tests/failfilemerge.py

match: drop unnecessary wrapping of regex in group

It seems the regexes have been wrapped in an unnamed group since
b6c42714d900 (Add locate command., 2005-07-05). In that commit, the
grouping was needed because there was a "head" ('^') added before the
group and a "tail" (os.sep) added after it. It seems the head was
moved inside the group in 1c0c413cccdd (Get add and locate to use new
repo and dirstate walk code., 2005-07-18) and the tail was moved
inside the group in 89985a1b3427 (Clean up walk and changes code to
use normalised names properly., 2005-07-31), So it seems to me that
we've carried around the unnecessary group for 13 years. This patch
removes it.

Differential Revision: https://phab.mercurial-scm.org/D5352

# extension to emulate interrupting filemerge._filemerge

from __future__ import absolute_import

from mercurial import (
    error,
    extensions,
    filemerge,
)

def failfilemerge(filemergefn,
                  premerge, repo, wctx, 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)