tests/failfilemerge.py

pycompat: add bytestr wrapper which mostly acts as a Python 2 str

This allows us to handle bytes in mostly the same manner as Python 2 str,
so we can get rid of ugly s[i:i + 1] hacks:

  s = bytestr(s)
  while i < len(s):
      c = s[i]
      ...

This is the simpler version of the previous RFC patch which tried to preserve
the bytestr type if possible. New version simply drops the bytestr wrapping
so we aren't likely to pass a bytestr to a function that expects Python 3
bytes.

# extension to emulate interrupting filemerge._filemerge

from __future__ import absolute_import

from mercurial import (
    error,
    extensions,
    filemerge,
)

def failfilemerge(filemergefn,
                  premerge, repo, mynode, orig, fcd, fco, fca, labels=None):
    raise error.Abort("^C")
    return filemergefn(premerge, repo, mynode, orig, fcd, fco, fca, labels)

def extsetup(ui):
    extensions.wrapfunction(filemerge, '_filemerge',
                            failfilemerge)