tests/fakepatchtime.py

test: add test-transaction-rollback-on-sigpipe.t demonstrating py3 regression

When an hg push is interrupted with C-c, the remote [hg serve] command
receives SIGPIPE.

If a pretxnchangegroup hook fails, the remote hg then tries to
rollback the transaction. It begins by printing "transaction
abort!\n". This returns EPIPE, but ui.py ignores that error.

In python3 (but not python2), this "transaction abort!\n" message
stays in a buffer, so future flushes of stderr will try to print the
message again, and so those flushes will also hit EPIPE.

This test demonstrates such a case where this EPIPE causes the
transaction rollback to fail, leaving behind an abandoned transaction.

Differential Revision: https://phab.mercurial-scm.org/D9151

# extension to emulate invoking 'patch.internalpatch()' at the time
# specified by '[fakepatchtime] fakenow'

from __future__ import absolute_import

from mercurial import (
    extensions,
    patch as patchmod,
    registrar,
)
from mercurial.utils import dateutil

configtable = {}
configitem = registrar.configitem(configtable)

configitem(
    b'fakepatchtime', b'fakenow', default=None,
)


def internalpatch(
    orig,
    ui,
    repo,
    patchobj,
    strip,
    prefix=b'',
    files=None,
    eolmode=b'strict',
    similarity=0,
):
    if files is None:
        files = set()
    r = orig(
        ui,
        repo,
        patchobj,
        strip,
        prefix=prefix,
        files=files,
        eolmode=eolmode,
        similarity=similarity,
    )

    fakenow = ui.config(b'fakepatchtime', b'fakenow')
    if fakenow:
        # parsing 'fakenow' in YYYYmmddHHMM format makes comparison between
        # 'fakenow' value and 'touch -t YYYYmmddHHMM' argument easy
        fakenow = dateutil.parsedate(fakenow, [b'%Y%m%d%H%M'])[0]
        for f in files:
            repo.wvfs.utime(f, (fakenow, fakenow))

    return r


def extsetup(ui):
    extensions.wrapfunction(patchmod, 'internalpatch', internalpatch)