tests/test-update-branches.t

setdiscovery: fix hang when #heads>200 (issue2971)

When setting up the next sample, we always add all of the heads, regardless
of the desired max sample size. But if the number of heads exceeds this
size, then we don't add any more nodes from the still undecided set.
(This is debatable per se, and I'll investigate it, but it's how we designed
it at the moment.)

The bug was that we always added the overall heads, not the heads of the
remaining undecided set. Thus, if #heads>200 (desired sample size), we
did not make progress any longer.

# Construct the following history tree:
#
# @  5:e1bb631146ca  b1
# |
# o  4:a4fdb3b883c4 0:b608b9236435  b1
# |
# | o  3:4b57d2520816 1:44592833ba9f
# | |
# | | o  2:063f31070f65
# | |/
# | o  1:44592833ba9f
# |/
# o  0:b608b9236435

  $ hg init
  $ echo foo > foo
  $ echo zero > a
  $ hg ci -qAm0
  $ echo one > a ; hg ci -m1
  $ echo two > a ; hg ci -m2
  $ hg up -q 1
  $ echo three > a ; hg ci -qm3
  $ hg up -q 0
  $ hg branch -q b1
  $ echo four > a ; hg ci -qm4
  $ echo five > a ; hg ci -qm5

Initial repo state:

  $ hg --config 'extensions.graphlog=' \
  >    glog --template '{rev}:{node|short} {parents} {branches}\n'
  @  5:e1bb631146ca  b1
  |
  o  4:a4fdb3b883c4 0:b608b9236435  b1
  |
  | o  3:4b57d2520816 1:44592833ba9f
  | |
  | | o  2:063f31070f65
  | |/
  | o  1:44592833ba9f
  |/
  o  0:b608b9236435
  

Test helper functions:

  $ revtest () {
  >     msg=$1
  >     dirtyflag=$2   # 'clean' or 'dirty'
  >     startrev=$3
  >     targetrev=$4
  >     opt=$5
  >     hg up -qC $startrev
  >     test $dirtyflag = dirty && echo dirty > foo
  >     hg up $opt $targetrev
  >     hg parent --template 'parent={rev}\n'
  >     hg stat
  > }    

  $ norevtest () {
  >     msg=$1
  >     dirtyflag=$2   # 'clean' or 'dirty'
  >     startrev=$3
  >     opt=$4
  >     hg up -qC $startrev
  >     test $dirtyflag = dirty && echo dirty > foo
  >     hg up $opt
  >     hg parent --template 'parent={rev}\n'
  >     hg stat
  > }    

Test cases are documented in a table in the update function of merge.py.
Cases are run as shown in that table, row by row.

  $ norevtest 'none clean linear' clean 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=5

  $ norevtest 'none clean same'   clean 2
  abort: crosses branches (merge branches or update --check to force update)
  parent=2


  $ revtest 'none clean linear' clean 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ revtest 'none clean same'   clean 2 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=3

  $ revtest 'none clean cross'  clean 3 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=4


  $ revtest 'none dirty linear' dirty 1 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2
  M foo

  $ revtest 'none dirty same'   dirty 2 3
  abort: crosses branches (merge branches or use --clean to discard changes)
  parent=2
  M foo

  $ revtest 'none dirty cross'  dirty 3 4
  abort: crosses branches (merge branches or use --clean to discard changes)
  parent=3
  M foo


  $ revtest '-C dirty linear'   dirty 1 2 -C
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=2

  $ revtest '-c dirty linear'   dirty 1 2 -c
  abort: uncommitted local changes
  parent=1
  M foo

  $ norevtest '-c clean same'   clean 2 -c
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  parent=3

  $ revtest '-cC dirty linear'  dirty 1 2 -cC
  abort: cannot specify both -c/--check and -C/--clean
  parent=1
  M foo