comparison tests/test-branches.t @ 46254:c4b792fa109e

branchmap: avoid ancestor computations in absence of non-continous branches

The branchhead computation is one of the more heavy operations for
bigger repositories as it has to scan all changesets and potentially
involves the expensive computation of the ancestor sets. Redo the
computation to handle the common cases directly and use tighter
conditions for when the ancestor scan is necessary. Most importantly,
avoid it completely if the non-continous branches are processed in one
update as seen in the initial computation after a clone.

For the Mercurial repository, it gives a small 2-3% performance boost.
For the NetBSD test repository, it cuts the time in half.

Differential Revision: https://phab.mercurial-scm.org/D9631

46253:1cebad969d88

  (use --force-close-branch to close branch from a non-head changeset)
  [10]

  $ hg ci -m "branch closed" --force-close-branch
  created new head

46254:c4b792fa109e

  (use --force-close-branch to close branch from a non-head changeset)
  [10]

  $ hg ci -m "branch closed" --force-close-branch
  created new head
  $ cd ..

Test various special cases for the branchmap
--------------------------------------------

Basic fork of the same branch

  $ hg init branchmap-testing1
  $ cd branchmap-testing1
  $ hg debugbuild '@A . :base . :p1 *base /p1'
  $ hg log -G
  o    changeset:   3:71ca9a6d524e
  |\   branch:      A
  | |  tag:         tip
  | |  parent:      2:a3b807b3ff0b
  | |  parent:      1:99ba08759bc7
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:03 1970 +0000
  | |  summary:     r3
  | |
  | o  changeset:   2:a3b807b3ff0b
  | |  branch:      A
  | |  parent:      0:2ab8003a1750
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:02 1970 +0000
  | |  summary:     r2
  | |
  o |  changeset:   1:99ba08759bc7
  |/   branch:      A
  |    tag:         p1
  |    user:        debugbuilddag
  |    date:        Thu Jan 01 00:00:01 1970 +0000
  |    summary:     r1
  |
  o  changeset:   0:2ab8003a1750
     branch:      A
     tag:         base
     user:        debugbuilddag
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     r0
  
  $ hg branches
  A                              3:71ca9a6d524e
  $ hg clone -r 1 -r 2 . ../branchmap-testing1-clone
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 0 changes to 0 files (+1 heads)
  new changesets 2ab8003a1750:a3b807b3ff0b
  updating to branch A
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branchmap-testing1-clone
  $ hg pull ../branchmap-testing1
  pulling from ../branchmap-testing1
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (-1 heads)
  new changesets 71ca9a6d524e
  (run 'hg update' to get a working copy)
  $ hg branches
  A                              3:71ca9a6d524e
  $ cd ..

Switching to a different branch and back

  $ hg init branchmap-testing2
  $ cd branchmap-testing2
  $ hg debugbuild '@A . @B . @A .'
  $ hg log -G
  o  changeset:   2:9699e9f260b5
  |  branch:      A
  |  tag:         tip
  |  user:        debugbuilddag
  |  date:        Thu Jan 01 00:00:02 1970 +0000
  |  summary:     r2
  |
  o  changeset:   1:0bc7d348d965
  |  branch:      B
  |  user:        debugbuilddag
  |  date:        Thu Jan 01 00:00:01 1970 +0000
  |  summary:     r1
  |
  o  changeset:   0:2ab8003a1750
     branch:      A
     user:        debugbuilddag
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     r0
  
  $ hg branches
  A                              2:9699e9f260b5
  B                              1:0bc7d348d965 (inactive)
  $ hg clone -r 1 . ../branchmap-testing2-clone
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 0 changes to 0 files
  new changesets 2ab8003a1750:0bc7d348d965
  updating to branch B
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branchmap-testing2-clone
  $ hg pull ../branchmap-testing2
  pulling from ../branchmap-testing2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets 9699e9f260b5
  (run 'hg update' to get a working copy)
  $ hg branches
  A                              2:9699e9f260b5
  B                              1:0bc7d348d965 (inactive)
  $ cd ..

A fork on a branch switching to a different branch and back
is still collecting the fork.

  $ hg init branchmap-testing3
  $ cd branchmap-testing3
  $ hg debugbuild '@A . :base . :p1 *base @B . @A /p1'
  $ hg log -G
  o    changeset:   4:3614a1711d23
  |\   branch:      A
  | |  tag:         tip
  | |  parent:      3:e9c8abcf65aa
  | |  parent:      1:99ba08759bc7
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:04 1970 +0000
  | |  summary:     r4
  | |
  | o  changeset:   3:e9c8abcf65aa
  | |  branch:      B
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:03 1970 +0000
  | |  summary:     r3
  | |
  | o  changeset:   2:a3b807b3ff0b
  | |  branch:      A
  | |  parent:      0:2ab8003a1750
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:02 1970 +0000
  | |  summary:     r2
  | |
  o |  changeset:   1:99ba08759bc7
  |/   branch:      A
  |    tag:         p1
  |    user:        debugbuilddag
  |    date:        Thu Jan 01 00:00:01 1970 +0000
  |    summary:     r1
  |
  o  changeset:   0:2ab8003a1750
     branch:      A
     tag:         base
     user:        debugbuilddag
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     r0
  
  $ hg branches
  A                              4:3614a1711d23
  B                              3:e9c8abcf65aa (inactive)
  $ hg clone -r 1 -r 3 . ../branchmap-testing3-clone
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 0 changes to 0 files (+1 heads)
  new changesets 2ab8003a1750:e9c8abcf65aa
  updating to branch A
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branchmap-testing3-clone
  $ hg pull ../branchmap-testing3
  pulling from ../branchmap-testing3
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (-1 heads)
  new changesets 3614a1711d23
  (run 'hg update' to get a working copy)
  $ hg branches
  A                              4:3614a1711d23
  B                              3:e9c8abcf65aa (inactive)
  $ cd ..

Intermediary parents are on different branches.

  $ hg init branchmap-testing4
  $ cd branchmap-testing4
  $ hg debugbuild '@A . @B :base . @A :p1 *base @C . @A /p1'
  $ hg log -G
  o    changeset:   4:4bf67499b70a
  |\   branch:      A
  | |  tag:         tip
  | |  parent:      3:4a546028fa8f
  | |  parent:      1:0bc7d348d965
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:04 1970 +0000
  | |  summary:     r4
  | |
  | o  changeset:   3:4a546028fa8f
  | |  branch:      C
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:03 1970 +0000
  | |  summary:     r3
  | |
  | o  changeset:   2:a3b807b3ff0b
  | |  branch:      A
  | |  parent:      0:2ab8003a1750
  | |  user:        debugbuilddag
  | |  date:        Thu Jan 01 00:00:02 1970 +0000
  | |  summary:     r2
  | |
  o |  changeset:   1:0bc7d348d965
  |/   branch:      B
  |    tag:         p1
  |    user:        debugbuilddag
  |    date:        Thu Jan 01 00:00:01 1970 +0000
  |    summary:     r1
  |
  o  changeset:   0:2ab8003a1750
     branch:      A
     tag:         base
     user:        debugbuilddag
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     r0
  
  $ hg branches
  A                              4:4bf67499b70a
  C                              3:4a546028fa8f (inactive)
  B                              1:0bc7d348d965 (inactive)
  $ hg clone -r 1 -r 3 . ../branchmap-testing4-clone
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 0 changes to 0 files (+1 heads)
  new changesets 2ab8003a1750:4a546028fa8f
  updating to branch B
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd ../branchmap-testing4-clone
  $ hg pull ../branchmap-testing4
  pulling from ../branchmap-testing4
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files (-1 heads)
  new changesets 4bf67499b70a
  (run 'hg update' to get a working copy)
  $ hg branches
  A                              4:4bf67499b70a
  C                              3:4a546028fa8f (inactive)
  B                              1:0bc7d348d965 (inactive)
  $ cd ..