tests/test-check-py3-compat.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

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

  $ testrepohg files 'set:(**.py)' \
  > -X hgdemandimport/demandimportpy2.py \
  > | sed 's|\\|/|g' | xargs $PYTHON contrib/check-py3-compat.py
  contrib/python-zstandard/setup.py not using absolute_import
  contrib/python-zstandard/setup_zstd.py not using absolute_import
  contrib/python-zstandard/tests/common.py not using absolute_import
  contrib/python-zstandard/tests/test_buffer_util.py not using absolute_import
  contrib/python-zstandard/tests/test_compressor.py not using absolute_import
  contrib/python-zstandard/tests/test_compressor_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_data_structures.py not using absolute_import
  contrib/python-zstandard/tests/test_data_structures_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_decompressor.py not using absolute_import
  contrib/python-zstandard/tests/test_decompressor_fuzzing.py not using absolute_import
  contrib/python-zstandard/tests/test_estimate_sizes.py not using absolute_import
  contrib/python-zstandard/tests/test_module_attributes.py not using absolute_import
  contrib/python-zstandard/tests/test_train_dictionary.py not using absolute_import
  setup.py not using absolute_import

#if py3exe
  $ testrepohg files 'set:(**.py) - grep(pygments)' \
  > -X hgdemandimport/demandimportpy2.py \
  > -X hgext/fsmonitor/pywatchman \
  > | sed 's|\\|/|g' | xargs $PYTHON3 contrib/check-py3-compat.py \
  > | sed 's/[0-9][0-9]*)$/*)/'
  hgext/convert/transport.py: error importing: <*Error> No module named 'svn.client' (error at transport.py:*) (glob)
  mercurial/cffi/bdiff.py: error importing: <ImportError> cannot import name '_bdiff' (error at bdiff.py:*)
  mercurial/cffi/bdiffbuild.py: error importing: <ImportError> No module named 'cffi' (error at bdiffbuild.py:*)
  mercurial/cffi/mpatch.py: error importing: <ImportError> cannot import name '_mpatch' (error at mpatch.py:*)
  mercurial/cffi/mpatchbuild.py: error importing: <ImportError> No module named 'cffi' (error at mpatchbuild.py:*)
  mercurial/cffi/osutilbuild.py: error importing: <ImportError> No module named 'cffi' (error at osutilbuild.py:*)
  mercurial/scmwindows.py: error importing: <*Error> No module named 'msvcrt' (error at win32.py:*) (glob)
  mercurial/win32.py: error importing: <*Error> No module named 'msvcrt' (error at win32.py:*) (glob)
  mercurial/windows.py: error importing: <*Error> No module named 'msvcrt' (error at windows.py:*) (glob)

#endif

#if py3exe py3pygments
  $ testrepohg files 'set:(**.py) and grep(pygments)' | sed 's|\\|/|g' \
  > | xargs $PYTHON3 contrib/check-py3-compat.py \
  > | sed 's/[0-9][0-9]*)$/*)/'
#endif