view tests/test-pull-branch.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

  $ hg init t
  $ cd t
  $ echo 1 > foo
  $ hg ci -Am1 # 0
  adding foo
  $ hg branch branchA
  marked working directory as branch branchA
  (branches are permanent and global, did you want a bookmark?)
  $ echo a1 > foo
  $ hg ci -ma1 # 1

  $ cd ..
  $ hg init tt
  $ cd tt
  $ hg pull ../t
  pulling from ../t
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 495a0ec48aaf:50e089d141b7
  (run 'hg update' to get a working copy)
  $ hg up branchA
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd ../t
  $ echo a2 > foo
  $ hg ci -ma2 # 2

Create branch B:

  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch branchB
  marked working directory as branch branchB
  $ echo b1 > foo
  $ hg ci -mb1 # 3

  $ cd ../tt

A new branch is there

  $ hg pull -u ../t
  pulling from ../t
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files (+1 heads)
  new changesets 9f878dea0b96:5be59ce5067b
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Develop both branches:

  $ cd ../t
  $ hg up branchA
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a3 > foo
  $ hg ci -ma3 # 4
  $ hg up branchB
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b2 > foo
  $ hg ci -mb2 # 5

  $ cd ../tt

Should succeed, no new heads:

  $ hg pull -u ../t
  pulling from ../t
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets 7c8fe7e20c32:453e93fa00a5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Add a head on other branch:

  $ cd ../t
  $ hg up branchA
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a4 > foo
  $ hg ci -ma4 # 6
  $ hg up branchB
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b3.1 > foo
  $ hg ci -m b3.1 # 7
  $ hg up 5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b3.2 > foo
  $ hg ci -m b3.2 # 8
  created new head

  $ cd ../tt

Should succeed because there is only one head on our branch:

  $ hg pull -u ../t
  pulling from ../t
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files (+1 heads)
  new changesets da3a8a0161c6:b61cab8fe4e8
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cd ../t
  $ hg up -C branchA
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a5.1 > foo
  $ hg ci -ma5.1 # 9
  $ hg up 6
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a5.2 > foo
  $ hg ci -ma5.2 # 10
  created new head
  $ hg up 7
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b4.1 > foo
  $ hg ci -m b4.1 # 11
  $ hg up -C 8
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo b4.2 > foo
  $ hg ci -m b4.2 # 12

  $ cd ../tt

  $ hg pull -u ../t
  pulling from ../t
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files (+1 heads)
  new changesets 0c4d148ae29e:ecfc3f4a6fd9
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "d740e1a584e7: a5.2"
  1 other heads for branch "branchA"

Make changes on new branch on tt

  $ hg up 6
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch branchC
  marked working directory as branch branchC
  $ echo b1 > bar
  $ hg ci -Am "commit on branchC on tt"
  adding bar

Make changes on default branch on t

  $ cd ../t
  $ hg up -C default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a1 > bar
  $ hg ci -Am "commit on default on t"
  adding bar

Pull branchC from tt

  $ hg pull ../tt
  pulling from ../tt
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 7d8ffa4c0b22
  13 local changesets published
  (run 'hg heads' to see heads)

Make changes on default and branchC on tt

  $ cd ../tt
  $ hg pull ../t
  pulling from ../t
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)
  new changesets 2b94b54b6b5f
  1 local changesets published
  (run 'hg heads' to see heads)
  $ hg up -C default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a1 > bar1
  $ hg ci -Am "commit on default on tt"
  adding bar1
  $ hg up branchC
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo a1 > bar2
  $ hg ci -Am "commit on branchC on tt"
  adding bar2

Make changes on default and branchC on t

  $ cd ../t
  $ hg up default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a1 > bar3
  $ hg ci -Am "commit on default on t"
  adding bar3
  $ hg up branchC
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo a1 > bar4
  $ hg ci -Am "commit on branchC on tt"
  adding bar4

Pull from tt

  $ hg pull ../tt
  pulling from ../tt
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+2 heads)
  new changesets eed40c14b407:e634733b0309
  1 local changesets published
  (run 'hg heads .' to see heads, 'hg merge' to merge)

  $ cd ..