view tests/test-merge1.t @ 34824:e2ad93bcc084

revlog: introduce an experimental flag to slice chunks reads when too sparse

Delta chains can become quite sparse if there is a lot of unrelated data between
relevant pieces. Right now, revlog always reads all the necessary data for the
delta chain in one single read. This can lead to a lot of unrelated data to be
read (see issue5482 for more details).
One can use the `experimental.maxdeltachainspan` option with a large value
(or -1) to easily produce a very sparse delta chain.

This change introduces the ability to slice the chunks retrieval into  multiple
reads, skipping large sections of unrelated data. Preliminary testing shows
interesting results. For example the peak memory consumption to read a manifest
on a large repository is reduced from 600MB to 250MB (200MB without
maxdeltachainspan). However, the slicing itself and the multiple reads can have
an negative impact on performance. This is why the new feature is hidden behind
an experimental flag.

Future changesets will add various parameters to control the slicing heuristics.
We hope to experiment a wide variety of repositories during 4.4 and hopefully
turn the feature on by default in 4.5.
As a first try, the algorithm itself is prone to deep changes. However, we wish
to define APIs and have a baseline to work on.

  $ cat <<EOF > merge
  > from __future__ import print_function
  > 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
  b: untracked directory conflicts with file
  abort: untracked files in working directory differ from files in requested revision
  [255]
  $ hg ci
  nothing changed
  [1]
  $ hg sum
  parent: 0:538afb845929 
   commit #0
  branch: default
  commit: 1 unknown (clean)
  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
  > from __future__ import absolute_import
  > # emulate aborting before "recordupdates()". in this case, files
  > # are changed without updating dirstate
  > from mercurial import (
  >   error,
  >   extensions,
  >   merge,
  > )
  > 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 ..