tests/test-rebase-legacy.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

Test rebase --continue with rebasestate written by legacy client

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > EOF

  $ hg init
  $ hg debugdrawdag <<'EOF'
  >    D H
  >    | |
  >    C G
  >    | |
  >    B F
  >    | |
  >  Z A E
  >   \|/
  >    R
  > EOF

rebasestate generated by a legacy client running "hg rebase -r B+D+E+G+H -d Z"

  $ touch .hg/last-message.txt
  $ cat > .hg/rebasestate <<EOF
  > 0000000000000000000000000000000000000000
  > f424eb6a8c01c4a0c0fba9f863f79b3eb5b4b69f
  > 0000000000000000000000000000000000000000
  > 0
  > 0
  > 0
  > 
  > 21a6c45028857f500f56ae84fbf40689c429305b:-2
  > de008c61a447fcfd93f808ef527d933a84048ce7:0000000000000000000000000000000000000000
  > c1e6b162678d07d0b204e5c8267d51b4e03b633c:0000000000000000000000000000000000000000
  > aeba276fcb7df8e10153a07ee728d5540693f5aa:-3
  > bd5548558fcf354d37613005737a143871bf3723:-3
  > d2fa1c02b2401b0e32867f26cce50818a4bd796a:0000000000000000000000000000000000000000
  > 6f7a236de6852570cd54649ab62b1012bb78abc8:0000000000000000000000000000000000000000
  > 6582e6951a9c48c236f746f186378e36f59f4928:0000000000000000000000000000000000000000
  > EOF

  $ hg rebase --continue
  rebasing 4:c1e6b162678d "B" (B)
  rebasing 8:6f7a236de685 "D" (D)
  rebasing 2:de008c61a447 "E" (E)
  rebasing 7:d2fa1c02b240 "G" (G)
  rebasing 9:6582e6951a9c "H" (H tip)
  warning: orphaned descendants detected, not stripping c1e6b162678d, de008c61a447
  saved backup bundle to $TESTTMP/.hg/strip-backup/6f7a236de685-9880a3dc-rebase.hg (glob)

  $ hg log -G -T '{rev}:{node|short} {desc}\n'
  o  11:721b8da0a708 H
  |
  o  10:9d65695ec3c2 G
  |
  o  9:21c8397a5d68 E
  |
  | o  8:fc52970345e8 D
  | |
  | o  7:eac96551b107 B
  |/
  | o  6:bd5548558fcf C
  | |
  | | o  5:aeba276fcb7d F
  | | |
  | o |  4:c1e6b162678d B
  | | |
  o | |  3:f424eb6a8c01 Z
  | | |
  +---o  2:de008c61a447 E
  | |
  | o  1:21a6c4502885 A
  |/
  o  0:b41ce7760717 R