tests/remotefilelog-getflogheads.py

rust-revlog: fix RevlogEntry.data() for NULL_REVISION

Before this change, the pseudo-entry returned by `Revlog.get_entry` for
`NULL_REVISION` would trigger errors in application code using it.

For example, this fixes a crash spotted with changelog data
while implementing RHGitaly: `Changelog.data_for_rev(-1)` was already
returning the pseudo content as expected, e.g., for `hg log`, but
`Changelog.entry_for_rev(-1).data()` would still crash with
"corrupted revlog, hash check failed for revision -1". There is
an added test for this scenario.

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

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 = urlutil.get_unique_pull_path_obj(b'getflogheads', ui)
    peer = hg.peer(repo, {}, dest)

    try:
        flogheads = peer.x_rfl_getflogheads(path)
    finally:
        peer.close()

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