tests/remotefilelog-getflogheads.py

remotefilelog: import pruned-down remotefilelog extension from hg-experimental

This is remotefilelog as of my recent patches for compatibility with
current tip of hg, minus support for old versions of Mercurial and
some FB-specific features like their treemanifest extension and
fetching linkrev data from a patched phabricator. The file extutil.py
moved from hgext3rd to remotefilelog.

This is not yet ready to be landed, consider it a preview for
now. Planned changes include:

 * replace lz4 with zstd
 * rename some capabilities, requirements and wireproto commands to mark
   them as experimental
 * consolidate bits of shallowutil with related functions (eg readfile)

I'm certainly open to other (small) changes, but my rough mission is
to land this largely as-is so we can use it as a model of the
functionality we need going forward for lazy-fetching of file contents
from a server.

# no-check-commit because of a few foo_bar functions

Differential Revision: https://phab.mercurial-scm.org/D4782

from __future__ import absolute_import

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

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

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

    Used for testing purpose
    """

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

    flogheads = peer.getflogheads(path)

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