repo-c
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files

Verify:

  $ hg -R repo-c verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions

Compare repos:

  $ hg -R repo-c incoming repo-a
  comparing with repo-a
  searching for changes
  no changes found
  [1]

  $ hg -R repo-a incoming repo-c
  comparing with repo-c
  searching for changes
  no changes found
  [1]

Test simplemerge command:

  $ cp "$CONTRIBDIR/simplemerge" .
  $ echo base > base
  $ echo local > local
  $ cat base >> local
  $ cp local orig
  $ cat base > other
  $ echo other >> other

changing local directly

  $ python simplemerge local base other && echo "merge succeeded"
  merge succeeded
  $ cat local
  local
  base
  other
  $ cp orig local

printing to stdout

  $ python simplemerge -p local base other
  local
  base
  other

local:

  $ cat local
  local
  base

conflicts

  $ cp base conflict-local
  $ cp other conflict-other
  $ echo not other >> conflict-local
  $ echo end >> conflict-local
  $ echo end >> conflict-other

  $ python simplemerge -p conflict-local base conflict-other
  base
  <<<<<<< conflict-local
  not other
  end
  =======
  other
  end
  >>>>>>> conflict-other
  warning: conflicts during merge.
  [1]

1 label

  $ python simplemerge -p -L foo conflict-local base conflict-other
  base
  <<<<<<< foo
  not other
  end
  =======
  other
  end
  >>>>>>> conflict-other
  warning: conflicts during merge.
  [1]

2 labels

  $ python simplemerge -p -L foo -L bar conflict-local base conflict-other
  base
  <<<<<<< foo
  not other
  end
  =======
  other
  end
  >>>>>>> bar
  warning: conflicts during merge.
  [1]

3 labels

  $ python simplemerge -p -L foo -L bar -L base conflict-local base conflict-other
  base
  <<<<<<< foo
  not other
  end
  ||||||| base
  =======
  other
  end
  >>>>>>> bar
  warning: conflicts during merge.
  [1]

too many labels

  $ python simplemerge -p -L foo -L bar -L baz -L buz conflict-local base conflict-other
  abort: can only specify three labels.
  [255]

binary file

  $ $PYTHON -c "f = file('binary-local', 'w'); f.write('\x00'); f.close()"
  $ cat orig >> binary-local
  $ python simplemerge -p binary-local base other
  warning: binary-local looks like a binary file.
  [1]

binary file --text

  $ python simplemerge -a -p binary-local base other 2>&1
  warning: binary-local looks like a binary file.
  \x00local (esc)
  base
  other

help

  $ python simplemerge --help
  simplemerge [OPTS] LOCAL BASE OTHER
  
      Simple three-way file merge utility with a minimal feature set.
  
      Apply to LOCAL the changes necessary to go from BASE to OTHER.
  
      By default, LOCAL is overwritten with the results of this operation.
  
  options:
   -L --label       labels to use on conflict markers
   -a --text        treat all files as text
   -p --print       print results instead of overwriting LOCAL
      --no-minimal  no effect (DEPRECATED)
   -h --help        display help and exit
   -q --quiet       suppress output

wrong number of arguments

  $ python simplemerge
  simplemerge: wrong number of arguments
  simplemerge [OPTS] LOCAL BASE OTHER
  
      Simple three-way file merge utility with a minimal feature set.
  
      Apply to LOCAL the changes necessary to go from BASE to OTHER.
  
      By default, LOCAL is overwritten with the results of this operation.
  
  options:
   -L --label       labels to use on conflict markers
   -a --text        treat all files as text
   -p --print       print results instead of overwriting LOCAL
      --no-minimal  no effect (DEPRECATED)
   -h --help        display help and exit
   -q --quiet       suppress output
  [1]

bad option

  $ python simplemerge --foo -p local base other
  simplemerge: option --foo not recognized
  simplemerge [OPTS] LOCAL BASE OTHER
  
      Simple three-way file merge utility with a minimal feature set.
  
      Apply to LOCAL the changes necessary to go from BASE to OTHER.
  
      By default, LOCAL is overwritten with the results of this operation.
  
  options:
   -L --label       labels to use on conflict markers
   -a --text        treat all files as text
   -p --print       print results instead of overwriting LOCAL
      --no-minimal  no effect (DEPRECATED)
   -h --help        display help and exit
   -q --quiet       suppress output
  [1]