view tests/test-rebase-cache.t @ 30561:7c0c722d568d

bdiff: early pruning of common prefix before doing expensive computations

It seems quite common that files don't change completely. New lines are often
pretty much appended, and modifications will often only change a small section
of the file which on average will be in the middle.

There can thus be a big win by pruning a common prefix before starting the more
expensive search for longest common substrings.

Worst case, it will scan through a long sequence of similar bytes without
encountering a newline. Splitlines will then have to do the same again ...
twice for each side. If similar lines are found, splitlines will save the
double iteration and hashing of the lines ... plus there will be less lines to
find common substrings in.

This change might in some cases make the algorith pick shorter or less optimal
common substrings. We can't have the cake and eat it.

This make hg --time bundle --base null -r 4.0 go from 14.5 to 15 s - a 3%
increase.

On mozilla-unified:
perfbdiff -m 3041e4d59df2
! wall 0.053088 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) to
! wall 0.024618 comb 0.020000 user 0.020000 sys 0.000000 (best of 116)
perfbdiff 0e9928989e9c --alldata --count 10
! wall 0.702075 comb 0.700000 user 0.700000 sys 0.000000 (best of 15) to
! wall 0.579235 comb 0.580000 user 0.580000 sys 0.000000 (best of 18)

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > mq=
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog  = log -G --template "{rev}: '{desc}' {branches}\n"
  > theads = heads --template "{rev}: '{desc}' {branches}\n"
  > EOF

  $ hg init a
  $ cd a

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

  $ hg branch branch1
  marked working directory as branch branch1
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -m 'branch1'

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

  $ hg up -q 0

  $ hg branch branch2
  marked working directory as branch branch2
  $ hg ci -m 'branch2'

  $ echo c > C
  $ hg ci -Am C
  adding C

  $ hg up -q 2

  $ hg branch -f branch2
  marked working directory as branch branch2
  $ echo d > d
  $ hg ci -Am D
  adding d
  created new head

  $ echo e > e
  $ hg ci -Am E
  adding e

  $ hg update default
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved

  $ hg branch branch3
  marked working directory as branch branch3
  $ hg ci -m 'branch3'

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

  $ cd ..


Rebase part of branch2 (5-6) onto branch3 (8):

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

  $ hg tglog
  @  8: 'F' branch3
  |
  o  7: 'branch3' branch3
  |
  | o  6: 'E' branch2
  | |
  | o  5: 'D' branch2
  | |
  | | o  4: 'C' branch2
  | | |
  +---o  3: 'branch2' branch2
  | |
  | o  2: 'B' branch1
  | |
  | o  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ hg branches
  branch3                        8:4666b71e8e32
  branch2                        6:5097051d331d
  branch1                        2:0a03079c47fd (inactive)
  default                        0:1994f17a630e (inactive)

  $ hg theads
  8: 'F' branch3
  6: 'E' branch2
  4: 'C' branch2
  2: 'B' branch1
  0: 'A' 

  $ hg rebase -s 5 -d 8
  rebasing 5:635859577d0b "D"
  rebasing 6:5097051d331d "E"
  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/635859577d0b-89160bff-backup.hg (glob)

  $ hg branches
  branch3                        8:466cdfb14b62
  branch2                        4:e4fdb121d036
  branch1                        2:0a03079c47fd
  default                        0:1994f17a630e (inactive)

  $ hg theads
  8: 'E' branch3
  4: 'C' branch2
  2: 'B' branch1
  0: 'A' 

  $ hg tglog
  o  8: 'E' branch3
  |
  o  7: 'D' branch3
  |
  @  6: 'F' branch3
  |
  o  5: 'branch3' branch3
  |
  | o  4: 'C' branch2
  | |
  | o  3: 'branch2' branch2
  |/
  | o  2: 'B' branch1
  | |
  | o  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ cd ..


Rebase head of branch3 (8) onto branch2 (6):

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

  $ hg tglog
  @  8: 'F' branch3
  |
  o  7: 'branch3' branch3
  |
  | o  6: 'E' branch2
  | |
  | o  5: 'D' branch2
  | |
  | | o  4: 'C' branch2
  | | |
  +---o  3: 'branch2' branch2
  | |
  | o  2: 'B' branch1
  | |
  | o  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ hg rebase -s 8 -d 6
  rebasing 8:4666b71e8e32 "F" (tip)
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/4666b71e8e32-fc1c4e96-backup.hg (glob)

  $ hg branches
  branch2                        8:6b4bdc1b5ac0
  branch3                        7:653b9feb4616
  branch1                        2:0a03079c47fd (inactive)
  default                        0:1994f17a630e (inactive)

  $ hg theads
  8: 'F' branch2
  7: 'branch3' branch3
  4: 'C' branch2
  2: 'B' branch1
  0: 'A' 

  $ hg tglog
  @  8: 'F' branch2
  |
  | o  7: 'branch3' branch3
  | |
  o |  6: 'E' branch2
  | |
  o |  5: 'D' branch2
  | |
  | | o  4: 'C' branch2
  | | |
  | | o  3: 'branch2' branch2
  | |/
  o |  2: 'B' branch1
  | |
  o |  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ hg verify -q

  $ cd ..


Rebase entire branch3 (7-8) onto branch2 (6):

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

  $ hg tglog
  @  8: 'F' branch3
  |
  o  7: 'branch3' branch3
  |
  | o  6: 'E' branch2
  | |
  | o  5: 'D' branch2
  | |
  | | o  4: 'C' branch2
  | | |
  +---o  3: 'branch2' branch2
  | |
  | o  2: 'B' branch1
  | |
  | o  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ hg rebase -s 7 -d 6
  rebasing 7:653b9feb4616 "branch3"
  note: rebase of 7:653b9feb4616 created no changes to commit
  rebasing 8:4666b71e8e32 "F" (tip)
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/653b9feb4616-3c88de16-backup.hg (glob)

  $ hg branches
  branch2                        7:6b4bdc1b5ac0
  branch1                        2:0a03079c47fd (inactive)
  default                        0:1994f17a630e (inactive)

  $ hg theads
  7: 'F' branch2
  4: 'C' branch2
  2: 'B' branch1
  0: 'A' 

  $ hg tglog
  @  7: 'F' branch2
  |
  o  6: 'E' branch2
  |
  o  5: 'D' branch2
  |
  | o  4: 'C' branch2
  | |
  | o  3: 'branch2' branch2
  | |
  o |  2: 'B' branch1
  | |
  o |  1: 'branch1' branch1
  |/
  o  0: 'A'
  
  $ hg verify -q

Stripping multiple branches in one go bypasses the fast-case code to
update the branch cache.

  $ hg strip 2
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/0a03079c47fd-11b7c407-backup.hg (glob)

  $ hg tglog
  o  3: 'C' branch2
  |
  o  2: 'branch2' branch2
  |
  | @  1: 'branch1' branch1
  |/
  o  0: 'A'
  

  $ hg branches
  branch2                        3:e4fdb121d036
  branch1                        1:63379ac49655
  default                        0:1994f17a630e (inactive)

  $ hg theads
  3: 'C' branch2
  1: 'branch1' branch1
  0: 'A' 

Fast path branchcache code should not be invoked if branches stripped is not
the same as branches remaining.

  $ hg init b
  $ cd b

  $ hg branch branch1
  marked working directory as branch branch1
  (branches are permanent and global, did you want a bookmark?)
  $ hg ci -m 'branch1'

  $ hg branch branch2
  marked working directory as branch branch2
  $ hg ci -m 'branch2'

  $ hg branch -f branch1
  marked working directory as branch branch1

  $ echo a > A
  $ hg ci -Am A
  adding A
  created new head

  $ hg tglog
  @  2: 'A' branch1
  |
  o  1: 'branch2' branch2
  |
  o  0: 'branch1' branch1
  

  $ hg theads
  2: 'A' branch1
  1: 'branch2' branch2

  $ hg strip 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/a3/b/.hg/strip-backup/a5b4b27ed7b4-a3b6984e-backup.hg (glob)

  $ hg theads
  1: 'branch2' branch2
  0: 'branch1' branch1


Make sure requesting to strip a revision already stripped does not confuse things.
Try both orders.

  $ cd ..

  $ hg init c
  $ cd c

  $ 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
  $ echo d > d
  $ hg ci -Am D
  adding d
  $ echo e > e
  $ hg ci -Am E
  adding e

  $ hg tglog
  @  4: 'E'
  |
  o  3: 'D'
  |
  o  2: 'C'
  |
  o  1: 'B'
  |
  o  0: 'A'
  

  $ hg strip 3 4
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/67a385d4e6f2-b9243789-backup.hg (glob)

  $ hg theads
  2: 'C' 

  $ hg strip 2 1
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  saved backup bundle to $TESTTMP/a3/c/.hg/strip-backup/6c81ed0049f8-a687065f-backup.hg (glob)

  $ hg theads
  0: 'A' 

Make sure rebase does not break for phase/filter related reason
----------------------------------------------------------------
(issue3858)

  $ cd ..

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > logtemplate={rev} {desc} {phase}\n
  > EOF


  $ hg init c4
  $ cd c4

  $ echo a > a
  $ hg ci -Am A
  adding a
  $ echo b > b
  $ hg ci -Am B
  adding b
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo c > c
  $ hg ci -Am C
  adding c
  created new head
  $ hg up 1
  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 ci -m d
  $ hg up 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo e > e
  $ hg ci -Am E
  adding e
  created new head
  $ hg merge 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m F
  $ hg up 3
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo g > g
  $ hg ci -Am G
  adding g
  created new head
  $ echo h > h
  $ hg ci -Am H
  adding h
  $ hg up 5
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo i > i
  $ hg ci -Am I
  adding i

Turn most changeset public

  $ hg ph -p 7

  $ hg heads
  8 I draft
  7 H public
  $ hg log -G
  @  8 I draft
  |
  | o  7 H public
  | |
  | o  6 G public
  | |
  o |  5 F draft
  |\|
  o |  4 E draft
  | |
  | o  3 d public
  |/|
  o |  2 C public
  | |
  | o  1 B public
  |/
  o  0 A public
  

  $ cat > $TESTTMP/checkeditform.sh <<EOF
  > env | grep HGEDITFORM
  > true
  > EOF
  $ HGEDITOR="sh $TESTTMP/checkeditform.sh" hg rebase --dest 7 --source 5 -e
  rebasing 5:361a99976cc9 "F"
  HGEDITFORM=rebase.merge
  rebasing 8:326cfedc031c "I" (tip)
  HGEDITFORM=rebase.normal
  saved backup bundle to $TESTTMP/a3/c4/.hg/strip-backup/361a99976cc9-35e980d0-backup.hg (glob)