view tests/test-issue1877.t @ 36738:613954a17a25

setdiscovery: back out changeset 5cfdf6137af8 (issue5809)

As explained in the bug report, this commit caused a performance
regression. The problem occurs when the local repo has very many
heads. Before 5cfdf6137af8, we used to get the remote's list of heads
and if these heads mostly overlapped with the local repo's heads, we
would mark these common heads as common, which would greatly reduce
the size of the set of undecided nodes.

Note that a similar problem existed before 5cfdf6137af8: If the local
repo had very many heads and the server just had a few (or many heads
from a disjoint set), we would do the same kind of slow discovery as
we would with 5cfdf6137af8 in the case where local and remote repos
share a large set of common nodes.

For now, we just back out 5cfdf6137af8. We should improve the
discovery in the "local has many heads, remote has few heads" case,
but let's do that after backing this out.

Differential Revision: https://phab.mercurial-scm.org/D2643

https://bz.mercurial-scm.org/1877

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ hg ci -m 'a'
  $ echo b > a
  $ hg ci -m'b'
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg book main
  $ hg book
   * main                      0:cb9a9f314b8b
  $ echo c > c
  $ hg add c
  $ hg ci -m'c'
  created new head
  $ hg book
   * main                      2:d36c0562f908
  $ hg heads
  changeset:   2:d36c0562f908
  bookmark:    main
  tag:         tip
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   1:1e6c11564562
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg up 1e6c11564562
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (leaving bookmark main)
  $ hg merge main
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg book
     main                      2:d36c0562f908
  $ hg ci -m'merge'
  $ hg book
     main                      2:d36c0562f908

  $ cd ..