effectflag: store an empty effect flag for the moment
The idea behind effect flag is to store additional information in obs-markers
about what changed between a changeset and its successor(s). It's a low-level
information that comes without guarantees.
This information can be computed a posteriori, but only if we have all
changesets locally. This is not the case with distributed workflows where you
work with several people or on several computers (eg: laptop + build server).
Storing the effect-flag as a bitfield has several advantages:
- It's compact, we are using one byte per obs-marker at most for the effect-
flag.
- It's compoundable, the obsfate log approach needs to display evolve history
that could spans several obs-markers. Computing the effect-flag between a
changeset and its grand-grand-grand-successor is simple thanks to the
bitfield.
The effect-flag design has also some limitations:
- Evolving a changeset and reverting these changes just after would lead to
two obs-markers with the same effect-flag without information that the first
and third changesets are the same.
The effect-flag current design is a trade-off between compactness and
usefulness.
Storing this information helps commands to display a more complete and
understandable evolve history. For example, obslog (an Evolve command) use it
to improve its output:
x 62206adfd571 (34302) obscache: skip updating outdated obscache...
| rewritten(parent) by Matthieu Laneuville <matthieu.laneuville@octobus...
| rewritten(content) by Boris Feld <boris.feld@octobus.net>
The effect flag is stored in obs-markers metadata while we iterate on the
information we want to store. We plan to extend the existing obsmarkers
bit-field when the effect flag design will be stabilized.
It's different from the CommitCustody concept, effect-flag are not signed and
can be forged. It's also different from the operation metadata as the command
name (for example: amend) could alter a changeset in different ways (changing
the content with hg amend, changing the description with hg amend -e, changing
the user with hg amend -U). Also it's compatible with every custom command
that writes obs-markers without needing to be updated.
The effect-flag is placed behind an experimental flag set to off by default.
Hook the saving of effect flag in create markers, but store only an empty one
for the moment, I will refine the values in effect flag in following patches.
For more information, see:
https://www.mercurial-scm.org/wiki/ChangesetEvolutionDevel#Record_types_of_operation
Differential Revision: https://phab.mercurial-scm.org/D533
#!/usr/bin/env python
from __future__ import absolute_import
"""
Small and dumb HTTP server for use in tests.
"""
import optparse
import os
import signal
import socket
import sys
from mercurial import (
server,
util,
)
httpserver = util.httpserver
OptionParser = optparse.OptionParser
if os.environ.get('HGIPV6', '0') == '1':
class simplehttpserver(httpserver.httpserver):
address_family = socket.AF_INET6
else:
simplehttpserver = httpserver.httpserver
class simplehttpservice(object):
def __init__(self, host, port):
self.address = (host, port)
def init(self):
self.httpd = simplehttpserver(
self.address, httpserver.simplehttprequesthandler)
def run(self):
self.httpd.serve_forever()
if __name__ == '__main__':
parser = OptionParser()
parser.add_option('-p', '--port', dest='port', type='int', default=8000,
help='TCP port to listen on', metavar='PORT')
parser.add_option('-H', '--host', dest='host', default='localhost',
help='hostname or IP to listen on', metavar='HOST')
parser.add_option('--pid', dest='pid',
help='file name where the PID of the server is stored')
parser.add_option('-f', '--foreground', dest='foreground',
action='store_true',
help='do not start the HTTP server in the background')
parser.add_option('--daemon-postexec', action='append')
(options, args) = parser.parse_args()
signal.signal(signal.SIGTERM, lambda x, y: sys.exit(0))
if options.foreground and options.pid:
parser.error("options --pid and --foreground are mutually exclusive")
opts = {'pid_file': options.pid,
'daemon': not options.foreground,
'daemon_postexec': options.daemon_postexec}
service = simplehttpservice(options.host, options.port)
server.runservice(opts, initfn=service.init, runfn=service.run,
runargs=[sys.executable, __file__] + sys.argv[1:])