tests/test-confused-revert.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

  $ hg init
  $ echo foo > a
  $ hg add a
  $ hg commit -m "1"

  $ echo bar > b
  $ hg add b
  $ hg remove a

Should show a removed and b added:

  $ hg status
  A b
  R a

  $ hg revert --all
  undeleting a
  forgetting b

Should show b unknown and a back to normal:

  $ hg status
  ? b

  $ rm b

  $ hg co -C 0
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo-a > a
  $ hg commit -m "2a"

  $ hg co -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo-b > a
  $ hg commit -m "2b"
  created new head

  $ HGMERGE=true hg merge 1
  merging a
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Should show foo-b:

  $ cat a
  foo-b

  $ echo bar > b
  $ hg add b
  $ rm a
  $ hg remove a

Should show a removed and b added:

  $ hg status
  A b
  R a

Revert should fail:

  $ hg revert
  abort: uncommitted merge with no revision specified
  (use 'hg update' or see 'hg help revert')
  [255]

Revert should be ok now:

  $ hg revert -r2 --all
  undeleting a
  forgetting b

Should show b unknown and a marked modified (merged):

  $ hg status
  M a
  ? b

Should show foo-b:

  $ cat a
  foo-b