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httppeer: remove support for connecting to <0.9.1 servers (BC)...
httppeer: remove support for connecting to <0.9.1 servers (BC) Previously, HTTP wire protocol clients would attempt a "capabilities" wire protocol command. If that failed, they would fall back to issuing a "between" command. The "capabilities" command was added in Mercurial 0.9.1 (released July 2006). The "between" command has been present for as long as the wire protocol has existed. So if the "between" command failed, it was safe to assume that the remote could not speak any version of the Mercurial wire protocol. The "between" fallback was added in 395a84f78736 in 2011. Before that changeset, Mercurial would *always* issue the "between" command and would issue "capabilities" if capabilities were requested. At that time, many connections would issue "capabilities" eventually, so it was decided to issue "capabilities" by default and fall back to "between" if that failed. This saved a round trip when connecting to modern servers while still preserving compatibility with legacy servers. Fast forward ~7 years. Mercurial servers supporting "capabilities" have been around for over a decade. If modern clients are connecting to <0.9.1 servers, they are getting a bad experience. They may even be getting bad data (an old server is vulnerable to numerous security issues and could have been p0wned, leading to a Mercurial repository serving backdoors or other badness). In addition, the fallback can harm experience for modern servers. If a client experiences an intermittent HTTP request failure (due to bad network, etc) and falls back to a "between" that works, it would assume an empty capability set and would attempt to communicate with the repository using a very ancient wire protocol. Auditing HTTP logs for hg.mozilla.org, I did find a handful of requests for the null range of the "between" command. However, requests can be days apart. And when I do see requests, they come in batches. Those batches seem to correlate to spikes of HTTP 500 or other server/network events. So I think these requests are fallbacks from failed "capabilities" requests and not from old clients. If you need even more evidence to discontinue support, apparently we have no test coverage for communicating with servers not supporting "capabilities." I know this because all tests pass with the "between" fallback removed. Finally, server-side support for <0.9.1 pushing (the "addchangegroup" wire protocol command along with locking-related commands) was dropped from the HTTP client in fda0867cfe03 in 2017 and the SSH client in 9f6e0e7ef828 in 2015. I think this all adds up to enough justification for removing client support for communicating with servers not supporting "capabilities." So this commit removes that fallback. Differential Revision: https://phab.mercurial-scm.org/D2001

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fancyopts.py
321 lines | 9.6 KiB | text/x-python | PythonLexer
# fancyopts.py - better command line parsing
#
# Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import functools
from .i18n import _
from . import (
error,
pycompat,
)
# Set of flags to not apply boolean negation logic on
nevernegate = {
# avoid --no-noninteractive
'noninteractive',
# These two flags are special because they cause hg to do one
# thing and then exit, and so aren't suitable for use in things
# like aliases anyway.
'help',
'version',
}
def _earlyoptarg(arg, shortlist, namelist):
"""Check if the given arg is a valid unabbreviated option
Returns (flag_str, has_embedded_value?, embedded_value, takes_value?)
>>> def opt(arg):
... return _earlyoptarg(arg, b'R:q', [b'cwd=', b'debugger'])
long form:
>>> opt(b'--cwd')
('--cwd', False, '', True)
>>> opt(b'--cwd=')
('--cwd', True, '', True)
>>> opt(b'--cwd=foo')
('--cwd', True, 'foo', True)
>>> opt(b'--debugger')
('--debugger', False, '', False)
>>> opt(b'--debugger=') # invalid but parsable
('--debugger', True, '', False)
short form:
>>> opt(b'-R')
('-R', False, '', True)
>>> opt(b'-Rfoo')
('-R', True, 'foo', True)
>>> opt(b'-q')
('-q', False, '', False)
>>> opt(b'-qfoo') # invalid but parsable
('-q', True, 'foo', False)
unknown or invalid:
>>> opt(b'--unknown')
('', False, '', False)
>>> opt(b'-u')
('', False, '', False)
>>> opt(b'-ufoo')
('', False, '', False)
>>> opt(b'--')
('', False, '', False)
>>> opt(b'-')
('', False, '', False)
>>> opt(b'-:')
('', False, '', False)
>>> opt(b'-:foo')
('', False, '', False)
"""
if arg.startswith('--'):
flag, eq, val = arg.partition('=')
if flag[2:] in namelist:
return flag, bool(eq), val, False
if flag[2:] + '=' in namelist:
return flag, bool(eq), val, True
elif arg.startswith('-') and arg != '-' and not arg.startswith('-:'):
flag, val = arg[:2], arg[2:]
i = shortlist.find(flag[1:])
if i >= 0:
return flag, bool(val), val, shortlist.startswith(':', i + 1)
return '', False, '', False
def earlygetopt(args, shortlist, namelist, gnu=False, keepsep=False):
"""Parse options like getopt, but ignores unknown options and abbreviated
forms
If gnu=False, this stops processing options as soon as a non/unknown-option
argument is encountered. Otherwise, option and non-option arguments may be
intermixed, and unknown-option arguments are taken as non-option.
If keepsep=True, '--' won't be removed from the list of arguments left.
This is useful for stripping early options from a full command arguments.
>>> def get(args, gnu=False, keepsep=False):
... return earlygetopt(args, b'R:q', [b'cwd=', b'debugger'],
... gnu=gnu, keepsep=keepsep)
default parsing rules for early options:
>>> get([b'x', b'--cwd', b'foo', b'-Rbar', b'-q', b'y'], gnu=True)
([('--cwd', 'foo'), ('-R', 'bar'), ('-q', '')], ['x', 'y'])
>>> get([b'x', b'--cwd=foo', b'y', b'-R', b'bar', b'--debugger'], gnu=True)
([('--cwd', 'foo'), ('-R', 'bar'), ('--debugger', '')], ['x', 'y'])
>>> get([b'--unknown', b'--cwd=foo', b'--', '--debugger'], gnu=True)
([('--cwd', 'foo')], ['--unknown', '--debugger'])
restricted parsing rules (early options must come first):
>>> get([b'--cwd', b'foo', b'-Rbar', b'x', b'-q', b'y'], gnu=False)
([('--cwd', 'foo'), ('-R', 'bar')], ['x', '-q', 'y'])
>>> get([b'--cwd=foo', b'x', b'y', b'-R', b'bar', b'--debugger'], gnu=False)
([('--cwd', 'foo')], ['x', 'y', '-R', 'bar', '--debugger'])
>>> get([b'--unknown', b'--cwd=foo', b'--', '--debugger'], gnu=False)
([], ['--unknown', '--cwd=foo', '--', '--debugger'])
stripping early options (without loosing '--'):
>>> get([b'x', b'-Rbar', b'--', '--debugger'], gnu=True, keepsep=True)[1]
['x', '--', '--debugger']
last argument:
>>> get([b'--cwd'])
([], ['--cwd'])
>>> get([b'--cwd=foo'])
([('--cwd', 'foo')], [])
>>> get([b'-R'])
([], ['-R'])
>>> get([b'-Rbar'])
([('-R', 'bar')], [])
>>> get([b'-q'])
([('-q', '')], [])
>>> get([b'-q', b'--'])
([('-q', '')], [])
'--' may be a value:
>>> get([b'-R', b'--', b'x'])
([('-R', '--')], ['x'])
>>> get([b'--cwd', b'--', b'x'])
([('--cwd', '--')], ['x'])
value passed to bool options:
>>> get([b'--debugger=foo', b'x'])
([], ['--debugger=foo', 'x'])
>>> get([b'-qfoo', b'x'])
([], ['-qfoo', 'x'])
short option isn't separated with '=':
>>> get([b'-R=bar'])
([('-R', '=bar')], [])
':' may be in shortlist, but shouldn't be taken as an option letter:
>>> get([b'-:', b'y'])
([], ['-:', 'y'])
'-' is a valid non-option argument:
>>> get([b'-', b'y'])
([], ['-', 'y'])
"""
parsedopts = []
parsedargs = []
pos = 0
while pos < len(args):
arg = args[pos]
if arg == '--':
pos += not keepsep
break
flag, hasval, val, takeval = _earlyoptarg(arg, shortlist, namelist)
if not hasval and takeval and pos + 1 >= len(args):
# missing last argument
break
if not flag or hasval and not takeval:
# non-option argument or -b/--bool=INVALID_VALUE
if gnu:
parsedargs.append(arg)
pos += 1
else:
break
elif hasval == takeval:
# -b/--bool or -s/--str=VALUE
parsedopts.append((flag, val))
pos += 1
else:
# -s/--str VALUE
parsedopts.append((flag, args[pos + 1]))
pos += 2
parsedargs.extend(args[pos:])
return parsedopts, parsedargs
def fancyopts(args, options, state, gnu=False, early=False, optaliases=None):
"""
read args, parse options, and store options in state
each option is a tuple of:
short option or ''
long option
default value
description
option value label(optional)
option types include:
boolean or none - option sets variable in state to true
string - parameter string is stored in state
list - parameter string is added to a list
integer - parameter strings is stored as int
function - call function with parameter
optaliases is a mapping from a canonical option name to a list of
additional long options. This exists for preserving backward compatibility
of early options. If we want to use it extensively, please consider moving
the functionality to the options table (e.g separate long options by '|'.)
non-option args are returned
"""
if optaliases is None:
optaliases = {}
namelist = []
shortlist = ''
argmap = {}
defmap = {}
negations = {}
alllong = set(o[1] for o in options)
for option in options:
if len(option) == 5:
short, name, default, comment, dummy = option
else:
short, name, default, comment = option
# convert opts to getopt format
onames = [name]
onames.extend(optaliases.get(name, []))
name = name.replace('-', '_')
argmap['-' + short] = name
for n in onames:
argmap['--' + n] = name
defmap[name] = default
# copy defaults to state
if isinstance(default, list):
state[name] = default[:]
elif callable(default):
state[name] = None
else:
state[name] = default
# does it take a parameter?
if not (default is None or default is True or default is False):
if short:
short += ':'
onames = [n + '=' for n in onames]
elif name not in nevernegate:
for n in onames:
if n.startswith('no-'):
insert = n[3:]
else:
insert = 'no-' + n
# backout (as a practical example) has both --commit and
# --no-commit options, so we don't want to allow the
# negations of those flags.
if insert not in alllong:
assert ('--' + n) not in negations
negations['--' + insert] = '--' + n
namelist.append(insert)
if short:
shortlist += short
if name:
namelist.extend(onames)
# parse arguments
if early:
parse = functools.partial(earlygetopt, gnu=gnu)
elif gnu:
parse = pycompat.gnugetoptb
else:
parse = pycompat.getoptb
opts, args = parse(args, shortlist, namelist)
# transfer result to state
for opt, val in opts:
boolval = True
negation = negations.get(opt, False)
if negation:
opt = negation
boolval = False
name = argmap[opt]
obj = defmap[name]
t = type(obj)
if callable(obj):
state[name] = defmap[name](val)
elif t is type(1):
try:
state[name] = int(val)
except ValueError:
raise error.Abort(_('invalid value %r for option %s, '
'expected int') % (val, opt))
elif t is type(''):
state[name] = val
elif t is type([]):
state[name].append(val)
elif t is type(None) or t is type(False):
state[name] = boolval
# return unparsed args
return args