view tests/test-bookmarks-corner-case.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

================================
Test corner case around bookmark
================================

This test file is meant to gather test around bookmark that are specific
 enough to not find a place elsewhere.

Test bookmark/changelog race condition
======================================

The data from the bookmark file are filtered to only contains bookmark with
node known to the changelog. If the cache invalidation between these two bits
goes wrong, bookmark can be dropped.

global setup
------------

  $ cat >> $HGRCPATH << EOF
  > [ui]
  > ssh = "$PYTHON" "$TESTDIR/dummyssh"
  > [server]
  > concurrent-push-mode=check-related
  > EOF

Setup
-----

initial repository setup

  $ hg init bookrace-server
  $ cd bookrace-server
  $ echo a > a
  $ hg add a
  $ hg commit -m root
  $ echo a >> a
  $ hg bookmark book-A
  $ hg commit -m A0
  $ hg up 'desc(root)'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (leaving bookmark book-A)
  $ echo b > b
  $ hg add b
  $ hg bookmark book-B
  $ hg commit -m B0
  created new head
  $ hg up null
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  (leaving bookmark book-B)
  $ hg phase --public --rev 'all()'
  $ hg log -G
  o  changeset:   2:c79985706978
  |  bookmark:    book-B
  |  tag:         tip
  |  parent:      0:6569b5a81c7e
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     B0
  |
  | o  changeset:   1:39c28d785860
  |/   bookmark:    book-A
  |    user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     A0
  |
  o  changeset:   0:6569b5a81c7e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg book
     book-A                    1:39c28d785860
     book-B                    2:c79985706978
  $ cd ..

Add new changeset on each bookmark in distinct clones

  $ hg clone ssh://user@dummy/bookrace-server client-A
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files (+1 heads)
  new changesets 6569b5a81c7e:c79985706978
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -R client-A update book-A
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (activating bookmark book-A)
  $ echo a >> client-A/a
  $ hg -R client-A commit -m A1
  $ hg clone ssh://user@dummy/bookrace-server client-B
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 2 files (+1 heads)
  new changesets 6569b5a81c7e:c79985706978
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg -R client-B update book-B
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (activating bookmark book-B)
  $ echo b >> client-B/b
  $ hg -R client-B commit -m B1

extension to reproduce the race
-------------------------------

If two process are pushing we want to make sure the following happens:

* process A read changelog
* process B to its full push
* process A read bookmarks
* process A proceed with rest of the push

We build a server side extension for this purpose

  $ cat > bookrace.py << EOF
  > import atexit
  > import os
  > import time
  > from mercurial import bookmarks, error, extensions
  > 
  > def wait(repo):
  >     if not os.path.exists('push-A-started'):
  >         assert repo._currentlock(repo._lockref) is None
  >         assert repo._currentlock(repo._wlockref) is None
  >         repo.ui.status(b'setting raced push up\n')
  >         with open('push-A-started', 'w'):
  >             pass
  >     clock = 300
  >     while not os.path.exists('push-B-done'):
  >         clock -= 1
  >         if clock <= 0:
  >             raise error.Abort("race scenario timed out")
  >         time.sleep(0.1)
  > 
  > def reposetup(ui, repo):
  >     class racedrepo(repo.__class__):
  >         @property
  >         def _bookmarks(self):
  >             wait(self)
  >             return super(racedrepo, self)._bookmarks
  >     repo.__class__ = racedrepo
  > 
  > def e():
  >     with open('push-A-done', 'w'):
  >         pass
  > atexit.register(e)
  > EOF

Actual test
-----------

Start the raced push.

  $ cat >> bookrace-server/.hg/hgrc << EOF
  > [extensions]
  > bookrace=$TESTTMP/bookrace.py
  > EOF
  $ hg push -R client-A -r book-A >push-output.txt 2>&1 &

Wait up to 30 seconds for that push to start.

  $ clock=30
  $ while [ ! -f push-A-started ] && [ $clock -gt 0 ] ; do
  >    clock=`expr $clock - 1`
  >    sleep 1
  > done

Do the other push.

  $ cat >> bookrace-server/.hg/hgrc << EOF
  > [extensions]
  > bookrace=!
  > EOF

  $ hg push -R client-B -r book-B
  pushing to ssh://user@dummy/bookrace-server
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  updating bookmark book-B

Signal the raced put that we are done (it waits up to 30 seconds).

  $ touch push-B-done

Wait for the raced push to finish (with the remaning of the initial 30 seconds).

  $ while [ ! -f push-A-done ] && [ $clock -gt 0 ] ; do
  >    clock=`expr $clock - 1`
  >    sleep 1
  > done

Check raced push output.

  $ cat push-output.txt
  pushing to ssh://user@dummy/bookrace-server
  searching for changes
  remote has heads on branch 'default' that are not known locally: f26c3b5167d1
  remote: setting raced push up
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
  updating bookmark book-A

Check result of the push.

  $ hg -R bookrace-server log -G
  o  changeset:   4:9ce3b28c16de
  |  bookmark:    book-A
  |  tag:         tip
  |  parent:      1:39c28d785860
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     A1
  |
  | o  changeset:   3:f26c3b5167d1
  | |  bookmark:    book-B
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  summary:     B1
  | |
  | o  changeset:   2:c79985706978
  | |  parent:      0:6569b5a81c7e
  | |  user:        test
  | |  date:        Thu Jan 01 00:00:00 1970 +0000
  | |  summary:     B0
  | |
  o |  changeset:   1:39c28d785860
  |/   user:        test
  |    date:        Thu Jan 01 00:00:00 1970 +0000
  |    summary:     A0
  |
  o  changeset:   0:6569b5a81c7e
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     root
  
  $ hg -R bookrace-server book
     book-A                    4:9ce3b28c16de
     book-B                    3:f26c3b5167d1