tests/test-push-checkheads-superceed-A6.t

wrapfunction: use functools.partial if possible

Every `extensions.bind` call inserts a frame in traceback:

   ... in closure
     return func(*(args + a), **kw)

which makes traceback noisy.

The Python stdlib has a `functools.partial` which is backed by C code and
does not pollute traceback. However it does not support instancemethod and
sets `args` attribute which could be problematic for alias handling.

This patch makes `wrapfunction` use `functools.partial` if we are wrapping a
function directly exported by a module (so it's impossible to be a class or
instance method), and special handles `wrapfunction` results so alias
handling code could handle `args` just fine.

As an example, `hg rebase -s . -d . --traceback` got 6 lines removed in my
setup:

   File "hg/mercurial/dispatch.py", line 898, in _dispatch
     cmdpats, cmdoptions)
  -File "hg/mercurial/extensions.py", line 333, in closure
  -  return func(*(args + a), **kw)
   File "hg/hgext/journal.py", line 84, in runcommand
     return orig(lui, repo, cmd, fullargs, *args)
  -File "hg/mercurial/extensions.py", line 333, in closure
  -  return func(*(args + a), **kw)
   File "fb-hgext/hgext3rd/fbamend/hiddenoverride.py", line 119, in runcommand
     result = orig(lui, repo, cmd, fullargs, *args)
   File "hg/mercurial/dispatch.py", line 660, in runcommand
     ret = _runcommand(ui, options, cmd, d)
  -File "hg/mercurial/extensions.py", line 333, in closure
  -  return func(*(args + a), **kw)
   File "hg/hgext/pager.py", line 69, in pagecmd
     return orig(ui, options, cmd, cmdfunc)
   ....

Differential Revision: https://phab.mercurial-scm.org/D632

====================================
Testing head checking code: Case A-6
====================================

Mercurial checks for the introduction of new heads on push. Evolution comes
into play to detect if existing branches on the server are being replaced by
some of the new one we push.

This case is part of a series of tests checking this behavior.

Category A: simple case involving a branch being superceeded by another.
TestCase 6: multi-changeset branch, split on multiple other, (base on its own branch), same number of head

.. old-state:
..
.. * 2 branch (1-changeset, and 2-changesets)
..
.. new-state:
..
.. * 1 new branch superceeding the base of the old-2-changesets-branch,
.. * 1 new changesets on the old-1-changeset-branch superceeding the head of the other
..
.. expected-result:
..
.. * push allowed
..
.. graph-summary:
..
.. B'◔⇢ø B
..   | |
.. A | ø⇠◔ A'
..   | |/
.. C ● |
..    \|
..     ●

  $ . $TESTDIR/testlib/push-checkheads-util.sh

Test setup
----------

  $ mkdir A6
  $ cd A6
  $ setuprepos
  creating basic server and client repo
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd server
  $ mkcommit B0
  $ hg up 0
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ mkcommit C0
  created new head
  $ cd ../client
  $ hg pull
  pulling from $TESTTMP/A6/server (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit A1
  created new head
  $ hg up 'desc(C0)'
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit B1
  $ hg debugobsolete `getid "desc(A0)" ` `getid "desc(A1)"`
  obsoleted 1 changesets
  $ hg debugobsolete `getid "desc(B0)" ` `getid "desc(B1)"`
  obsoleted 1 changesets
  $ hg log -G --hidden
  @  d70a1f75a020 (draft): B1
  |
  | o  f6082bc4ffef (draft): A1
  | |
  o |  0f88766e02d6 (draft): C0
  |/
  | x  d73caddc5533 (draft): B0
  | |
  | x  8aaa48160adc (draft): A0
  |/
  o  1e4be0697311 (public): root
  

Actual testing
--------------

  $ hg push
  pushing to $TESTTMP/A6/server (glob)
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files (+1 heads)
  2 new obsolescence markers
  obsoleted 2 changesets

  $ cd ../..