wireproto: turn client capabilities into sets, sorted on the wire

Differential Revision: https://phab.mercurial-scm.org/D3169

mercurial/httppeer.py

@@ -1,502 +1,502 b''
 # httppeer.py - HTTP repository proxy classes for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # 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 errno
 import io
 import os
 import socket
 import struct
 import tempfile
 
 from .i18n import _
 from . import (
     bundle2,
     error,
     httpconnection,
     pycompat,
     statichttprepo,
     url as urlmod,
     util,
     wireproto,
 )
 
 httplib = util.httplib
 urlerr = util.urlerr
 urlreq = util.urlreq
 
 def encodevalueinheaders(value, header, limit):
     """Encode a string value into multiple HTTP headers.
 
     ``value`` will be encoded into 1 or more HTTP headers with the names
     ``header-<N>`` where ``<N>`` is an integer starting at 1. Each header
     name + value will be at most ``limit`` bytes long.
 
     Returns an iterable of 2-tuples consisting of header names and
     values as native strings.
     """
     # HTTP Headers are ASCII. Python 3 requires them to be unicodes,
     # not bytes. This function always takes bytes in as arguments.
     fmt = pycompat.strurl(header) + r'-%s'
     # Note: it is *NOT* a bug that the last bit here is a bytestring
     # and not a unicode: we're just getting the encoded length anyway,
     # and using an r-string to make it portable between Python 2 and 3
     # doesn't work because then the \r is a literal backslash-r
     # instead of a carriage return.
     valuelen = limit - len(fmt % r'000') - len(': \r\n')
     result = []
 
     n = 0
     for i in xrange(0, len(value), valuelen):
         n += 1
         result.append((fmt % str(n), pycompat.strurl(value[i:i + valuelen])))
 
     return result
 
 def _wraphttpresponse(resp):
     """Wrap an HTTPResponse with common error handlers.
 
     This ensures that any I/O from any consumer raises the appropriate
     error and messaging.
     """
     origread = resp.read
 
     class readerproxy(resp.__class__):
         def read(self, size=None):
             try:
                 return origread(size)
             except httplib.IncompleteRead as e:
                 # e.expected is an integer if length known or None otherwise.
                 if e.expected:
                     msg = _('HTTP request error (incomplete response; '
                             'expected %d bytes got %d)') % (e.expected,
                                                            len(e.partial))
                 else:
                     msg = _('HTTP request error (incomplete response)')
 
                 raise error.PeerTransportError(
                     msg,
                     hint=_('this may be an intermittent network failure; '
                            'if the error persists, consider contacting the '
                            'network or server operator'))
             except httplib.HTTPException as e:
                 raise error.PeerTransportError(
                     _('HTTP request error (%s)') % e,
                     hint=_('this may be an intermittent network failure; '
                            'if the error persists, consider contacting the '
                            'network or server operator'))
 
     resp.__class__ = readerproxy
 
 class _multifile(object):
     def __init__(self, *fileobjs):
         for f in fileobjs:
             if not util.safehasattr(f, 'length'):
                 raise ValueError(
                     '_multifile only supports file objects that '
                     'have a length but this one does not:', type(f), f)
         self._fileobjs = fileobjs
         self._index = 0
 
     @property
     def length(self):
         return sum(f.length for f in self._fileobjs)
 
     def read(self, amt=None):
         if amt <= 0:
             return ''.join(f.read() for f in self._fileobjs)
         parts = []
         while amt and self._index < len(self._fileobjs):
             parts.append(self._fileobjs[self._index].read(amt))
             got = len(parts[-1])
             if got < amt:
                 self._index += 1
             amt -= got
         return ''.join(parts)
 
     def seek(self, offset, whence=os.SEEK_SET):
         if whence != os.SEEK_SET:
             raise NotImplementedError(
                 '_multifile does not support anything other'
                 ' than os.SEEK_SET for whence on seek()')
         if offset != 0:
             raise NotImplementedError(
                 '_multifile only supports seeking to start, but that '
                 'could be fixed if you need it')
         for f in self._fileobjs:
             f.seek(0)
         self._index = 0
 
 class httppeer(wireproto.wirepeer):
     def __init__(self, ui, path, url, opener):
         self.ui = ui
         self._path = path
         self._url = url
         self._caps = None
         self._urlopener = opener
         # This is an its own attribute to facilitate extensions overriding
         # the default type.
         self._requestbuilder = urlreq.request
 
     def __del__(self):
         for h in self._urlopener.handlers:
             h.close()
             getattr(h, "close_all", lambda: None)()
 
     def _openurl(self, req):
         if (self.ui.debugflag
             and self.ui.configbool('devel', 'debug.peer-request')):
             dbg = self.ui.debug
             line = 'devel-peer-request: %s\n'
             dbg(line % '%s %s' % (req.get_method(), req.get_full_url()))
             hgargssize = None
 
             for header, value in sorted(req.header_items()):
                 if header.startswith('X-hgarg-'):
                     if hgargssize is None:
                         hgargssize = 0
                     hgargssize += len(value)
                 else:
                     dbg(line % '  %s %s' % (header, value))
 
             if hgargssize is not None:
                 dbg(line % '  %d bytes of commands arguments in headers'
                     % hgargssize)
 
             if req.has_data():
                 data = req.get_data()
                 length = getattr(data, 'length', None)
                 if length is None:
                     length = len(data)
                 dbg(line % '  %d bytes of data' % length)
 
             start = util.timer()
 
         ret = self._urlopener.open(req)
         if self.ui.configbool('devel', 'debug.peer-request'):
             dbg(line % '  finished in %.4f seconds (%s)'
                 % (util.timer() - start, ret.code))
         return ret
 
     # Begin of ipeerconnection interface.
 
     def url(self):
         return self._path
 
     def local(self):
         return None
 
     def peer(self):
         return self
 
     def canpush(self):
         return True
 
     def close(self):
         pass
 
     # End of ipeerconnection interface.
 
     # Begin of ipeercommands interface.
 
     def capabilities(self):
         # self._fetchcaps() should have been called as part of peer
         # handshake. So self._caps should always be set.
         assert self._caps is not None
         return self._caps
 
     # End of ipeercommands interface.
 
     # look up capabilities only when needed
 
     def _fetchcaps(self):
         self._caps = set(self._call('capabilities').split())
 
     def _callstream(self, cmd, _compressible=False, **args):
         args = pycompat.byteskwargs(args)
         if cmd == 'pushkey':
             args['data'] = ''
         data = args.pop('data', None)
         headers = args.pop('headers', {})
 
         self.ui.debug("sending %s command\n" % cmd)
         q = [('cmd', cmd)]
         headersize = 0
         varyheaders = []
         # Important: don't use self.capable() here or else you end up
         # with infinite recursion when trying to look up capabilities
         # for the first time.
         postargsok = self._caps is not None and 'httppostargs' in self._caps
 
         # Send arguments via POST.
         if postargsok and args:
             strargs = urlreq.urlencode(sorted(args.items()))
             if not data:
                 data = strargs
             else:
                 if isinstance(data, bytes):
                     i = io.BytesIO(data)
                     i.length = len(data)
                     data = i
                 argsio = io.BytesIO(strargs)
                 argsio.length = len(strargs)
                 data = _multifile(argsio, data)
             headers[r'X-HgArgs-Post'] = len(strargs)
         elif args:
             # Calling self.capable() can infinite loop if we are calling
             # "capabilities". But that command should never accept wire
             # protocol arguments. So this should never happen.
             assert cmd != 'capabilities'
             httpheader = self.capable('httpheader')
             if httpheader:
                 headersize = int(httpheader.split(',', 1)[0])
 
             # Send arguments via HTTP headers.
             if headersize > 0:
                 # The headers can typically carry more data than the URL.
                 encargs = urlreq.urlencode(sorted(args.items()))
                 for header, value in encodevalueinheaders(encargs, 'X-HgArg',
                                                           headersize):
                     headers[header] = value
                     varyheaders.append(header)
             # Send arguments via query string (Mercurial <1.9).
             else:
                 q += sorted(args.items())
 
         qs = '?%s' % urlreq.urlencode(q)
         cu = "%s%s" % (self._url, qs)
         size = 0
         if util.safehasattr(data, 'length'):
             size = data.length
         elif data is not None:
             size = len(data)
         if data is not None and r'Content-Type' not in headers:
             headers[r'Content-Type'] = r'application/mercurial-0.1'
 
         # Tell the server we accept application/mercurial-0.2 and multiple
         # compression formats if the server is capable of emitting those
         # payloads.
-        protoparams = []
+        protoparams = set()
 
         mediatypes = set()
         if self._caps is not None:
             mt = self.capable('httpmediatype')
             if mt:
-                protoparams.append('0.1')
+                protoparams.add('0.1')
                 mediatypes = set(mt.split(','))
 
         if '0.2tx' in mediatypes:
-            protoparams.append('0.2')
+            protoparams.add('0.2')
 
         if '0.2tx' in mediatypes and self.capable('compression'):
             # We /could/ compare supported compression formats and prune
             # non-mutually supported or error if nothing is mutually supported.
             # For now, send the full list to the server and have it error.
             comps = [e.wireprotosupport().name for e in
                      util.compengines.supportedwireengines(util.CLIENTROLE)]
-            protoparams.append('comp=%s' % ','.join(comps))
+            protoparams.add('comp=%s' % ','.join(comps))
 
         if protoparams:
-            protoheaders = encodevalueinheaders(' '.join(protoparams),
+            protoheaders = encodevalueinheaders(' '.join(sorted(protoparams)),
                                                 'X-HgProto',
                                                 headersize or 1024)
             for header, value in protoheaders:
                 headers[header] = value
                 varyheaders.append(header)
 
         if varyheaders:
             headers[r'Vary'] = r','.join(varyheaders)
 
         req = self._requestbuilder(pycompat.strurl(cu), data, headers)
 
         if data is not None:
             self.ui.debug("sending %d bytes\n" % size)
             req.add_unredirected_header(r'Content-Length', r'%d' % size)
         try:
             resp = self._openurl(req)
         except urlerr.httperror as inst:
             if inst.code == 401:
                 raise error.Abort(_('authorization failed'))
             raise
         except httplib.HTTPException as inst:
             self.ui.debug('http error while sending %s command\n' % cmd)
             self.ui.traceback()
             raise IOError(None, inst)
 
         # Insert error handlers for common I/O failures.
         _wraphttpresponse(resp)
 
         # record the url we got redirected to
         resp_url = pycompat.bytesurl(resp.geturl())
         if resp_url.endswith(qs):
             resp_url = resp_url[:-len(qs)]
         if self._url.rstrip('/') != resp_url.rstrip('/'):
             if not self.ui.quiet:
                 self.ui.warn(_('real URL is %s\n') % resp_url)
         self._url = resp_url
         try:
             proto = pycompat.bytesurl(resp.getheader(r'content-type', r''))
         except AttributeError:
             proto = pycompat.bytesurl(resp.headers.get(r'content-type', r''))
 
         safeurl = util.hidepassword(self._url)
         if proto.startswith('application/hg-error'):
             raise error.OutOfBandError(resp.read())
         # accept old "text/plain" and "application/hg-changegroup" for now
         if not (proto.startswith('application/mercurial-') or
                 (proto.startswith('text/plain')
                  and not resp.headers.get('content-length')) or
                 proto.startswith('application/hg-changegroup')):
             self.ui.debug("requested URL: '%s'\n" % util.hidepassword(cu))
             raise error.RepoError(
                 _("'%s' does not appear to be an hg repository:\n"
                   "---%%<--- (%s)\n%s\n---%%<---\n")
                 % (safeurl, proto or 'no content-type', resp.read(1024)))
 
         if proto.startswith('application/mercurial-'):
             try:
                 version = proto.split('-', 1)[1]
                 version_info = tuple([int(n) for n in version.split('.')])
             except ValueError:
                 raise error.RepoError(_("'%s' sent a broken Content-Type "
                                         "header (%s)") % (safeurl, proto))
 
             # TODO consider switching to a decompression reader that uses
             # generators.
             if version_info == (0, 1):
                 if _compressible:
                     return util.compengines['zlib'].decompressorreader(resp)
                 return resp
             elif version_info == (0, 2):
                 # application/mercurial-0.2 always identifies the compression
                 # engine in the payload header.
                 elen = struct.unpack('B', resp.read(1))[0]
                 ename = resp.read(elen)
                 engine = util.compengines.forwiretype(ename)
                 return engine.decompressorreader(resp)
             else:
                 raise error.RepoError(_("'%s' uses newer protocol %s") %
                                       (safeurl, version))
 
         if _compressible:
             return util.compengines['zlib'].decompressorreader(resp)
 
         return resp
 
     def _call(self, cmd, **args):
         fp = self._callstream(cmd, **args)
         try:
             return fp.read()
         finally:
             # if using keepalive, allow connection to be reused
             fp.close()
 
     def _callpush(self, cmd, cg, **args):
         # have to stream bundle to a temp file because we do not have
         # http 1.1 chunked transfer.
 
         types = self.capable('unbundle')
         try:
             types = types.split(',')
         except AttributeError:
             # servers older than d1b16a746db6 will send 'unbundle' as a
             # boolean capability. They only support headerless/uncompressed
             # bundles.
             types = [""]
         for x in types:
             if x in bundle2.bundletypes:
                 type = x
                 break
 
         tempname = bundle2.writebundle(self.ui, cg, None, type)
         fp = httpconnection.httpsendfile(self.ui, tempname, "rb")
         headers = {r'Content-Type': r'application/mercurial-0.1'}
 
         try:
             r = self._call(cmd, data=fp, headers=headers, **args)
             vals = r.split('\n', 1)
             if len(vals) < 2:
                 raise error.ResponseError(_("unexpected response:"), r)
             return vals
         except urlerr.httperror:
             # Catch and re-raise these so we don't try and treat them
             # like generic socket errors. They lack any values in
             # .args on Python 3 which breaks our socket.error block.
             raise
         except socket.error as err:
             if err.args[0] in (errno.ECONNRESET, errno.EPIPE):
                 raise error.Abort(_('push failed: %s') % err.args[1])
             raise error.Abort(err.args[1])
         finally:
             fp.close()
             os.unlink(tempname)
 
     def _calltwowaystream(self, cmd, fp, **args):
         fh = None
         fp_ = None
         filename = None
         try:
             # dump bundle to disk
             fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
             fh = os.fdopen(fd, r"wb")
             d = fp.read(4096)
             while d:
                 fh.write(d)
                 d = fp.read(4096)
             fh.close()
             # start http push
             fp_ = httpconnection.httpsendfile(self.ui, filename, "rb")
             headers = {r'Content-Type': r'application/mercurial-0.1'}
             return self._callstream(cmd, data=fp_, headers=headers, **args)
         finally:
             if fp_ is not None:
                 fp_.close()
             if fh is not None:
                 fh.close()
                 os.unlink(filename)
 
     def _callcompressable(self, cmd, **args):
         return self._callstream(cmd, _compressible=True, **args)
 
     def _abort(self, exception):
         raise exception
 
 def makepeer(ui, path):
     u = util.url(path)
     if u.query or u.fragment:
         raise error.Abort(_('unsupported URL component: "%s"') %
                           (u.query or u.fragment))
 
     # urllib cannot handle URLs with embedded user or passwd.
     url, authinfo = u.authinfo()
     ui.debug('using %s\n' % url)
 
     opener = urlmod.opener(ui, authinfo)
 
     return httppeer(ui, path, url, opener)
 
 def instance(ui, path, create):
     if create:
         raise error.Abort(_('cannot create new http repository'))
     try:
         if path.startswith('https:') and not urlmod.has_https:
             raise error.Abort(_('Python support for SSL and HTTPS '
                                 'is not installed'))
 
         inst = makepeer(ui, path)
         inst._fetchcaps()
 
         return inst
     except error.RepoError as httpexception:
         try:
             r = statichttprepo.instance(ui, "static-" + path, create)
             ui.note(_('(falling back to static-http)\n'))
             return r
         except error.RepoError:
             raise httpexception # use the original http RepoError instead

mercurial/sshpeer.py

@@ -1,634 +1,635 b''
 # sshpeer.py - ssh repository proxy class for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 #
 # 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 re
 import uuid
 
 from .i18n import _
 from . import (
     error,
     pycompat,
     util,
     wireproto,
     wireprotoserver,
     wireprototypes,
 )
 from .utils import (
     procutil,
 )
 
 def _serverquote(s):
     """quote a string for the remote shell ... which we assume is sh"""
     if not s:
         return s
     if re.match('[a-zA-Z0-9@%_+=:,./-]*$', s):
         return s
     return "'%s'" % s.replace("'", "'\\''")
 
 def _forwardoutput(ui, pipe):
     """display all data currently available on pipe as remote output.
 
     This is non blocking."""
     if pipe:
         s = procutil.readpipe(pipe)
         if s:
             for l in s.splitlines():
                 ui.status(_("remote: "), l, '\n')
 
 class doublepipe(object):
     """Operate a side-channel pipe in addition of a main one
 
     The side-channel pipe contains server output to be forwarded to the user
     input. The double pipe will behave as the "main" pipe, but will ensure the
     content of the "side" pipe is properly processed while we wait for blocking
     call on the "main" pipe.
 
     If large amounts of data are read from "main", the forward will cease after
     the first bytes start to appear. This simplifies the implementation
     without affecting actual output of sshpeer too much as we rarely issue
     large read for data not yet emitted by the server.
 
     The main pipe is expected to be a 'bufferedinputpipe' from the util module
     that handle all the os specific bits. This class lives in this module
     because it focus on behavior specific to the ssh protocol."""
 
     def __init__(self, ui, main, side):
         self._ui = ui
         self._main = main
         self._side = side
 
     def _wait(self):
         """wait until some data are available on main or side
 
         return a pair of boolean (ismainready, issideready)
 
         (This will only wait for data if the setup is supported by `util.poll`)
         """
         if (isinstance(self._main, util.bufferedinputpipe) and
             self._main.hasbuffer):
             # Main has data. Assume side is worth poking at.
             return True, True
 
         fds = [self._main.fileno(), self._side.fileno()]
         try:
             act = util.poll(fds)
         except NotImplementedError:
             # non supported yet case, assume all have data.
             act = fds
         return (self._main.fileno() in act, self._side.fileno() in act)
 
     def write(self, data):
         return self._call('write', data)
 
     def read(self, size):
         r = self._call('read', size)
         if size != 0 and not r:
             # We've observed a condition that indicates the
             # stdout closed unexpectedly. Check stderr one
             # more time and snag anything that's there before
             # letting anyone know the main part of the pipe
             # closed prematurely.
             _forwardoutput(self._ui, self._side)
         return r
 
     def readline(self):
         return self._call('readline')
 
     def _call(self, methname, data=None):
         """call <methname> on "main", forward output of "side" while blocking
         """
         # data can be '' or 0
         if (data is not None and not data) or self._main.closed:
             _forwardoutput(self._ui, self._side)
             return ''
         while True:
             mainready, sideready = self._wait()
             if sideready:
                 _forwardoutput(self._ui, self._side)
             if mainready:
                 meth = getattr(self._main, methname)
                 if data is None:
                     return meth()
                 else:
                     return meth(data)
 
     def close(self):
         return self._main.close()
 
     def flush(self):
         return self._main.flush()
 
 def _cleanuppipes(ui, pipei, pipeo, pipee):
     """Clean up pipes used by an SSH connection."""
     if pipeo:
         pipeo.close()
     if pipei:
         pipei.close()
 
     if pipee:
         # Try to read from the err descriptor until EOF.
         try:
             for l in pipee:
                 ui.status(_('remote: '), l)
         except (IOError, ValueError):
             pass
 
         pipee.close()
 
 def _makeconnection(ui, sshcmd, args, remotecmd, path, sshenv=None):
     """Create an SSH connection to a server.
 
     Returns a tuple of (process, stdin, stdout, stderr) for the
     spawned process.
     """
     cmd = '%s %s %s' % (
         sshcmd,
         args,
         procutil.shellquote('%s -R %s serve --stdio' % (
             _serverquote(remotecmd), _serverquote(path))))
 
     ui.debug('running %s\n' % cmd)
     cmd = procutil.quotecommand(cmd)
 
     # no buffer allow the use of 'select'
     # feel free to remove buffering and select usage when we ultimately
     # move to threading.
     stdin, stdout, stderr, proc = procutil.popen4(cmd, bufsize=0, env=sshenv)
 
     return proc, stdin, stdout, stderr
 
 def _clientcapabilities():
     """Return list of capabilities of this client.
 
     Returns a list of capabilities that are supported by this client.
     """
-    protoparams = []
+    protoparams = set()
     comps = [e.wireprotosupport().name for e in
              util.compengines.supportedwireengines(util.CLIENTROLE)]
-    protoparams.append('comp=%s' % ','.join(comps))
+    protoparams.add('comp=%s' % ','.join(comps))
     return protoparams
 
 def _performhandshake(ui, stdin, stdout, stderr):
     def badresponse():
         # Flush any output on stderr.
         _forwardoutput(ui, stderr)
 
         msg = _('no suitable response from remote hg')
         hint = ui.config('ui', 'ssherrorhint')
         raise error.RepoError(msg, hint=hint)
 
     # The handshake consists of sending wire protocol commands in reverse
     # order of protocol implementation and then sniffing for a response
     # to one of them.
     #
     # Those commands (from oldest to newest) are:
     #
     # ``between``
     #   Asks for the set of revisions between a pair of revisions. Command
     #   present in all Mercurial server implementations.
     #
     # ``hello``
     #   Instructs the server to advertise its capabilities. Introduced in
     #   Mercurial 0.9.1.
     #
     # ``upgrade``
     #   Requests upgrade from default transport protocol version 1 to
     #   a newer version. Introduced in Mercurial 4.6 as an experimental
     #   feature.
     #
     # The ``between`` command is issued with a request for the null
     # range. If the remote is a Mercurial server, this request will
     # generate a specific response: ``1\n\n``. This represents the
     # wire protocol encoded value for ``\n``. We look for ``1\n\n``
     # in the output stream and know this is the response to ``between``
     # and we're at the end of our handshake reply.
     #
     # The response to the ``hello`` command will be a line with the
     # length of the value returned by that command followed by that
     # value. If the server doesn't support ``hello`` (which should be
     # rare), that line will be ``0\n``. Otherwise, the value will contain
     # RFC 822 like lines. Of these, the ``capabilities:`` line contains
     # the capabilities of the server.
     #
     # The ``upgrade`` command isn't really a command in the traditional
     # sense of version 1 of the transport because it isn't using the
     # proper mechanism for formatting insteads: instead, it just encodes
     # arguments on the line, delimited by spaces.
     #
     # The ``upgrade`` line looks like ``upgrade <token> <capabilities>``.
     # If the server doesn't support protocol upgrades, it will reply to
     # this line with ``0\n``. Otherwise, it emits an
     # ``upgraded <token> <protocol>`` line to both stdout and stderr.
     # Content immediately following this line describes additional
     # protocol and server state.
     #
     # In addition to the responses to our command requests, the server
     # may emit "banner" output on stdout. SSH servers are allowed to
     # print messages to stdout on login. Issuing commands on connection
     # allows us to flush this banner output from the server by scanning
     # for output to our well-known ``between`` command. Of course, if
     # the banner contains ``1\n\n``, this will throw off our detection.
 
     requestlog = ui.configbool('devel', 'debug.peer-request')
 
     # Generate a random token to help identify responses to version 2
     # upgrade request.
     token = pycompat.sysbytes(str(uuid.uuid4()))
     upgradecaps = [
         ('proto', wireprotoserver.SSHV2),
     ]
     upgradecaps = util.urlreq.urlencode(upgradecaps)
 
     try:
         pairsarg = '%s-%s' % ('0' * 40, '0' * 40)
         handshake = [
             'hello\n',
             'between\n',
             'pairs %d\n' % len(pairsarg),
             pairsarg,
         ]
 
         # Request upgrade to version 2 if configured.
         if ui.configbool('experimental', 'sshpeer.advertise-v2'):
             ui.debug('sending upgrade request: %s %s\n' % (token, upgradecaps))
             handshake.insert(0, 'upgrade %s %s\n' % (token, upgradecaps))
 
         if requestlog:
             ui.debug('devel-peer-request: hello\n')
         ui.debug('sending hello command\n')
         if requestlog:
             ui.debug('devel-peer-request: between\n')
             ui.debug('devel-peer-request:   pairs: %d bytes\n' % len(pairsarg))
         ui.debug('sending between command\n')
 
         stdin.write(''.join(handshake))
         stdin.flush()
     except IOError:
         badresponse()
 
     # Assume version 1 of wire protocol by default.
     protoname = wireprototypes.SSHV1
     reupgraded = re.compile(b'^upgraded %s (.*)$' % re.escape(token))
 
     lines = ['', 'dummy']
     max_noise = 500
     while lines[-1] and max_noise:
         try:
             l = stdout.readline()
             _forwardoutput(ui, stderr)
 
             # Look for reply to protocol upgrade request. It has a token
             # in it, so there should be no false positives.
             m = reupgraded.match(l)
             if m:
                 protoname = m.group(1)
                 ui.debug('protocol upgraded to %s\n' % protoname)
                 # If an upgrade was handled, the ``hello`` and ``between``
                 # requests are ignored. The next output belongs to the
                 # protocol, so stop scanning lines.
                 break
 
             # Otherwise it could be a banner, ``0\n`` response if server
             # doesn't support upgrade.
 
             if lines[-1] == '1\n' and l == '\n':
                 break
             if l:
                 ui.debug('remote: ', l)
             lines.append(l)
             max_noise -= 1
         except IOError:
             badresponse()
     else:
         badresponse()
 
     caps = set()
 
     # For version 1, we should see a ``capabilities`` line in response to the
     # ``hello`` command.
     if protoname == wireprototypes.SSHV1:
         for l in reversed(lines):
             # Look for response to ``hello`` command. Scan from the back so
             # we don't misinterpret banner output as the command reply.
             if l.startswith('capabilities:'):
                 caps.update(l[:-1].split(':')[1].split())
                 break
     elif protoname == wireprotoserver.SSHV2:
         # We see a line with number of bytes to follow and then a value
         # looking like ``capabilities: *``.
         line = stdout.readline()
         try:
             valuelen = int(line)
         except ValueError:
             badresponse()
 
         capsline = stdout.read(valuelen)
         if not capsline.startswith('capabilities: '):
             badresponse()
 
         ui.debug('remote: %s\n' % capsline)
 
         caps.update(capsline.split(':')[1].split())
         # Trailing newline.
         stdout.read(1)
 
     # Error if we couldn't find capabilities, this means:
     #
     # 1. Remote isn't a Mercurial server
     # 2. Remote is a <0.9.1 Mercurial server
     # 3. Remote is a future Mercurial server that dropped ``hello``
     #    and other attempted handshake mechanisms.
     if not caps:
         badresponse()
 
     # Flush any output on stderr before proceeding.
     _forwardoutput(ui, stderr)
 
     return protoname, caps
 
 class sshv1peer(wireproto.wirepeer):
     def __init__(self, ui, url, proc, stdin, stdout, stderr, caps,
                  autoreadstderr=True):
         """Create a peer from an existing SSH connection.
 
         ``proc`` is a handle on the underlying SSH process.
         ``stdin``, ``stdout``, and ``stderr`` are handles on the stdio
         pipes for that process.
         ``caps`` is a set of capabilities supported by the remote.
         ``autoreadstderr`` denotes whether to automatically read from
         stderr and to forward its output.
         """
         self._url = url
         self.ui = ui
         # self._subprocess is unused. Keeping a handle on the process
         # holds a reference and prevents it from being garbage collected.
         self._subprocess = proc
 
         # And we hook up our "doublepipe" wrapper to allow querying
         # stderr any time we perform I/O.
         if autoreadstderr:
             stdout = doublepipe(ui, util.bufferedinputpipe(stdout), stderr)
             stdin = doublepipe(ui, stdin, stderr)
 
         self._pipeo = stdin
         self._pipei = stdout
         self._pipee = stderr
         self._caps = caps
         self._autoreadstderr = autoreadstderr
 
     # Commands that have a "framed" response where the first line of the
     # response contains the length of that response.
     _FRAMED_COMMANDS = {
         'batch',
     }
 
     # Begin of ipeerconnection interface.
 
     def url(self):
         return self._url
 
     def local(self):
         return None
 
     def peer(self):
         return self
 
     def canpush(self):
         return True
 
     def close(self):
         pass
 
     # End of ipeerconnection interface.
 
     # Begin of ipeercommands interface.
 
     def capabilities(self):
         return self._caps
 
     # End of ipeercommands interface.
 
     def _readerr(self):
         _forwardoutput(self.ui, self._pipee)
 
     def _abort(self, exception):
         self._cleanup()
         raise exception
 
     def _cleanup(self):
         _cleanuppipes(self.ui, self._pipei, self._pipeo, self._pipee)
 
     __del__ = _cleanup
 
     def _sendrequest(self, cmd, args, framed=False):
         if (self.ui.debugflag
             and self.ui.configbool('devel', 'debug.peer-request')):
             dbg = self.ui.debug
             line = 'devel-peer-request: %s\n'
             dbg(line % cmd)
             for key, value in sorted(args.items()):
                 if not isinstance(value, dict):
                     dbg(line % '  %s: %d bytes' % (key, len(value)))
                 else:
                     for dk, dv in sorted(value.items()):
                         dbg(line % '  %s-%s: %d' % (key, dk, len(dv)))
         self.ui.debug("sending %s command\n" % cmd)
         self._pipeo.write("%s\n" % cmd)
         _func, names = wireproto.commands[cmd]
         keys = names.split()
         wireargs = {}
         for k in keys:
             if k == '*':
                 wireargs['*'] = args
                 break
             else:
                 wireargs[k] = args[k]
                 del args[k]
         for k, v in sorted(wireargs.iteritems()):
             self._pipeo.write("%s %d\n" % (k, len(v)))
             if isinstance(v, dict):
                 for dk, dv in v.iteritems():
                     self._pipeo.write("%s %d\n" % (dk, len(dv)))
                     self._pipeo.write(dv)
             else:
                 self._pipeo.write(v)
         self._pipeo.flush()
 
         # We know exactly how many bytes are in the response. So return a proxy
         # around the raw output stream that allows reading exactly this many
         # bytes. Callers then can read() without fear of overrunning the
         # response.
         if framed:
             amount = self._getamount()
             return util.cappedreader(self._pipei, amount)
 
         return self._pipei
 
     def _callstream(self, cmd, **args):
         args = pycompat.byteskwargs(args)
         return self._sendrequest(cmd, args, framed=cmd in self._FRAMED_COMMANDS)
 
     def _callcompressable(self, cmd, **args):
         args = pycompat.byteskwargs(args)
         return self._sendrequest(cmd, args, framed=cmd in self._FRAMED_COMMANDS)
 
     def _call(self, cmd, **args):
         args = pycompat.byteskwargs(args)
         return self._sendrequest(cmd, args, framed=True).read()
 
     def _callpush(self, cmd, fp, **args):
         # The server responds with an empty frame if the client should
         # continue submitting the payload.
         r = self._call(cmd, **args)
         if r:
             return '', r
 
         # The payload consists of frames with content followed by an empty
         # frame.
         for d in iter(lambda: fp.read(4096), ''):
             self._writeframed(d)
         self._writeframed("", flush=True)
 
         # In case of success, there is an empty frame and a frame containing
         # the integer result (as a string).
         # In case of error, there is a non-empty frame containing the error.
         r = self._readframed()
         if r:
             return '', r
         return self._readframed(), ''
 
     def _calltwowaystream(self, cmd, fp, **args):
         # The server responds with an empty frame if the client should
         # continue submitting the payload.
         r = self._call(cmd, **args)
         if r:
             # XXX needs to be made better
             raise error.Abort(_('unexpected remote reply: %s') % r)
 
         # The payload consists of frames with content followed by an empty
         # frame.
         for d in iter(lambda: fp.read(4096), ''):
             self._writeframed(d)
         self._writeframed("", flush=True)
 
         return self._pipei
 
     def _getamount(self):
         l = self._pipei.readline()
         if l == '\n':
             if self._autoreadstderr:
                 self._readerr()
             msg = _('check previous remote output')
             self._abort(error.OutOfBandError(hint=msg))
         if self._autoreadstderr:
             self._readerr()
         try:
             return int(l)
         except ValueError:
             self._abort(error.ResponseError(_("unexpected response:"), l))
 
     def _readframed(self):
         size = self._getamount()
         if not size:
             return b''
 
         return self._pipei.read(size)
 
     def _writeframed(self, data, flush=False):
         self._pipeo.write("%d\n" % len(data))
         if data:
             self._pipeo.write(data)
         if flush:
             self._pipeo.flush()
         if self._autoreadstderr:
             self._readerr()
 
 class sshv2peer(sshv1peer):
     """A peer that speakers version 2 of the transport protocol."""
     # Currently version 2 is identical to version 1 post handshake.
     # And handshake is performed before the peer is instantiated. So
     # we need no custom code.
 
 def makepeer(ui, path, proc, stdin, stdout, stderr, autoreadstderr=True):
     """Make a peer instance from existing pipes.
 
     ``path`` and ``proc`` are stored on the eventual peer instance and may
     not be used for anything meaningful.
 
     ``stdin``, ``stdout``, and ``stderr`` are the pipes connected to the
     SSH server's stdio handles.
 
     This function is factored out to allow creating peers that don't
     actually spawn a new process. It is useful for starting SSH protocol
     servers and clients via non-standard means, which can be useful for
     testing.
     """
     try:
         protoname, caps = _performhandshake(ui, stdin, stdout, stderr)
     except Exception:
         _cleanuppipes(ui, stdout, stdin, stderr)
         raise
 
     if protoname == wireprototypes.SSHV1:
         return sshv1peer(ui, path, proc, stdin, stdout, stderr, caps,
                          autoreadstderr=autoreadstderr)
     elif protoname == wireprototypes.SSHV2:
         return sshv2peer(ui, path, proc, stdin, stdout, stderr, caps,
                          autoreadstderr=autoreadstderr)
     else:
         _cleanuppipes(ui, stdout, stdin, stderr)
         raise error.RepoError(_('unknown version of SSH protocol: %s') %
                               protoname)
 
 def instance(ui, path, create):
     """Create an SSH peer.
 
     The returned object conforms to the ``wireproto.wirepeer`` interface.
     """
     u = util.url(path, parsequery=False, parsefragment=False)
     if u.scheme != 'ssh' or not u.host or u.path is None:
         raise error.RepoError(_("couldn't parse location %s") % path)
 
     util.checksafessh(path)
 
     if u.passwd is not None:
         raise error.RepoError(_('password in URL not supported'))
 
     sshcmd = ui.config('ui', 'ssh')
     remotecmd = ui.config('ui', 'remotecmd')
     sshaddenv = dict(ui.configitems('sshenv'))
     sshenv = procutil.shellenviron(sshaddenv)
     remotepath = u.path or '.'
 
     args = procutil.sshargs(sshcmd, u.host, u.user, u.port)
 
     if create:
         cmd = '%s %s %s' % (sshcmd, args,
             procutil.shellquote('%s init %s' %
                 (_serverquote(remotecmd), _serverquote(remotepath))))
         ui.debug('running %s\n' % cmd)
         res = ui.system(cmd, blockedtag='sshpeer', environ=sshenv)
         if res != 0:
             raise error.RepoError(_('could not create remote repo'))
 
     proc, stdin, stdout, stderr = _makeconnection(ui, sshcmd, args, remotecmd,
                                                   remotepath, sshenv)
 
     peer = makepeer(ui, path, proc, stdin, stdout, stderr)
 
     # Finally, if supported by the server, notify it about our own
     # capabilities.
     if 'protocaps' in peer.capabilities():
         try:
-            peer._call("protocaps", caps=' '.join(_clientcapabilities()))
+            peer._call("protocaps",
+                       caps=' '.join(sorted(_clientcapabilities())))
         except IOError:
             peer._cleanup()
             raise error.RepoError(_('capability exchange failed'))
 
     return peer