view tests/test-rebase-collapse.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 >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > mq=
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}: '{desc}' {branches}\n"
  > tglogp = log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  > EOF

Create repo a:

  $ hg init a
  $ cd a
  $ hg unbundle "$TESTDIR/bundles/rebase.hg"
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up tip
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg tglog
  @  7: 'H'
  |
  | o  6: 'G'
  |/|
  o |  5: 'F'
  | |
  | o  4: 'E'
  |/
  | o  3: 'D'
  | |
  | o  2: 'C'
  | |
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ cd ..


Rebasing B onto H and collapsing changesets with different phases:


  $ hg clone -q -u 3 a a1
  $ cd a1

  $ hg phase --force --secret 3

  $ cat > $TESTTMP/editor.sh <<EOF
  > echo "==== before editing"
  > cat \$1
  > echo "===="
  > echo "edited manually" >> \$1
  > EOF
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg rebase --collapse --keepbranches -e --dest 7
  rebasing 1:42ccdea3bb16 "B"
  rebasing 2:5fddd98957c8 "C"
  rebasing 3:32af7686d403 "D"
  ==== before editing
  Collapsed revision
  * B
  * C
  * D
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to abort commit.
  HG: --
  HG: user: Nicolas Dumazet <[e-mail]>
  HG: branch 'default'
  HG: added B
  HG: added C
  HG: added D
  ====
  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/42ccdea3bb16-3cb021d3-backup.hg (glob)

  $ hg tglogp
  @  5:secret 'Collapsed revision
  |  * B
  |  * C
  |  * D
  |
  |
  |  edited manually'
  o  4:draft 'H'
  |
  | o  3:draft 'G'
  |/|
  o |  2:draft 'F'
  | |
  | o  1:draft 'E'
  |/
  o  0:draft 'A'
  
  $ hg manifest --rev tip
  A
  B
  C
  D
  F
  H

  $ cd ..


Rebasing E onto H:

  $ hg clone -q -u . a a2
  $ cd a2

  $ hg phase --force --secret 6
  $ hg rebase --source 4 --collapse --dest 7
  rebasing 4:9520eea781bc "E"
  rebasing 6:eea13746799a "G"
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/9520eea781bc-fcd8edd4-backup.hg (glob)

  $ hg tglog
  o  6: 'Collapsed revision
  |  * E
  |  * G'
  @  5: 'H'
  |
  o  4: 'F'
  |
  | o  3: 'D'
  | |
  | o  2: 'C'
  | |
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ hg manifest --rev tip
  A
  E
  F
  H

  $ cd ..

Rebasing G onto H with custom message:

  $ hg clone -q -u . a a3
  $ cd a3

  $ hg rebase --base 6 -m 'custom message'
  abort: message can only be specified with collapse
  [255]

  $ cat > $TESTTMP/checkeditform.sh <<EOF
  > env | grep HGEDITFORM
  > true
  > EOF
  $ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg rebase --source 4 --collapse -m 'custom message' -e --dest 7
  rebasing 4:9520eea781bc "E"
  rebasing 6:eea13746799a "G"
  HGEDITFORM=rebase.collapse
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/9520eea781bc-fcd8edd4-backup.hg (glob)

  $ hg tglog
  o  6: 'custom message'
  |
  @  5: 'H'
  |
  o  4: 'F'
  |
  | o  3: 'D'
  | |
  | o  2: 'C'
  | |
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ hg manifest --rev tip
  A
  E
  F
  H

  $ cd ..

Create repo b:

  $ hg init b
  $ cd b

  $ echo A > A
  $ hg ci -Am A
  adding A
  $ echo B > B
  $ hg ci -Am B
  adding B

  $ hg up -q 0

  $ echo C > C
  $ hg ci -Am C
  adding C
  created new head

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ echo D > D
  $ hg ci -Am D
  adding D

  $ hg up -q 1

  $ echo E > E
  $ hg ci -Am E
  adding E
  created new head

  $ echo F > F
  $ hg ci -Am F
  adding F

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m G

  $ hg up -q 0

  $ echo H > H
  $ hg ci -Am H
  adding H
  created new head

  $ hg tglog
  @  7: 'H'
  |
  | o    6: 'G'
  | |\
  | | o  5: 'F'
  | | |
  | | o  4: 'E'
  | | |
  | o |  3: 'D'
  | |\|
  | o |  2: 'C'
  |/ /
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ cd ..


Rebase and collapse - more than one external (fail):

  $ hg clone -q -u . b b1
  $ cd b1

  $ hg rebase -s 2 --dest 7 --collapse
  abort: unable to collapse on top of 7, there is more than one external parent: 1, 5
  [255]

Rebase and collapse - E onto H:

  $ hg rebase -s 4 --dest 7 --collapse # root (4) is not a merge
  rebasing 4:8a5212ebc852 "E"
  rebasing 5:7f219660301f "F"
  rebasing 6:c772a8b2dc17 "G"
  saved backup bundle to $TESTTMP/b1/.hg/strip-backup/8a5212ebc852-75046b61-backup.hg (glob)

  $ hg tglog
  o    5: 'Collapsed revision
  |\   * E
  | |  * F
  | |  * G'
  | @  4: 'H'
  | |
  o |    3: 'D'
  |\ \
  | o |  2: 'C'
  | |/
  o /  1: 'B'
  |/
  o  0: 'A'
  
  $ hg manifest --rev tip
  A
  C
  D
  E
  F
  H

  $ cd ..




Test that branchheads cache is updated correctly when doing a strip in which
the parent of the ancestor node to be stripped does not become a head and also,
the parent of a node that is a child of the node stripped becomes a head (node
3). The code is now much simpler and we could just test a simpler scenario
We keep it the test this way in case new complexity is injected.

  $ hg clone -q -u . b b2
  $ cd b2

  $ hg heads --template="{rev}:{node} {branch}\n"
  7:c65502d4178782309ce0574c5ae6ee9485a9bafa default
  6:c772a8b2dc17629cec88a19d09c926c4814b12c7 default

  $ cat $TESTTMP/b2/.hg/cache/branch2-served
  c65502d4178782309ce0574c5ae6ee9485a9bafa 7
  c772a8b2dc17629cec88a19d09c926c4814b12c7 o default
  c65502d4178782309ce0574c5ae6ee9485a9bafa o default

  $ hg strip 4
  saved backup bundle to $TESTTMP/b2/.hg/strip-backup/8a5212ebc852-75046b61-backup.hg (glob)

  $ cat $TESTTMP/b2/.hg/cache/branch2-served
  c65502d4178782309ce0574c5ae6ee9485a9bafa 4
  2870ad076e541e714f3c2bc32826b5c6a6e5b040 o default
  c65502d4178782309ce0574c5ae6ee9485a9bafa o default

  $ hg heads --template="{rev}:{node} {branch}\n"
  4:c65502d4178782309ce0574c5ae6ee9485a9bafa default
  3:2870ad076e541e714f3c2bc32826b5c6a6e5b040 default

  $ cd ..






Create repo c:

  $ hg init c
  $ cd c

  $ echo A > A
  $ hg ci -Am A
  adding A
  $ echo B > B
  $ hg ci -Am B
  adding B

  $ hg up -q 0

  $ echo C > C
  $ hg ci -Am C
  adding C
  created new head

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ echo D > D
  $ hg ci -Am D
  adding D

  $ hg up -q 1

  $ echo E > E
  $ hg ci -Am E
  adding E
  created new head
  $ echo F > E
  $ hg ci -m 'F'

  $ echo G > G
  $ hg ci -Am G
  adding G

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg ci -m H

  $ hg up -q 0

  $ echo I > I
  $ hg ci -Am I
  adding I
  created new head

  $ hg tglog
  @  8: 'I'
  |
  | o    7: 'H'
  | |\
  | | o  6: 'G'
  | | |
  | | o  5: 'F'
  | | |
  | | o  4: 'E'
  | | |
  | o |  3: 'D'
  | |\|
  | o |  2: 'C'
  |/ /
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ cd ..


Rebase and collapse - E onto I:

  $ hg clone -q -u . c c1
  $ cd c1

  $ hg rebase -s 4 --dest 8 --collapse # root (4) is not a merge
  rebasing 4:8a5212ebc852 "E"
  rebasing 5:dca5924bb570 "F"
  merging E
  rebasing 6:55a44ad28289 "G"
  rebasing 7:417d3b648079 "H"
  saved backup bundle to $TESTTMP/c1/.hg/strip-backup/8a5212ebc852-f95d0879-backup.hg (glob)

  $ hg tglog
  o    5: 'Collapsed revision
  |\   * E
  | |  * F
  | |  * G
  | |  * H'
  | @  4: 'I'
  | |
  o |    3: 'D'
  |\ \
  | o |  2: 'C'
  | |/
  o /  1: 'B'
  |/
  o  0: 'A'
  
  $ hg manifest --rev tip
  A
  C
  D
  E
  G
  I

  $ hg up tip -q
  $ cat E
  F

  $ cd ..


Create repo d:

  $ hg init d
  $ cd d

  $ echo A > A
  $ hg ci -Am A
  adding A
  $ echo B > B
  $ hg ci -Am B
  adding B
  $ echo C > C
  $ hg ci -Am C
  adding C

  $ hg up -q 1

  $ echo D > D
  $ hg ci -Am D
  adding D
  created new head
  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg ci -m E

  $ hg up -q 0

  $ echo F > F
  $ hg ci -Am F
  adding F
  created new head

  $ hg tglog
  @  5: 'F'
  |
  | o    4: 'E'
  | |\
  | | o  3: 'D'
  | | |
  | o |  2: 'C'
  | |/
  | o  1: 'B'
  |/
  o  0: 'A'
  
  $ cd ..


Rebase and collapse - B onto F:

  $ hg clone -q -u . d d1
  $ cd d1

  $ hg rebase -s 1 --collapse --dest 5
  rebasing 1:27547f69f254 "B"
  rebasing 2:f838bfaca5c7 "C"
  rebasing 3:7bbcd6078bcc "D"
  rebasing 4:0a42590ed746 "E"
  saved backup bundle to $TESTTMP/d1/.hg/strip-backup/27547f69f254-9a3f7d92-backup.hg (glob)

  $ hg tglog
  o  2: 'Collapsed revision
  |  * B
  |  * C
  |  * D
  |  * E'
  @  1: 'F'
  |
  o  0: 'A'
  
  $ hg manifest --rev tip
  A
  B
  C
  D
  F

Interactions between collapse and keepbranches
  $ cd ..
  $ hg init e
  $ cd e
  $ echo 'a' > a
  $ hg ci -Am 'A'
  adding a

  $ hg branch 'one'
  marked working directory as branch one
  (branches are permanent and global, did you want a bookmark?)
  $ echo 'b' > b
  $ hg ci -Am 'B'
  adding b

  $ hg branch 'two'
  marked working directory as branch two
  $ echo 'c' > c
  $ hg ci -Am 'C'
  adding c

  $ hg up -q 0
  $ echo 'd' > d
  $ hg ci -Am 'D'
  adding d

  $ hg tglog
  @  3: 'D'
  |
  | o  2: 'C' two
  | |
  | o  1: 'B' one
  |/
  o  0: 'A'
  
  $ hg rebase --keepbranches --collapse -s 1 -d 3
  abort: cannot collapse multiple named branches
  [255]

  $ repeatchange() {
  >   hg checkout $1
  >   hg cp d z
  >   echo blah >> z
  >   hg commit -Am "$2" --user "$3"
  > }
  $ repeatchange 3 "E" "user1"
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ repeatchange 3 "E" "user2"
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  created new head
  $ hg tglog
  @  5: 'E'
  |
  | o  4: 'E'
  |/
  o  3: 'D'
  |
  | o  2: 'C' two
  | |
  | o  1: 'B' one
  |/
  o  0: 'A'
  
  $ hg rebase -s 5 -d 4
  rebasing 5:fbfb97b1089a "E" (tip)
  note: rebase of 5:fbfb97b1089a created no changes to commit
  saved backup bundle to $TESTTMP/e/.hg/strip-backup/fbfb97b1089a-553e1d85-backup.hg (glob)
  $ hg tglog
  @  4: 'E'
  |
  o  3: 'D'
  |
  | o  2: 'C' two
  | |
  | o  1: 'B' one
  |/
  o  0: 'A'
  
  $ hg export tip
  # HG changeset patch
  # User user1
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID f338eb3c2c7cc5b5915676a2376ba7ac558c5213
  # Parent  41acb9dca9eb976e84cd21fcb756b4afa5a35c09
  E
  
  diff -r 41acb9dca9eb -r f338eb3c2c7c z
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/z	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,2 @@
  +d
  +blah

  $ cd ..

Rebase, collapse and copies

  $ hg init copies
  $ cd copies
  $ hg unbundle "$TESTDIR/bundles/renames.hg"
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 11 changes to 7 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up -q tip
  $ hg tglog
  @  3: 'move2'
  |
  o  2: 'move1'
  |
  | o  1: 'change'
  |/
  o  0: 'add'
  
  $ hg rebase --collapse -d 1
  rebasing 2:6e7340ee38c0 "move1"
  merging a and d to d
  merging b and e to e
  merging c and f to f
  rebasing 3:338e84e2e558 "move2" (tip)
  merging f and c to c
  merging e and g to g
  saved backup bundle to $TESTTMP/copies/.hg/strip-backup/6e7340ee38c0-ef8ef003-backup.hg (glob)
  $ hg st
  $ hg st --copies --change tip
  A d
    a
  A g
    b
  R b
  $ hg up tip -q
  $ cat c
  c
  c
  $ cat d
  a
  a
  $ cat g
  b
  b
  $ hg log -r . --template "{file_copies}\n"
  d (a)g (b)

Test collapsing a middle revision in-place

  $ hg tglog
  @  2: 'Collapsed revision
  |  * move1
  |  * move2'
  o  1: 'change'
  |
  o  0: 'add'
  
  $ hg rebase --collapse -r 1 -d 0
  abort: can't remove original changesets with unrebased descendants
  (use --keep to keep original changesets)
  [255]

Test collapsing in place

  $ hg rebase --collapse -b . -d 0
  rebasing 1:1352765a01d4 "change"
  rebasing 2:64b456429f67 "Collapsed revision" (tip)
  saved backup bundle to $TESTTMP/copies/.hg/strip-backup/1352765a01d4-45a352ea-backup.hg (glob)
  $ hg st --change tip --copies
  M a
  M c
  A d
    a
  A g
    b
  R b
  $ hg up tip -q
  $ cat a
  a
  a
  $ cat c
  c
  c
  $ cat d
  a
  a
  $ cat g
  b
  b
  $ cd ..


Test stripping a revision with another child

  $ hg init f
  $ cd f

  $ echo A > A
  $ hg ci -Am A
  adding A
  $ echo B > B
  $ hg ci -Am B
  adding B

  $ hg up -q 0

  $ echo C > C
  $ hg ci -Am C
  adding C
  created new head

  $ hg tglog
  @  2: 'C'
  |
  | o  1: 'B'
  |/
  o  0: 'A'
  


  $ hg heads --template="{rev}:{node} {branch}: {desc}\n"
  2:c5cefa58fd557f84b72b87f970135984337acbc5 default: C
  1:27547f69f25460a52fff66ad004e58da7ad3fb56 default: B

  $ hg strip 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/f/.hg/strip-backup/c5cefa58fd55-629429f4-backup.hg (glob)

  $ hg tglog
  o  1: 'B'
  |
  @  0: 'A'
  


  $ hg heads --template="{rev}:{node} {branch}: {desc}\n"
  1:27547f69f25460a52fff66ad004e58da7ad3fb56 default: B

  $ cd ..

Test collapsing changes that add then remove a file

  $ hg init collapseaddremove
  $ cd collapseaddremove

  $ touch base
  $ hg commit -Am base
  adding base
  $ touch a
  $ hg commit -Am a
  adding a
  $ hg rm a
  $ touch b
  $ hg commit -Am b
  adding b
  $ hg book foo
  $ hg rebase -d 0 -r "1::2" --collapse -m collapsed
  rebasing 1:6d8d9f24eec3 "a"
  rebasing 2:1cc73eca5ecc "b" (tip foo)
  saved backup bundle to $TESTTMP/collapseaddremove/.hg/strip-backup/6d8d9f24eec3-77d3b6e2-backup.hg (glob)
  $ hg log -G --template "{rev}: '{desc}' {bookmarks}"
  @  1: 'collapsed' foo
  |
  o  0: 'base'
  
  $ hg manifest --rev tip
  b
  base

  $ cd ..

Test that rebase --collapse will remember message after
running into merge conflict and invoking rebase --continue.

  $ hg init collapse_remember_message
  $ cd collapse_remember_message
  $ touch a
  $ hg add a
  $ hg commit -m "a"
  $ echo "a-default" > a
  $ hg commit -m "a-default"
  $ hg update -r 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch dev
  marked working directory as branch dev
  (branches are permanent and global, did you want a bookmark?)
  $ echo "a-dev" > a
  $ hg commit -m "a-dev"
  $ hg rebase --collapse -m "a-default-dev" -d 1
  rebasing 2:b8d8db2b242d "a-dev" (tip)
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ rm a.orig
  $ hg resolve --mark a
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  rebasing 2:b8d8db2b242d "a-dev" (tip)
  saved backup bundle to $TESTTMP/collapse_remember_message/.hg/strip-backup/b8d8db2b242d-f474c19a-backup.hg (glob)
  $ hg log
  changeset:   2:45ba1d1a8665
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a-default-dev
  
  changeset:   1:3c8db56a44bc
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a-default
  
  changeset:   0:3903775176ed
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
  $ cd ..