view tests/test-git-export.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).

  $ hg init
  $ echo start > start
  $ hg ci -Amstart
  adding start

New file:

  $ mkdir dir1
  $ echo new > dir1/new
  $ hg ci -Amnew
  adding dir1/new
  $ hg diff --git -r 0
  diff --git a/dir1/new b/dir1/new
  new file mode 100644
  --- /dev/null
  +++ b/dir1/new
  @@ -0,0 +1,1 @@
  +new

Copy:

  $ mkdir dir2
  $ hg cp dir1/new dir1/copy
  $ echo copy1 >> dir1/copy
  $ hg cp dir1/new dir2/copy
  $ echo copy2 >> dir2/copy
  $ hg ci -mcopy
  $ hg diff --git -r 1:tip
  diff --git a/dir1/new b/dir1/copy
  copy from dir1/new
  copy to dir1/copy
  --- a/dir1/new
  +++ b/dir1/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  diff --git a/dir1/new b/dir2/copy
  copy from dir1/new
  copy to dir2/copy
  --- a/dir1/new
  +++ b/dir2/copy
  @@ -1,1 +1,2 @@
   new
  +copy2

Cross and same-directory copies with a relative root:

  $ hg diff --git --root .. -r 1:tip
  abort: .. not under root '$TESTTMP'
  [255]
  $ hg diff --git --root doesnotexist -r 1:tip
  $ hg diff --git --root . -r 1:tip
  diff --git a/dir1/new b/dir1/copy
  copy from dir1/new
  copy to dir1/copy
  --- a/dir1/new
  +++ b/dir1/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  diff --git a/dir1/new b/dir2/copy
  copy from dir1/new
  copy to dir2/copy
  --- a/dir1/new
  +++ b/dir2/copy
  @@ -1,1 +1,2 @@
   new
  +copy2
  $ hg diff --git --root dir1 -r 1:tip
  diff --git a/new b/copy
  copy from new
  copy to copy
  --- a/new
  +++ b/copy
  @@ -1,1 +1,2 @@
   new
  +copy1

  $ hg diff --git --root dir2/ -r 1:tip
  diff --git a/copy b/copy
  new file mode 100644
  --- /dev/null
  +++ b/copy
  @@ -0,0 +1,2 @@
  +new
  +copy2

  $ hg diff --git --root dir1 -r 1:tip -I '**/copy'
  diff --git a/new b/copy
  copy from new
  copy to copy
  --- a/new
  +++ b/copy
  @@ -1,1 +1,2 @@
   new
  +copy1

  $ hg diff --git --root dir1 -r 1:tip dir2
  warning: dir2 not inside relative root dir1

  $ hg diff --git --root dir1 -r 1:tip 'dir2/{copy}'
  warning: dir2/{copy} not inside relative root dir1 (glob)

  $ cd dir1
  $ hg diff --git --root .. -r 1:tip
  diff --git a/dir1/new b/dir1/copy
  copy from dir1/new
  copy to dir1/copy
  --- a/dir1/new
  +++ b/dir1/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  diff --git a/dir1/new b/dir2/copy
  copy from dir1/new
  copy to dir2/copy
  --- a/dir1/new
  +++ b/dir2/copy
  @@ -1,1 +1,2 @@
   new
  +copy2

  $ hg diff --git --root ../.. -r 1:tip
  abort: ../.. not under root '$TESTTMP'
  [255]
  $ hg diff --git --root ../doesnotexist -r 1:tip
  $ hg diff --git --root .. -r 1:tip
  diff --git a/dir1/new b/dir1/copy
  copy from dir1/new
  copy to dir1/copy
  --- a/dir1/new
  +++ b/dir1/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  diff --git a/dir1/new b/dir2/copy
  copy from dir1/new
  copy to dir2/copy
  --- a/dir1/new
  +++ b/dir2/copy
  @@ -1,1 +1,2 @@
   new
  +copy2

  $ hg diff --git --root . -r 1:tip
  diff --git a/new b/copy
  copy from new
  copy to copy
  --- a/new
  +++ b/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  $ hg diff --git --root . -r 1:tip copy
  diff --git a/new b/copy
  copy from new
  copy to copy
  --- a/new
  +++ b/copy
  @@ -1,1 +1,2 @@
   new
  +copy1
  $ hg diff --git --root . -r 1:tip ../dir2
  warning: ../dir2 not inside relative root . (glob)
  $ hg diff --git --root . -r 1:tip '../dir2/*'
  warning: ../dir2/* not inside relative root . (glob)
  $ cd ..

Rename:

  $ hg mv dir1/copy dir1/rename1
  $ echo rename1 >> dir1/rename1
  $ hg mv dir2/copy dir1/rename2
  $ echo rename2 >> dir1/rename2
  $ hg ci -mrename
  $ hg diff --git -r 2:tip
  diff --git a/dir1/copy b/dir1/rename1
  rename from dir1/copy
  rename to dir1/rename1
  --- a/dir1/copy
  +++ b/dir1/rename1
  @@ -1,2 +1,3 @@
   new
   copy1
  +rename1
  diff --git a/dir2/copy b/dir1/rename2
  rename from dir2/copy
  rename to dir1/rename2
  --- a/dir2/copy
  +++ b/dir1/rename2
  @@ -1,2 +1,3 @@
   new
   copy2
  +rename2

Cross and same-directory renames with a relative root:

  $ hg diff --root dir1 --git -r 2:tip
  diff --git a/copy b/rename1
  rename from copy
  rename to rename1
  --- a/copy
  +++ b/rename1
  @@ -1,2 +1,3 @@
   new
   copy1
  +rename1
  diff --git a/rename2 b/rename2
  new file mode 100644
  --- /dev/null
  +++ b/rename2
  @@ -0,0 +1,3 @@
  +new
  +copy2
  +rename2

  $ hg diff --root dir2 --git -r 2:tip
  diff --git a/copy b/copy
  deleted file mode 100644
  --- a/copy
  +++ /dev/null
  @@ -1,2 +0,0 @@
  -new
  -copy2

  $ hg diff --root dir1 --git -r 2:tip -I '**/copy'
  diff --git a/copy b/copy
  deleted file mode 100644
  --- a/copy
  +++ /dev/null
  @@ -1,2 +0,0 @@
  -new
  -copy1

  $ hg diff --root dir1 --git -r 2:tip -I '**/rename*'
  diff --git a/copy b/rename1
  copy from copy
  copy to rename1
  --- a/copy
  +++ b/rename1
  @@ -1,2 +1,3 @@
   new
   copy1
  +rename1
  diff --git a/rename2 b/rename2
  new file mode 100644
  --- /dev/null
  +++ b/rename2
  @@ -0,0 +1,3 @@
  +new
  +copy2
  +rename2

Delete:

  $ hg rm dir1/*
  $ hg ci -mdelete
  $ hg diff --git -r 3:tip
  diff --git a/dir1/new b/dir1/new
  deleted file mode 100644
  --- a/dir1/new
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -new
  diff --git a/dir1/rename1 b/dir1/rename1
  deleted file mode 100644
  --- a/dir1/rename1
  +++ /dev/null
  @@ -1,3 +0,0 @@
  -new
  -copy1
  -rename1
  diff --git a/dir1/rename2 b/dir1/rename2
  deleted file mode 100644
  --- a/dir1/rename2
  +++ /dev/null
  @@ -1,3 +0,0 @@
  -new
  -copy2
  -rename2

  $ cat > src <<EOF
  > 1
  > 2
  > 3
  > 4
  > 5
  > EOF
  $ hg ci -Amsrc
  adding src

#if execbit

chmod 644:

  $ chmod +x src
  $ hg ci -munexec
  $ hg diff --git -r 5:tip
  diff --git a/src b/src
  old mode 100644
  new mode 100755

Rename+mod+chmod:

  $ hg mv src dst
  $ chmod -x dst
  $ echo a >> dst
  $ hg ci -mrenamemod
  $ hg diff --git -r 6:tip
  diff --git a/src b/dst
  old mode 100755
  new mode 100644
  rename from src
  rename to dst
  --- a/src
  +++ b/dst
  @@ -3,3 +3,4 @@
   3
   4
   5
  +a

Nonexistent in tip+chmod:

  $ hg diff --git -r 5:6
  diff --git a/src b/src
  old mode 100644
  new mode 100755

#else

Dummy changes when no exec bit, mocking the execbit commit structure

  $ echo change >> src
  $ hg ci -munexec
  $ hg mv src dst
  $ hg ci -mrenamemod

#endif

Binary diff:

  $ cp "$TESTDIR/binfile.bin" .
  $ hg add binfile.bin
  $ hg diff --git > b.diff
  $ cat b.diff
  diff --git a/binfile.bin b/binfile.bin
  new file mode 100644
  index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..37ba3d1c6f17137d9c5f5776fa040caf5fe73ff9
  GIT binary patch
  literal 593
  zc$@)I0<QguP)<h;3K|Lk000e1NJLTq000mG000mO0ssI2kdbIM00009a7bBm000XU
  z000XU0RWnu7ytkO2XskIMF-Uh9TW;VpMjwv0005-Nkl<ZD9@FWPs=e;7{<>W$NUkd
  zX$nnYLt$-$V!?uy+1V%`z&Eh=ah|duER<4|QWhju3gb^nF*8iYobxWG-qqXl=2~5M
  z*IoDB)sG^CfNuoBmqLTVU^<;@nwHP!1wrWd`{(mHo6VNXWtyh{alzqmsH*yYzpvLT
  zLdY<T=ks|woh-`&01!ej#(xbV1f|pI*=%;d-%F*E*X#ZH`4I%6SS+$EJDE&ct=8po
  ziN#{?_j|kD%Cd|oiqds`xm@;oJ-^?NG3Gdqrs?5u*zI;{nogxsx~^|Fn^Y?Gdc6<;
  zfMJ+iF1J`LMx&A2?dEwNW8ClebzPTbIh{@$hS6*`kH@1d%Lo7fA#}N1)oN7`gm$~V
  z+wDx#)OFqMcE{s!JN0-xhG8ItAjVkJwEcb`3WWlJfU2r?;Pd%dmR+q@mSri5q9_W-
  zaR2~ECX?B2w+zELozC0s*6Z~|QG^f{3I#<`?)Q7U-JZ|q5W;9Q8i_=pBuSzunx=U;
  z9C)5jBoYw9^?EHyQl(M}1OlQcCX>lXB*ODN003Z&P17_@)3Pi=i0wb04<W?v-u}7K
  zXmmQA+wDgE!qR9o8jr`%=ab_&uh(l?R=r;Tjiqon91I2-hIu?57~@*4h7h9uORK#=
  fQItJW-{SoTm)8|5##k|m00000NkvXXu0mjf{mKw4
  

Import binary diff:

  $ hg revert binfile.bin
  $ rm binfile.bin
  $ hg import -mfoo b.diff
  applying b.diff
  $ cmp binfile.bin "$TESTDIR/binfile.bin"

Rename binary file:

  $ hg mv binfile.bin renamed.bin
  $ hg diff --git
  diff --git a/binfile.bin b/renamed.bin
  rename from binfile.bin
  rename to renamed.bin

Diff across many revisions:

  $ hg mv dst dst2
  $ hg ci -m 'mv dst dst2'

  $ echo >> start
  $ hg ci -m 'change start'

  $ hg revert -r -2 start
  $ hg mv dst2 dst3
  $ hg ci -m 'mv dst2 dst3; revert start'

  $ hg diff --git -r 9:11
  diff --git a/dst2 b/dst3
  rename from dst2
  rename to dst3

Reversed:

  $ hg diff --git -r 11:9
  diff --git a/dst3 b/dst2
  rename from dst3
  rename to dst2


  $ echo a >> foo
  $ hg add foo
  $ hg ci -m 'add foo'
  $ echo b >> foo
  $ hg ci -m 'change foo'
  $ hg mv foo bar
  $ hg ci -m 'mv foo bar'
  $ echo c >> bar
  $ hg ci -m 'change bar'

File created before r1 and renamed before r2:

  $ hg diff --git -r -3:-1
  diff --git a/foo b/bar
  rename from foo
  rename to bar
  --- a/foo
  +++ b/bar
  @@ -1,2 +1,3 @@
   a
   b
  +c

Reversed:

  $ hg diff --git -r -1:-3
  diff --git a/bar b/foo
  rename from bar
  rename to foo
  --- a/bar
  +++ b/foo
  @@ -1,3 +1,2 @@
   a
   b
  -c

File created in r1 and renamed before r2:

  $ hg diff --git -r -4:-1
  diff --git a/foo b/bar
  rename from foo
  rename to bar
  --- a/foo
  +++ b/bar
  @@ -1,1 +1,3 @@
   a
  +b
  +c

Reversed:

  $ hg diff --git -r -1:-4
  diff --git a/bar b/foo
  rename from bar
  rename to foo
  --- a/bar
  +++ b/foo
  @@ -1,3 +1,1 @@
   a
  -b
  -c

File created after r1 and renamed before r2:

  $ hg diff --git -r -5:-1
  diff --git a/bar b/bar
  new file mode 100644
  --- /dev/null
  +++ b/bar
  @@ -0,0 +1,3 @@
  +a
  +b
  +c

Reversed:

  $ hg diff --git -r -1:-5
  diff --git a/bar b/bar
  deleted file mode 100644
  --- a/bar
  +++ /dev/null
  @@ -1,3 +0,0 @@
  -a
  -b
  -c


Comparing with the working dir:

  $ echo >> start
  $ hg ci -m 'change start again'

  $ echo > created
  $ hg add created
  $ hg ci -m 'add created'

  $ hg mv created created2
  $ hg ci -m 'mv created created2'

  $ hg mv created2 created3

There's a copy in the working dir:

  $ hg diff --git
  diff --git a/created2 b/created3
  rename from created2
  rename to created3

There's another copy between the original rev and the wd:

  $ hg diff --git -r -2
  diff --git a/created b/created3
  rename from created
  rename to created3

The source of the copy was created after the original rev:

  $ hg diff --git -r -3
  diff --git a/created3 b/created3
  new file mode 100644
  --- /dev/null
  +++ b/created3
  @@ -0,0 +1,1 @@
  +
  $ hg ci -m 'mv created2 created3'


  $ echo > brand-new
  $ hg add brand-new
  $ hg ci -m 'add brand-new'
  $ hg mv brand-new brand-new2

Created in parent of wd; renamed in the wd:

  $ hg diff --git
  diff --git a/brand-new b/brand-new2
  rename from brand-new
  rename to brand-new2

Created between r1 and parent of wd; renamed in the wd:

  $ hg diff --git -r -2
  diff --git a/brand-new2 b/brand-new2
  new file mode 100644
  --- /dev/null
  +++ b/brand-new2
  @@ -0,0 +1,1 @@
  +
  $ hg ci -m 'mv brand-new brand-new2'

One file is copied to many destinations and removed:

  $ hg cp brand-new2 brand-new3
  $ hg mv brand-new2 brand-new3-2
  $ hg ci -m 'multiple renames/copies'
  $ hg diff --git -r -2 -r -1
  diff --git a/brand-new2 b/brand-new3
  rename from brand-new2
  rename to brand-new3
  diff --git a/brand-new2 b/brand-new3-2
  copy from brand-new2
  copy to brand-new3-2

Reversed:

  $ hg diff --git -r -1 -r -2
  diff --git a/brand-new3-2 b/brand-new2
  rename from brand-new3-2
  rename to brand-new2
  diff --git a/brand-new3 b/brand-new3
  deleted file mode 100644
  --- a/brand-new3
  +++ /dev/null
  @@ -1,1 +0,0 @@
  -

There should be a trailing TAB if there are spaces in the file name:

  $ echo foo > 'with spaces'
  $ hg add 'with spaces'
  $ hg diff --git
  diff --git a/with spaces b/with spaces
  new file mode 100644
  --- /dev/null
  +++ b/with spaces	
  @@ -0,0 +1,1 @@
  +foo
  $ hg ci -m 'add filename with spaces'

Additions should be properly marked even in the middle of a merge

  $ hg up -r -2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo "New File" >> inmerge
  $ hg add inmerge
  $ hg ci -m "file in merge"
  created new head
  $ hg up 23
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg diff -g
  diff --git a/inmerge b/inmerge
  new file mode 100644
  --- /dev/null
  +++ b/inmerge
  @@ -0,0 +1,1 @@
  +New File