tests/test-websub.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 serve

  $ hg init test
  $ cd test

  $ cat > .hg/hgrc <<EOF
  > [extensions]
  > # this is only necessary to check that the mapping from
  > # interhg to websub works
  > interhg =
  > 
  > [websub]
  > issues = s|Issue(\d+)|<a href="http://bts.example.org/issue\1">Issue\1</a>|
  > 
  > [interhg]
  > # check that we maintain some interhg backwards compatibility...
  > # yes, 'x' is a weird delimiter...
  > markbugs = sxbugx<i class="\x">bug</i>x
  > EOF

  $ touch foo
  $ hg add foo
  $ hg commit -d '1 0' -m 'Issue123: fixed the bug!'

  $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS

log

  $ get-with-headers.py localhost:$HGPORT "rev/tip" | grep bts
  <div class="description"><a href="http://bts.example.org/issue123">Issue123</a>: fixed the <i class="x">bug</i>!</div>
errors

  $ cat errors.log

  $ cd ..