view mercurial/wireproto.py @ 13158:9e7e24052745

merge: fast-forward merge with descendant

issue2538 gives a case where a changeset is merged with its child (which is on
another branch), and to my surprise the result is a real merge with two
parents, not just a "fast forward" "merge" with only the child as parent.

That is essentially the same as issue619.

Is the existing behaviour as intended and correct?

Or is the following fix correct?

Some extra "created new head" pops up with this fix, but it seems to me like
they could be considered correct. The old branch head has been superseeded by
changes on the other branch, and when the changes on the other branch is merged
back to the branch it will introduce a new head not directly related to the
previous branch head.

(I guess the intention with existing behaviour could be to ensure that the
changesets on the branch are directly connected and that no new heads pops up
on merges.)

# wireproto.py - generic wire protocol support functions
#
# Copyright 2005-2010 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.

import urllib, tempfile, os, sys
from i18n import _
from node import bin, hex
import changegroup as changegroupmod
import repo, error, encoding, util, store
import pushkey as pushkeymod

# list of nodes encoding / decoding

def decodelist(l, sep=' '):
    return map(bin, l.split(sep))

def encodelist(l, sep=' '):
    return sep.join(map(hex, l))

# client side

class wirerepository(repo.repository):
    def lookup(self, key):
        self.requirecap('lookup', _('look up remote revision'))
        d = self._call("lookup", key=encoding.fromlocal(key))
        success, data = d[:-1].split(" ", 1)
        if int(success):
            return bin(data)
        self._abort(error.RepoError(data))

    def heads(self):
        d = self._call("heads")
        try:
            return decodelist(d[:-1])
        except:
            self._abort(error.ResponseError(_("unexpected response:"), d))

    def branchmap(self):
        d = self._call("branchmap")
        try:
            branchmap = {}
            for branchpart in d.splitlines():
                branchname, branchheads = branchpart.split(' ', 1)
                branchname = encoding.tolocal(urllib.unquote(branchname))
                branchheads = decodelist(branchheads)
                branchmap[branchname] = branchheads
            return branchmap
        except TypeError:
            self._abort(error.ResponseError(_("unexpected response:"), d))

    def branches(self, nodes):
        n = encodelist(nodes)
        d = self._call("branches", nodes=n)
        try:
            br = [tuple(decodelist(b)) for b in d.splitlines()]
            return br
        except:
            self._abort(error.ResponseError(_("unexpected response:"), d))

    def between(self, pairs):
        batch = 8 # avoid giant requests
        r = []
        for i in xrange(0, len(pairs), batch):
            n = " ".join([encodelist(p, '-') for p in pairs[i:i + batch]])
            d = self._call("between", pairs=n)
            try:
                r.extend(l and decodelist(l) or [] for l in d.splitlines())
            except:
                self._abort(error.ResponseError(_("unexpected response:"), d))
        return r

    def pushkey(self, namespace, key, old, new):
        if not self.capable('pushkey'):
            return False
        d = self._call("pushkey",
                       namespace=encoding.fromlocal(namespace),
                       key=encoding.fromlocal(key),
                       old=encoding.fromlocal(old),
                       new=encoding.fromlocal(new))
        return bool(int(d))

    def listkeys(self, namespace):
        if not self.capable('pushkey'):
            return {}
        d = self._call("listkeys", namespace=encoding.fromlocal(namespace))
        r = {}
        for l in d.splitlines():
            k, v = l.split('\t')
            r[encoding.tolocal(k)] = encoding.tolocal(v)
        return r

    def stream_out(self):
        return self._callstream('stream_out')

    def changegroup(self, nodes, kind):
        n = encodelist(nodes)
        f = self._callstream("changegroup", roots=n)
        return changegroupmod.unbundle10(self._decompress(f), 'UN')

    def changegroupsubset(self, bases, heads, kind):
        self.requirecap('changegroupsubset', _('look up remote changes'))
        bases = encodelist(bases)
        heads = encodelist(heads)
        f = self._callstream("changegroupsubset",
                             bases=bases, heads=heads)
        return changegroupmod.unbundle10(self._decompress(f), 'UN')

    def unbundle(self, cg, heads, source):
        '''Send cg (a readable file-like object representing the
        changegroup to push, typically a chunkbuffer object) to the
        remote server as a bundle. Return an integer indicating the
        result of the push (see localrepository.addchangegroup()).'''

        ret, output = self._callpush("unbundle", cg, heads=encodelist(heads))
        if ret == "":
            raise error.ResponseError(
                _('push failed:'), output)
        try:
            ret = int(ret)
        except ValueError:
            raise error.ResponseError(
                _('push failed (unexpected response):'), ret)

        for l in output.splitlines(True):
            self.ui.status(_('remote: '), l)
        return ret

# server side

class streamres(object):
    def __init__(self, gen):
        self.gen = gen

class pushres(object):
    def __init__(self, res):
        self.res = res

class pusherr(object):
    def __init__(self, res):
        self.res = res

def dispatch(repo, proto, command):
    func, spec = commands[command]
    args = proto.getargs(spec)
    return func(repo, proto, *args)

def between(repo, proto, pairs):
    pairs = [decodelist(p, '-') for p in pairs.split(" ")]
    r = []
    for b in repo.between(pairs):
        r.append(encodelist(b) + "\n")
    return "".join(r)

def branchmap(repo, proto):
    branchmap = repo.branchmap()
    heads = []
    for branch, nodes in branchmap.iteritems():
        branchname = urllib.quote(encoding.fromlocal(branch))
        branchnodes = encodelist(nodes)
        heads.append('%s %s' % (branchname, branchnodes))
    return '\n'.join(heads)

def branches(repo, proto, nodes):
    nodes = decodelist(nodes)
    r = []
    for b in repo.branches(nodes):
        r.append(encodelist(b) + "\n")
    return "".join(r)

def capabilities(repo, proto):
    caps = 'lookup changegroupsubset branchmap pushkey'.split()
    if _allowstream(repo.ui):
        requiredformats = repo.requirements & repo.supportedformats
        # if our local revlogs are just revlogv1, add 'stream' cap
        if not requiredformats - set(('revlogv1',)):
            caps.append('stream')
        # otherwise, add 'streamreqs' detailing our local revlog format
        else:
            caps.append('streamreqs=%s' % ','.join(requiredformats))
    caps.append('unbundle=%s' % ','.join(changegroupmod.bundlepriority))
    return ' '.join(caps)

def changegroup(repo, proto, roots):
    nodes = decodelist(roots)
    cg = repo.changegroup(nodes, 'serve')
    return streamres(proto.groupchunks(cg))

def changegroupsubset(repo, proto, bases, heads):
    bases = decodelist(bases)
    heads = decodelist(heads)
    cg = repo.changegroupsubset(bases, heads, 'serve')
    return streamres(proto.groupchunks(cg))

def heads(repo, proto):
    h = repo.heads()
    return encodelist(h) + "\n"

def hello(repo, proto):
    '''the hello command returns a set of lines describing various
    interesting things about the server, in an RFC822-like format.
    Currently the only one defined is "capabilities", which
    consists of a line in the form:

    capabilities: space separated list of tokens
    '''
    return "capabilities: %s\n" % (capabilities(repo, proto))

def listkeys(repo, proto, namespace):
    d = pushkeymod.list(repo, encoding.tolocal(namespace)).items()
    t = '\n'.join(['%s\t%s' % (encoding.fromlocal(k), encoding.fromlocal(v))
                   for k, v in d])
    return t

def lookup(repo, proto, key):
    try:
        r = hex(repo.lookup(encoding.tolocal(key)))
        success = 1
    except Exception, inst:
        r = str(inst)
        success = 0
    return "%s %s\n" % (success, r)

def pushkey(repo, proto, namespace, key, old, new):
    # compatibility with pre-1.8 clients which were accidentally
    # sending raw binary nodes rather than utf-8-encoded hex
    if len(new) == 20 and new.encode('string-escape') != new:
        # looks like it could be a binary node
        try:
            u = new.decode('utf-8')
            new = encoding.tolocal(new) # but cleanly decodes as UTF-8
        except UnicodeDecodeError:
            pass # binary, leave unmodified
    else:
        new = encoding.tolocal(new) # normal path

    r = pushkeymod.push(repo,
                        encoding.tolocal(namespace), encoding.tolocal(key),
                        encoding.tolocal(old), new)
    return '%s\n' % int(r)

def _allowstream(ui):
    return ui.configbool('server', 'uncompressed', True, untrusted=True)

def stream(repo, proto):
    '''If the server supports streaming clone, it advertises the "stream"
    capability with a value representing the version and flags of the repo
    it is serving. Client checks to see if it understands the format.

    The format is simple: the server writes out a line with the amount
    of files, then the total amount of bytes to be transfered (separated
    by a space). Then, for each file, the server first writes the filename
    and filesize (separated by the null character), then the file contents.
    '''

    if not _allowstream(repo.ui):
        return '1\n'

    entries = []
    total_bytes = 0
    try:
        # get consistent snapshot of repo, lock during scan
        lock = repo.lock()
        try:
            repo.ui.debug('scanning\n')
            for name, ename, size in repo.store.walk():
                entries.append((name, size))
                total_bytes += size
        finally:
            lock.release()
    except error.LockError:
        return '2\n' # error: 2

    def streamer(repo, entries, total):
        '''stream out all metadata files in repository.'''
        yield '0\n' # success
        repo.ui.debug('%d files, %d bytes to transfer\n' %
                      (len(entries), total_bytes))
        yield '%d %d\n' % (len(entries), total_bytes)
        for name, size in entries:
            repo.ui.debug('sending %s (%d bytes)\n' % (name, size))
            # partially encode name over the wire for backwards compat
            yield '%s\0%d\n' % (store.encodedir(name), size)
            for chunk in util.filechunkiter(repo.sopener(name), limit=size):
                yield chunk

    return streamres(streamer(repo, entries, total_bytes))

def unbundle(repo, proto, heads):
    their_heads = decodelist(heads)

    def check_heads():
        heads = repo.heads()
        return their_heads == ['force'] or their_heads == heads

    proto.redirect()

    # fail early if possible
    if not check_heads():
        return pusherr('unsynced changes')

    # write bundle data to temporary file because it can be big
    fd, tempname = tempfile.mkstemp(prefix='hg-unbundle-')
    fp = os.fdopen(fd, 'wb+')
    r = 0
    try:
        proto.getfile(fp)
        lock = repo.lock()
        try:
            if not check_heads():
                # someone else committed/pushed/unbundled while we
                # were transferring data
                return pusherr('unsynced changes')

            # push can proceed
            fp.seek(0)
            gen = changegroupmod.readbundle(fp, None)

            try:
                r = repo.addchangegroup(gen, 'serve', proto._client(),
                                        lock=lock)
            except util.Abort, inst:
                sys.stderr.write("abort: %s\n" % inst)
        finally:
            lock.release()
        return pushres(r)

    finally:
        fp.close()
        os.unlink(tempname)

commands = {
    'between': (between, 'pairs'),
    'branchmap': (branchmap, ''),
    'branches': (branches, 'nodes'),
    'capabilities': (capabilities, ''),
    'changegroup': (changegroup, 'roots'),
    'changegroupsubset': (changegroupsubset, 'bases heads'),
    'heads': (heads, ''),
    'hello': (hello, ''),
    'listkeys': (listkeys, 'namespace'),
    'lookup': (lookup, 'key'),
    'pushkey': (pushkey, 'namespace key old new'),
    'stream_out': (stream, ''),
    'unbundle': (unbundle, 'heads'),
}