tests/remotefilelog-getflogheads.py

graftcopies: use _filter() for filtering out invalid copies

`graftcopies()` (formerly called `duplicatecopies()`) checked that the
copy destination existed in the working copy, but it didn't check that
copy source existed in the parent of the working copy. In
`test-graft.t` we can see that as warnings about not finding ancestors
of the copied files, and also empty commits getting created.

This patch uses the existing `_filter()` function for filtering out
invalid copies. In addition to the aforementioned types, that also
includes copies where source and destination is the same.

Differential Revision: https://phab.mercurial-scm.org/D7859

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'))