view tests/test-merge1.t @ 33207:895ecec31c70

revlog: add an experimental option to mitigated delta issues (issue5480)

The general delta heuristic to select a delta do not scale with the number of
branch. The delta base is frequently too far away to be able to reuse a chain
according to the "distance" criteria. This leads to insertion of larger delta (or
even full text) that themselves push the bases for the next delta further away
leading to more large deltas and full texts. This full text and frequent
recomputation throw Mercurial performance in disarray.

For example of a slightly large repository

  280 000 files (2 150 000 versions)
  430 000 changesets (10 000 topological heads)

Number below compares repository with and without the distance criteria:

manifest size:
    with:    21.4 GB
    without:  0.3 GB

store size:
    with:    28.7 GB
    without   7.4 GB

bundle last 15 00 revisions:
    with:    800 seconds
             971 MB
    without:  50 seconds
              73 MB

unbundle time (of the last 15K revisions):
    with:    1150 seconds (~19 minutes)
    without:   35 seconds

Similar issues has been observed in other repositories.


Adding a new option or "feature" on stable is uncommon. However, given that this
issues is making Mercurial practically unusable, I'm exceptionally targeting
this patch for stable.

What is actually needed is a full rework of the delta building and reading
logic. However, that will be a longer process and churn not suitable for stable.

In the meantime, we introduces a quick and dirty mitigation of this in the
'experimental' config space. The new option introduces a way to set the maximum
amount of memory usable to store a diff in memory. This extend the ability for
Mercurial to create chains without removing all safe guard regarding memory
access. The option should be phased out when core has a more proper solution
available.

Setting the limit to '0' remove all limits, setting it to '-1' use the default
limit (textsize x 4).

  $ cat <<EOF > merge
  > import sys, os
  > 
  > try:
  >     import msvcrt
  >     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
  >     msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
  > except ImportError:
  >     pass
  > 
  > print "merging for", os.path.basename(sys.argv[1])
  > EOF
  $ HGMERGE="python ../merge"; export HGMERGE

  $ hg init t
  $ cd t
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"

  $ hg update 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

Test interrupted updates by having a non-empty dir with the same name as one
of the files in a commit we're updating to

  $ mkdir b && touch b/nonempty
  $ hg up
  abort: *: '$TESTTMP/t/b' (glob)
  [255]
  $ hg ci
  abort: last update was interrupted
  (use 'hg update' to get a consistent checkout)
  [255]
  $ hg sum
  parent: 0:538afb845929 
   commit #0
  branch: default
  commit: 1 unknown (interrupted update)
  update: 1 new changesets (update)
  phases: 2 draft
  $ rm b/nonempty
  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg sum
  parent: 1:b8bb4a988f25 tip
   commit #1
  branch: default
  commit: (clean)
  update: (current)
  phases: 2 draft

Prepare a basic merge

  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #2"
  created new head
  $ echo This is file b1 > b
no merges expected
  $ hg merge -P 1
  changeset:   1:b8bb4a988f25
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     commit #1
  
  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg diff --nodates
  diff -r 49035e18a8e6 b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +This is file b1
  $ hg status
  M b
  $ cd ..; rm -r t

  $ hg init t
  $ cd t
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"

  $ hg update 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #2"
  created new head
  $ echo This is file b2 > b
merge should fail
  $ hg merge 1
  b: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]

#if symlink
symlinks to directories should be treated as regular files (issue5027)
  $ rm b
  $ ln -s 'This is file b2' b
  $ hg merge 1
  b: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]
symlinks shouldn't be followed
  $ rm b
  $ echo This is file b1 > .hg/b
  $ ln -s .hg/b b
  $ hg merge 1
  b: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]

  $ rm b
  $ echo This is file b2 > b
#endif

bad config
  $ hg merge 1 --config merge.checkunknown=x
  abort: merge.checkunknown not valid ('x' is none of 'abort', 'ignore', 'warn')
  [255]
this merge should fail
  $ hg merge 1 --config merge.checkunknown=abort
  b: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]

this merge should warn
  $ hg merge 1 --config merge.checkunknown=warn
  b: replacing untracked file
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat b.orig
  This is file b2
  $ hg up --clean 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mv b.orig b

this merge should silently ignore
  $ cat b
  This is file b2
  $ hg merge 1 --config merge.checkunknown=ignore
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

merge.checkignored
  $ hg up --clean 1
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ cat >> .hgignore << EOF
  > remoteignored
  > EOF
  $ echo This is file localignored3 > localignored
  $ echo This is file remoteignored3 > remoteignored
  $ hg add .hgignore localignored remoteignored
  $ hg commit -m "commit #3"

  $ hg up 2
  1 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ cat >> .hgignore << EOF
  > localignored
  > EOF
  $ hg add .hgignore
  $ hg commit -m "commit #4"

remote .hgignore shouldn't be used for determining whether a file is ignored
  $ echo This is file remoteignored4 > remoteignored
  $ hg merge 3 --config merge.checkignored=ignore --config merge.checkunknown=abort
  remoteignored: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg merge 3 --config merge.checkignored=abort --config merge.checkunknown=ignore
  merging .hgignore
  merging for .hgignore
  3 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat remoteignored
  This is file remoteignored3
  $ cat remoteignored.orig
  This is file remoteignored4
  $ rm remoteignored.orig

local .hgignore should be used for that
  $ hg up --clean 4
  1 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ echo This is file localignored4 > localignored
also test other conflicting files to see we output the full set of warnings
  $ echo This is file b2 > b
  $ hg merge 3 --config merge.checkignored=abort --config merge.checkunknown=abort
  b: untracked file differs
  localignored: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg merge 3 --config merge.checkignored=abort --config merge.checkunknown=ignore
  localignored: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg merge 3 --config merge.checkignored=warn --config merge.checkunknown=abort
  b: untracked file differs
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg merge 3 --config merge.checkignored=warn --config merge.checkunknown=warn
  b: replacing untracked file
  localignored: replacing untracked file
  merging .hgignore
  merging for .hgignore
  3 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ cat localignored
  This is file localignored3
  $ cat localignored.orig
  This is file localignored4
  $ rm localignored.orig

  $ cat b.orig
  This is file b2
  $ hg up --clean 2
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ mv b.orig b

this merge of b should work
  $ cat b
  This is file b2
  $ hg merge -f 1
  merging b
  merging for b
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg diff --nodates
  diff -r 49035e18a8e6 b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +This is file b2
  $ hg status
  M b
  $ cd ..; rm -r t

  $ hg init t
  $ cd t
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ echo This is file b22 > b
  $ hg commit -m "commit #2"
  $ hg update 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #3"
  created new head

Contents of b should be "this is file b1"
  $ cat b
  This is file b1

  $ echo This is file b22 > b
merge fails
  $ hg merge 2
  abort: uncommitted changes
  (use 'hg status' to list changes)
  [255]
merge expected!
  $ hg merge -f 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg diff --nodates
  diff -r 85de557015a8 b
  --- a/b
  +++ b/b
  @@ -1,1 +1,1 @@
  -This is file b1
  +This is file b22
  $ hg status
  M b
  $ cd ..; rm -r t

  $ hg init t
  $ cd t
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ echo This is file b22 > b
  $ hg commit -m "commit #2"
  $ hg update 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #3"
  created new head
  $ echo This is file b33 > b
merge of b should fail
  $ hg merge 2
  abort: uncommitted changes
  (use 'hg status' to list changes)
  [255]
merge of b expected
  $ hg merge -f 2
  merging b
  merging for b
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg diff --nodates
  diff -r 85de557015a8 b
  --- a/b
  +++ b/b
  @@ -1,1 +1,1 @@
  -This is file b1
  +This is file b33
  $ hg status
  M b

Test for issue2364

  $ hg up -qC .
  $ hg rm b
  $ hg ci -md
  $ hg revert -r -2 b
  $ hg up -q -- -2

Test that updated files are treated as "modified", when
'merge.update()' is aborted before 'merge.recordupdates()' (= parents
aren't changed), even if none of mode, size and timestamp of them
isn't changed on the filesystem (see also issue4583).

  $ cat > $TESTTMP/abort.py <<EOF
  > # emulate aborting before "recordupdates()". in this case, files
  > # are changed without updating dirstate
  > from mercurial import extensions, merge, error
  > def applyupdates(orig, *args, **kwargs):
  >     orig(*args, **kwargs)
  >     raise error.Abort('intentional aborting')
  > def extsetup(ui):
  >     extensions.wrapfunction(merge, "applyupdates", applyupdates)
  > EOF

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

(file gotten from other revision)

  $ hg update -q -C 2
  $ echo 'THIS IS FILE B5' > b
  $ hg commit -m 'commit #5'

  $ hg update -q -C 3
  $ cat b
  This is file b1
  $ touch -t 200001010000 b
  $ hg debugrebuildstate

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
  > abort = $TESTTMP/abort.py
  > EOF
  $ hg merge 5
  abort: intentional aborting
  [255]
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > fakedirstatewritetime = !
  > abort = !
  > EOF

  $ cat b
  THIS IS FILE B5
  $ touch -t 200001010000 b
  $ hg status -A b
  M b

(file merged from other revision)

  $ hg update -q -C 3
  $ echo 'this is file b6' > b
  $ hg commit -m 'commit #6'
  created new head

  $ cat b
  this is file b6
  $ touch -t 200001010000 b
  $ hg debugrebuildstate

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > fakedirstatewritetime = $TESTDIR/fakedirstatewritetime.py
  > abort = $TESTTMP/abort.py
  > EOF
  $ hg merge --tool internal:other 5
  abort: intentional aborting
  [255]
  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > fakedirstatewritetime = !
  > abort = !
  > EOF

  $ cat b
  THIS IS FILE B5
  $ touch -t 200001010000 b
  $ hg status -A b
  M b

  $ cd ..