tests/test-docker-packaging.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

#require test-repo slow docker

  $ . "$TESTDIR/helpers-testrepo.sh"
  $ testrepohgenv

Ensure debuild doesn't run the testsuite, as that could get silly.
  $ DEB_BUILD_OPTIONS=nocheck
  $ export DEB_BUILD_OPTIONS
  $ OUTPUTDIR=`pwd`
  $ export OUTPUTDIR

  $ cd "$TESTDIR"/..
  $ make docker-debian-jessie > $OUTPUTDIR/build.log 2>&1
  $ cd $OUTPUTDIR
  $ ls *.deb
  mercurial-common_*.deb (glob)
  mercurial_*.deb (glob)

We check debian package contents with portable tools so that when
we're on non-debian machines we can still test the packages that are
built using docker.

main deb should have .so but no .py
  $ ar x mercurial_*.deb
  $ tar tf data.tar* | egrep '(localrepo|parsers)'
  ./usr/lib/python2.7/dist-packages/mercurial/parsers*.so (glob)
mercurial-common should have .py but no .so or .pyc
  $ ar x mercurial-common_*.deb
  $ tar tf data.tar* | egrep '(localrepo|parsers)'
  ./usr/lib/python2.7/dist-packages/mercurial/pure/parsers.py
  ./usr/lib/python2.7/dist-packages/mercurial/localrepo.py