tests/failfilemerge.py

transaction: turn lack of locking into a hard failure (API)

We have been warning about transactions without locks for about a year (and
three releases), third party extensions had a fair grace period to fix their
code, we are moving lack of locking to a hard failure in order to protect users
against repository corruption.

# extension to emulate interupting 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)