tests/remotefilelog-getflogheads.py

remotefilelog: reduce probability of race-condition in remotefilelog tests

ca1014ad3de4 introduced a new parameter `ensurestart` to speed up
remotefilelog background processes start. Unfortunately it seems to have
increased the possibility of race-conditions in remotefilelog tests testing
those background processes.

With `ensurestart=False`, it seems that it's more probable to enter in a race
condition with `debugwaitonprefetch` and `debugwaitonrepack` in remotefilelog
background tests. Our CI seems to have a high probability of triggering this
race condition so make it configurable to ensure tests are stable.

Differential Revision: https://phab.mercurial-scm.org/D6772

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    hg,
    registrar,
)

cmdtable = {}
command = registrar.command(cmdtable)

@command(b'getflogheads',
         [],
         b'path')
def getflogheads(ui, repo, path):
    """
    Extension printing a remotefilelog's heads

    Used for testing purpose
    """

    dest = repo.ui.expandpath(b'default')
    peer = hg.peer(repo, {}, dest)

    flogheads = peer.x_rfl_getflogheads(path)

    if flogheads:
        for head in flogheads:
            ui.write(head + b'\n')
    else:
        ui.write(_(b'EMPTY\n'))