diff --git a/mercurial/error.py b/mercurial/error.py
--- a/mercurial/error.py
+++ b/mercurial/error.py
@@ -308,3 +308,14 @@
 class InMemoryMergeConflictsError(Exception):
     """Exception raised when merge conflicts arose during an in-memory merge."""
     __bytes__ = _tobytes
+
+class WireprotoCommandError(Exception):
+    """Represents an error during execution of a wire protocol command.
+
+    Should only be thrown by wire protocol version 2 commands.
+
+    The error is a formatter string and an optional iterable of arguments.
+    """
+    def __init__(self, message, args=None):
+        self.message = message
+        self.messageargs = args
diff --git a/mercurial/help/internals/wireprotocolrpc.txt b/mercurial/help/internals/wireprotocolrpc.txt
--- a/mercurial/help/internals/wireprotocolrpc.txt
+++ b/mercurial/help/internals/wireprotocolrpc.txt
@@ -514,3 +514,6 @@
    message
       (array of maps) A message describing the error. The message uses the
       same format as those in the ``Human Output Side-Channel`` frame.
+
+TODO formalize when error frames can be seen and how errors can be
+recognized midway through a command response.
diff --git a/mercurial/wireprotoframing.py b/mercurial/wireprotoframing.py
--- a/mercurial/wireprotoframing.py
+++ b/mercurial/wireprotoframing.py
@@ -388,16 +388,14 @@
 
 def createbytesresponseframesfromgen(stream, requestid, gen,
                                      maxframesize=DEFAULT_MAX_FRAME_SIZE):
-    overall = b''.join(cborutil.streamencode({b'status': b'ok'}))
+    """Generator of frames from a generator of byte chunks.
 
-    yield stream.makeframe(requestid=requestid,
-                           typeid=FRAME_TYPE_COMMAND_RESPONSE,
-                           flags=FLAG_COMMAND_RESPONSE_CONTINUATION,
-                           payload=overall)
-
+    This assumes that another frame will follow whatever this emits. i.e.
+    this always emits the continuation flag and never emits the end-of-stream
+    flag.
+    """
     cb = util.chunkbuffer(gen)
-
-    flags = 0
+    flags = FLAG_COMMAND_RESPONSE_CONTINUATION
 
     while True:
         chunk = cb.read(maxframesize)
@@ -411,12 +409,20 @@
 
         flags |= FLAG_COMMAND_RESPONSE_CONTINUATION
 
-    flags ^= FLAG_COMMAND_RESPONSE_CONTINUATION
-    flags |= FLAG_COMMAND_RESPONSE_EOS
-    yield stream.makeframe(requestid=requestid,
-                           typeid=FRAME_TYPE_COMMAND_RESPONSE,
-                           flags=flags,
-                           payload=b'')
+def createcommandresponseokframe(stream, requestid):
+    overall = b''.join(cborutil.streamencode({b'status': b'ok'}))
+
+    return stream.makeframe(requestid=requestid,
+                            typeid=FRAME_TYPE_COMMAND_RESPONSE,
+                            flags=FLAG_COMMAND_RESPONSE_CONTINUATION,
+                            payload=overall)
+
+def createcommandresponseeosframe(stream, requestid):
+    """Create an empty payload frame representing command end-of-stream."""
+    return stream.makeframe(requestid=requestid,
+                            typeid=FRAME_TYPE_COMMAND_RESPONSE,
+                            flags=FLAG_COMMAND_RESPONSE_EOS,
+                            payload=b'')
 
 def createcommanderrorresponse(stream, requestid, message, args=None):
     # TODO should this be using a list of {'msg': ..., 'args': {}} so atom
@@ -686,14 +692,69 @@
                 'framegen': result,
             }
 
-    def oncommandresponsereadygen(self, stream, requestid, gen):
-        """Signal that a bytes response is ready, with data as a generator."""
+    def oncommandresponsereadyobjects(self, stream, requestid, objs):
+        """Signal that objects are ready to be sent to the client.
+
+        ``objs`` is an iterable of objects (typically a generator) that will
+        be encoded via CBOR and added to frames, which will be sent to the
+        client.
+        """
         ensureserverstream(stream)
 
+        # We need to take care over exception handling. Uncaught exceptions
+        # when generating frames could lead to premature end of the frame
+        # stream and the possibility of the server or client process getting
+        # in a bad state.
+        #
+        # Keep in mind that if ``objs`` is a generator, advancing it could
+        # raise exceptions that originated in e.g. wire protocol command
+        # functions. That is why we differentiate between exceptions raised
+        # when iterating versus other exceptions that occur.
+        #
+        # In all cases, when the function finishes, the request is fully
+        # handled and no new frames for it should be seen.
+
         def sendframes():
-            for frame in createbytesresponseframesfromgen(stream, requestid,
-                                                          gen):
-                yield frame
+            emitted = False
+            while True:
+                try:
+                    o = next(objs)
+                except StopIteration:
+                    if emitted:
+                        yield createcommandresponseeosframe(stream, requestid)
+                    break
+
+                except error.WireprotoCommandError as e:
+                    for frame in createcommanderrorresponse(
+                        stream, requestid, e.message, e.messageargs):
+                        yield frame
+                    break
+
+                except Exception as e:
+                    for frame in createerrorframe(stream, requestid,
+                                                  '%s' % e,
+                                                  errtype='server'):
+                        yield frame
+
+                    break
+
+                try:
+                    if not emitted:
+                        yield createcommandresponseokframe(stream, requestid)
+                        emitted = True
+
+                    # TODO buffer chunks so emitted frame payloads can be
+                    # larger.
+                    for frame in createbytesresponseframesfromgen(
+                        stream, requestid, cborutil.streamencode(o)):
+                        yield frame
+                except Exception as e:
+                    for frame in createerrorframe(stream, requestid,
+                                                  '%s' % e,
+                                                  errtype='server'):
+                        yield frame
+
+                    break
 
             self._activecommands.remove(requestid)
 
diff --git a/mercurial/wireprototypes.py b/mercurial/wireprototypes.py
--- a/mercurial/wireprototypes.py
+++ b/mercurial/wireprototypes.py
@@ -106,27 +106,6 @@
     def __init__(self, gen=None):
         self.gen = gen
 
-class cborresponse(object):
-    """Encode the response value as CBOR."""
-    def __init__(self, v):
-        self.value = v
-
-class v2errorresponse(object):
-    """Represents a command error for version 2 transports."""
-    def __init__(self, message, args=None):
-        self.message = message
-        self.args = args
-
-class v2streamingresponse(object):
-    """A response whose data is supplied by a generator.
-
-    The generator can either consist of data structures to CBOR
-    encode or a stream of already-encoded bytes.
-    """
-    def __init__(self, gen, compressible=True):
-        self.gen = gen
-        self.compressible = compressible
-
 # list of nodes encoding / decoding
 def decodelist(l, sep=' '):
     if l:
diff --git a/mercurial/wireprotov2peer.py b/mercurial/wireprotov2peer.py
--- a/mercurial/wireprotov2peer.py
+++ b/mercurial/wireprotov2peer.py
@@ -124,6 +124,8 @@
             else:
                 raise e
 
+            return
+
         if frame.requestid not in self._requests:
             raise error.ProgrammingError(
                 'received frame for unknown request; this is either a bug in '
diff --git a/mercurial/wireprotov2server.py b/mercurial/wireprotov2server.py
--- a/mercurial/wireprotov2server.py
+++ b/mercurial/wireprotov2server.py
@@ -19,7 +19,6 @@
     wireprototypes,
 )
 from .utils import (
-    cborutil,
     interfaceutil,
 )
 
@@ -295,31 +294,19 @@
             res.setbodybytes(_('command in frame must match command in URL'))
             return True
 
-    rsp = dispatch(repo, proto, command['command'])
-
     res.status = b'200 OK'
     res.headers[b'Content-Type'] = FRAMINGTYPE
 
-    # TODO consider adding a type to represent an iterable of values to
-    # be CBOR encoded.
-    if isinstance(rsp, wireprototypes.cborresponse):
-        # TODO consider calling oncommandresponsereadygen().
-        encoded = b''.join(cborutil.streamencode(rsp.value))
-        action, meta = reactor.oncommandresponseready(outstream,
-                                                      command['requestid'],
-                                                      encoded)
-    elif isinstance(rsp, wireprototypes.v2streamingresponse):
-        action, meta = reactor.oncommandresponsereadygen(outstream,
-                                                         command['requestid'],
-                                                         rsp.gen)
-    elif isinstance(rsp, wireprototypes.v2errorresponse):
-        action, meta = reactor.oncommanderror(outstream,
-                                              command['requestid'],
-                                              rsp.message,
-                                              rsp.args)
-    else:
+    try:
+        objs = dispatch(repo, proto, command['command'])
+
+        action, meta = reactor.oncommandresponsereadyobjects(
+            outstream, command['requestid'], objs)
+
+    except Exception as e:
         action, meta = reactor.onservererror(
-            _('unhandled response type from wire proto command'))
+            outstream, command['requestid'],
+            _('exception when invoking command: %s') % e)
 
     if action == 'sendframes':
         res.setbodygen(meta['framegen'])
@@ -430,6 +417,12 @@
     respectively. Default is to assume command requires ``push`` permissions
     because otherwise commands not declaring their permissions could modify
     a repository that is supposed to be read-only.
+
+    Wire protocol commands are generators of objects to be serialized and
+    sent to the client.
+
+    If a command raises an uncaught exception, this will be translated into
+    a command error.
     """
     transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                   if v['version'] == 2}
@@ -460,16 +453,12 @@
 
 @wireprotocommand('branchmap', permission='pull')
 def branchmapv2(repo, proto):
-    branchmap = {encoding.fromlocal(k): v
-                 for k, v in repo.branchmap().iteritems()}
-
-    return wireprototypes.cborresponse(branchmap)
+    yield {encoding.fromlocal(k): v
+           for k, v in repo.branchmap().iteritems()}
 
 @wireprotocommand('capabilities', permission='pull')
 def capabilitiesv2(repo, proto):
-    caps = _capabilitiesv2(repo, proto)
-
-    return wireprototypes.cborresponse(caps)
+    yield _capabilitiesv2(repo, proto)
 
 @wireprotocommand('heads',
                   args={
@@ -480,7 +469,7 @@
     if publiconly:
         repo = repo.filtered('immutable')
 
-    return wireprototypes.cborresponse(repo.heads())
+    yield repo.heads()
 
 @wireprotocommand('known',
                   args={
@@ -490,7 +479,7 @@
 def knownv2(repo, proto, nodes=None):
     nodes = nodes or []
     result = b''.join(b'1' if n else b'0' for n in repo.known(nodes))
-    return wireprototypes.cborresponse(result)
+    yield result
 
 @wireprotocommand('listkeys',
                   args={
@@ -502,7 +491,7 @@
     keys = {encoding.fromlocal(k): encoding.fromlocal(v)
             for k, v in keys.iteritems()}
 
-    return wireprototypes.cborresponse(keys)
+    yield keys
 
 @wireprotocommand('lookup',
                   args={
@@ -515,7 +504,7 @@
     # TODO handle exception.
     node = repo.lookup(key)
 
-    return wireprototypes.cborresponse(node)
+    yield node
 
 @wireprotocommand('pushkey',
                   args={
@@ -527,9 +516,7 @@
                   permission='push')
 def pushkeyv2(repo, proto, namespace, key, old, new):
     # TODO handle ui output redirection
-    r = repo.pushkey(encoding.tolocal(namespace),
-                     encoding.tolocal(key),
-                     encoding.tolocal(old),
-                     encoding.tolocal(new))
-
-    return wireprototypes.cborresponse(r)
+    yield repo.pushkey(encoding.tolocal(namespace),
+                       encoding.tolocal(key),
+                       encoding.tolocal(old),
+                       encoding.tolocal(new))
diff --git a/tests/test-http-api-httpv2.t b/tests/test-http-api-httpv2.t
--- a/tests/test-http-api-httpv2.t
+++ b/tests/test-http-api-httpv2.t
@@ -176,8 +176,14 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x01\x00\x02\x012\xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011\xa1FstatusBok
+  s>     \r\n
+  s>     27\r\n
+  s>     \x1f\x00\x00\x01\x00\x02\x001X\x1dcustomreadonly bytes response
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
   s>     \r\n
   s>     0\r\n
   s>     \r\n
@@ -203,13 +209,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=42; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     27\r\n
+  s>     \x1f\x00\x00\x01\x00\x02\x001
+  s>     X\x1dcustomreadonly bytes response
+  s>     \r\n
+  received frame(size=31; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     {
       b'status': b'ok'
@@ -322,8 +337,14 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x01\x00\x02\x012\xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011\xa1FstatusBok
+  s>     \r\n
+  s>     27\r\n
+  s>     \x1f\x00\x00\x01\x00\x02\x001X\x1dcustomreadonly bytes response
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
   s>     \r\n
   s>     0\r\n
   s>     \r\n
@@ -445,8 +466,14 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x01\x00\x02\x012\xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011\xa1FstatusBok
+  s>     \r\n
+  s>     27\r\n
+  s>     \x1f\x00\x00\x01\x00\x02\x001X\x1dcustomreadonly bytes response
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
   s>     \r\n
   s>     0\r\n
   s>     \r\n
@@ -478,11 +505,23 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x01\x00\x02\x012\xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011\xa1FstatusBok
+  s>     \r\n
+  s>     27\r\n
+  s>     \x1f\x00\x00\x01\x00\x02\x001X\x1dcustomreadonly bytes response
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
   s>     \r\n
-  s>     32\r\n
-  s>     *\x00\x00\x03\x00\x02\x002\xa1FstatusBokX\x1dcustomreadonly bytes response
+  s>     13\r\n
+  s>     \x0b\x00\x00\x03\x00\x02\x001\xa1FstatusBok
+  s>     \r\n
+  s>     27\r\n
+  s>     \x1f\x00\x00\x03\x00\x02\x001X\x1dcustomreadonly bytes response
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x03\x00\x02\x002
   s>     \r\n
   s>     0\r\n
   s>     \r\n
@@ -516,11 +555,23 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     33\r\n
-  s>     +\x00\x00\x03\x00\x02\x012\xa1FstatusBok\xa3Ibookmarks@Jnamespaces@Fphases@
+  s>     13\r\n
+  s>     \x0b\x00\x00\x03\x00\x02\x011\xa1FstatusBok
+  s>     \r\n
+  s>     28\r\n
+  s>      \x00\x00\x03\x00\x02\x001\xa3Ibookmarks@Jnamespaces@Fphases@
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x03\x00\x02\x002
   s>     \r\n
-  s>     14\r\n
-  s>     \x0c\x00\x00\x01\x00\x02\x002\xa1FstatusBok\xa0
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x001\xa1FstatusBok
+  s>     \r\n
+  s>     9\r\n
+  s>     \x01\x00\x00\x01\x00\x02\x001\xa0
+  s>     \r\n
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
   s>     \r\n
   s>     0\r\n
   s>     \r\n
diff --git a/tests/test-http-protocol.t b/tests/test-http-protocol.t
--- a/tests/test-http-protocol.t
+++ b/tests/test-http-protocol.t
@@ -331,13 +331,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     29\r\n
-  s>     !\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\x81T\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=33; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     1e\r\n
+  s>     \x16\x00\x00\x01\x00\x02\x001
+  s>     \x81T\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
+  s>     \r\n
+  received frame(size=22; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
   ]
diff --git a/tests/test-wireproto-command-branchmap.t b/tests/test-wireproto-command-branchmap.t
--- a/tests/test-wireproto-command-branchmap.t
+++ b/tests/test-wireproto-command-branchmap.t
@@ -59,14 +59,23 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     83\r\n
-  s>     {\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa3Gbranch1\x81T\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88Gbranch2\x81T"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfcGdefault\x82T&\x80Z\xba\x1e`\n
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
+  s>     \r\n
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     78\r\n
+  s>     p\x00\x00\x01\x00\x02\x001
+  s>     \xa3Gbranch1\x81T\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88Gbranch2\x81T"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfcGdefault\x82T&\x80Z\xba\x1e`\n
   s>     \x82\xe96a\x14\x9f#\x13\x86j"\x1a{T\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82
   s>     \r\n
-  received frame(size=123; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=112; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: {
     b'branch1': [
       b'\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88'
diff --git a/tests/test-wireproto-command-capabilities.t b/tests/test-wireproto-command-capabilities.t
--- a/tests/test-wireproto-command-capabilities.t
+++ b/tests/test-wireproto-command-capabilities.t
@@ -333,13 +333,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     1d7\r\n
-  s>     \xcf\x01\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa4Hcommands\xa7Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=463; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     1cc\r\n
+  s>     \xc4\x01\x00\x01\x00\x02\x001
+  s>     \xa4Hcommands\xa7Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1
+  s>     \r\n
+  received frame(size=452; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     {
       b'status': b'ok'
diff --git a/tests/test-wireproto-command-heads.t b/tests/test-wireproto-command-heads.t
--- a/tests/test-wireproto-command-heads.t
+++ b/tests/test-wireproto-command-heads.t
@@ -51,13 +51,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     53\r\n
-  s>     K\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\x83T\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0bT\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^T)Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=75; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     48\r\n
+  s>     @\x00\x00\x01\x00\x02\x001
+  s>     \x83T\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0bT\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^T)Dm-\xc5A\x9c_\x97Dz\x8b\xc0b\xe4\xcc2\x8b\xf2A
+  s>     \r\n
+  received frame(size=64; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     b'\x1dok\x91\xd4J\xab\xa6\xd5\xe5\x80\xbc0\xa9\x94\x850\xdb\xe0\x0b',
     b'\xaeI.6\xb0\xc83\x9f\xfa\xf3(\xd0\x0b\x85\xb4R]\xe1\x16^',
@@ -88,13 +97,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     29\r\n
-  s>     !\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\x81Tx\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=33; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     1e\r\n
+  s>     \x16\x00\x00\x01\x00\x02\x001
+  s>     \x81Tx\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc
+  s>     \r\n
+  received frame(size=22; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     b'x\xd2\xdc\xa46\xb2\xf5\xb1\x88\xac&~)\xb8\x1e\x07&m8\xfc'
   ]
diff --git a/tests/test-wireproto-command-known.t b/tests/test-wireproto-command-known.t
--- a/tests/test-wireproto-command-known.t
+++ b/tests/test-wireproto-command-known.t
@@ -43,13 +43,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     14\r\n
-  s>     \x0c\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok@
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=12; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     9\r\n
+  s>     \x01\x00\x00\x01\x00\x02\x001
+  s>     @
+  s>     \r\n
+  received frame(size=1; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: []
 
 Single known node works
@@ -76,13 +85,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     15\r\n
-  s>     \r\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBokA1
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=13; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     a\r\n
+  s>     \x02\x00\x00\x01\x00\x02\x001
+  s>     A1
+  s>     \r\n
+  received frame(size=2; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     True
   ]
@@ -111,13 +129,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     17\r\n
-  s>     \x0f\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBokC101
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=15; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     c\r\n
+  s>     \x04\x00\x00\x01\x00\x02\x001
+  s>     C101
+  s>     \r\n
+  received frame(size=4; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: [
     True,
     False,
diff --git a/tests/test-wireproto-command-listkeys.t b/tests/test-wireproto-command-listkeys.t
--- a/tests/test-wireproto-command-listkeys.t
+++ b/tests/test-wireproto-command-listkeys.t
@@ -47,13 +47,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     33\r\n
-  s>     +\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa3Ibookmarks@Jnamespaces@Fphases@
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=43; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     28\r\n
+  s>      \x00\x00\x01\x00\x02\x001
+  s>     \xa3Ibookmarks@Jnamespaces@Fphases@
+  s>     \r\n
+  received frame(size=32; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: {
     b'bookmarks': b'',
     b'namespaces': b'',
@@ -84,13 +93,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     50\r\n
-  s>     H\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa2X(be0ef73c17ade3fc89dc41701eb9fc3a91b58282A1JpublishingDTrue
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=72; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     45\r\n
+  s>     =\x00\x00\x01\x00\x02\x001
+  s>     \xa2X(be0ef73c17ade3fc89dc41701eb9fc3a91b58282A1JpublishingDTrue
+  s>     \r\n
+  received frame(size=61; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: {
     b'be0ef73c17ade3fc89dc41701eb9fc3a91b58282': b'1',
     b'publishing': b'True'
@@ -120,13 +138,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     40\r\n
-  s>     8\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa1A@X(26805aba1e600a82e93661149f2313866a221a7b
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=56; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     35\r\n
+  s>     -\x00\x00\x01\x00\x02\x001
+  s>     \xa1A@X(26805aba1e600a82e93661149f2313866a221a7b
+  s>     \r\n
+  received frame(size=45; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: {
     b'@': b'26805aba1e600a82e93661149f2313866a221a7b'
   }
diff --git a/tests/test-wireproto-command-lookup.t b/tests/test-wireproto-command-lookup.t
--- a/tests/test-wireproto-command-lookup.t
+++ b/tests/test-wireproto-command-lookup.t
@@ -43,13 +43,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     28\r\n
-  s>      \x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBokTBk\xad\xa5\xc6u\x98\xcae\x03mW\xd9\xe4\xb6K\x0c\x1c\xe7\xa0
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=32; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     1d\r\n
+  s>     \x15\x00\x00\x01\x00\x02\x001
+  s>     TBk\xad\xa5\xc6u\x98\xcae\x03mW\xd9\xe4\xb6K\x0c\x1c\xe7\xa0
+  s>     \r\n
+  received frame(size=21; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: b'Bk\xad\xa5\xc6u\x98\xcae\x03mW\xd9\xe4\xb6K\x0c\x1c\xe7\xa0'
 
   $ cat error.log
diff --git a/tests/test-wireproto-command-pushkey.t b/tests/test-wireproto-command-pushkey.t
--- a/tests/test-wireproto-command-pushkey.t
+++ b/tests/test-wireproto-command-pushkey.t
@@ -46,13 +46,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     14\r\n
-  s>     \x0c\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xf5
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=12; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     9\r\n
+  s>     \x01\x00\x00\x01\x00\x02\x001
+  s>     \xf5
+  s>     \r\n
+  received frame(size=1; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: True
 
   $ sendhttpv2peer << EOF
@@ -77,13 +86,22 @@
   s>     Content-Type: application/mercurial-exp-framing-0005\r\n
   s>     Transfer-Encoding: chunked\r\n
   s>     \r\n
-  s>     40\r\n
-  s>     8\x00\x00\x01\x00\x02\x012
-  s>     \xa1FstatusBok\xa1A@X(426bada5c67598ca65036d57d9e4b64b0c1ce7a0
+  s>     13\r\n
+  s>     \x0b\x00\x00\x01\x00\x02\x011
+  s>     \xa1FstatusBok
   s>     \r\n
-  received frame(size=56; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  s>     35\r\n
+  s>     -\x00\x00\x01\x00\x02\x001
+  s>     \xa1A@X(426bada5c67598ca65036d57d9e4b64b0c1ce7a0
+  s>     \r\n
+  received frame(size=45; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  s>     8\r\n
+  s>     \x00\x00\x00\x01\x00\x02\x002
+  s>     \r\n
   s>     0\r\n
   s>     \r\n
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
   response: {
     b'@': b'426bada5c67598ca65036d57d9e4b64b0c1ce7a0'
   }
diff --git a/tests/test-wireproto-exchangev2.t b/tests/test-wireproto-exchangev2.t
new file mode 100644
--- /dev/null
+++ b/tests/test-wireproto-exchangev2.t
@@ -0,0 +1,53 @@
+Tests for wire protocol version 2 exchange.
+Tests in this file should be folded into existing tests once protocol
+v2 has enough features that it can be enabled via #testcase in existing
+tests.
+
+  $ . $TESTDIR/wireprotohelpers.sh
+  $ enablehttpv2client
+
+  $ hg init server-simple
+  $ enablehttpv2 server-simple
+  $ cd server-simple
+  $ cat >> .hg/hgrc << EOF
+  > [phases]
+  > publish = false
+  > EOF
+  $ echo a0 > a
+  $ echo b0 > b
+  $ hg -q commit -A -m 'commit 0'
+
+  $ echo a1 > a
+  $ hg commit -m 'commit 1'
+  $ hg phase --public -r .
+  $ echo a2 > a
+  $ hg commit -m 'commit 2'
+
+  $ hg -q up -r 0
+  $ echo b1 > b
+  $ hg -q commit -m 'head 2 commit 1'
+  $ echo b2 > b
+  $ hg -q commit -m 'head 2 commit 2'
+
+  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
+  $ cat hg.pid > $DAEMON_PIDS
+
+  $ cd ..
+
+Test basic clone
+
+  $ hg --debug clone -U http://localhost:$HGPORT client-simple
+  using http://localhost:$HGPORT/
+  sending capabilities command
+  query 1; heads
+  sending 2 commands
+  sending command heads: {}
+  sending command known: {
+    'nodes': []
+  }
+  received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
+  received frame(size=43; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
+  received frame(size=11; request=3; stream=2; streamflags=; type=command-response; flags=continuation)
+  received frame(size=1; request=3; stream=2; streamflags=; type=command-response; flags=continuation)
+  received frame(size=0; request=3; stream=2; streamflags=; type=command-response; flags=eos)
diff --git a/tests/wireprotohelpers.sh b/tests/wireprotohelpers.sh
--- a/tests/wireprotohelpers.sh
+++ b/tests/wireprotohelpers.sh
@@ -26,7 +26,7 @@
 
 @wireprotov2server.wireprotocommand(b'customreadonly', permission=b'pull')
 def customreadonlyv2(repo, proto):
-    return wireprototypes.cborresponse(b'customreadonly bytes response')
+    yield b'customreadonly bytes response'
 
 @wireprotov1server.wireprotocommand(b'customreadwrite', permission=b'push')
 def customreadwrite(repo, proto):
@@ -34,7 +34,7 @@
 
 @wireprotov2server.wireprotocommand(b'customreadwrite', permission=b'push')
 def customreadwritev2(repo, proto):
-    return wireprototypes.cborresponse(b'customreadwrite bytes response')
+    yield b'customreadwrite bytes response'
 EOF
 
 cat >> $HGRCPATH << EOF