Collect room-version variations into one place (#4969)

Collect all the things that make room-versions different to one another into
one place, so that it's easier to define new room versions.

3 files changed, 13 insertions, 18 deletions

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 9eaf2d3e18..0684778882 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -29,13 +29,7 @@ from unpaddedbase64 import decode_base64
 
 from twisted.internet import defer
 
-from synapse.api.constants import (
-    KNOWN_ROOM_VERSIONS,
-    EventTypes,
-    Membership,
-    RejectedReason,
-    RoomVersions,
-)
+from synapse.api.constants import EventTypes, Membership, RejectedReason
 from synapse.api.errors import (
     AuthError,
     CodeMessageException,
@@ -44,6 +38,7 @@ from synapse.api.errors import (
     StoreError,
     SynapseError,
 )
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
 from synapse.crypto.event_signing import compute_event_signature
 from synapse.event_auth import auth_types_for_event
 from synapse.events.validator import EventValidator
@@ -1733,7 +1728,9 @@ class FederationHandler(BaseHandler):
             # invalid, and it would fail auth checks anyway.
             raise SynapseError(400, "No create event in state")
 
-        room_version = create_event.content.get("room_version", RoomVersions.V1)
+        room_version = create_event.content.get(
+            "room_version", RoomVersions.V1.identifier,
+        )
 
         missing_auth_events = set()
         for e in itertools.chain(auth_events, state, [event]):
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 9b41c7b205..8bc7a7678a 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -22,7 +22,7 @@ from canonicaljson import encode_canonical_json, json
 from twisted.internet import defer
 from twisted.internet.defer import succeed
 
-from synapse.api.constants import EventTypes, Membership, RoomVersions
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import (
     AuthError,
     Codes,
@@ -30,6 +30,7 @@ from synapse.api.errors import (
     NotFoundError,
     SynapseError,
 )
+from synapse.api.room_versions import RoomVersions
 from synapse.api.urls import ConsentURIBuilder
 from synapse.events.utils import serialize_event
 from synapse.events.validator import EventValidator
@@ -603,7 +604,9 @@ class EventCreationHandler(object):
         """
 
         if event.is_state() and (event.type, event.state_key) == (EventTypes.Create, ""):
-            room_version = event.content.get("room_version", RoomVersions.V1)
+            room_version = event.content.get(
+                "room_version", RoomVersions.V1.identifier
+            )
         else:
             room_version = yield self.store.get_room_version(event.room_id)
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 67b15697fd..c3dcfec247 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -25,14 +25,9 @@ from six import iteritems, string_types
 
 from twisted.internet import defer
 
-from synapse.api.constants import (
-    DEFAULT_ROOM_VERSION,
-    KNOWN_ROOM_VERSIONS,
-    EventTypes,
-    JoinRules,
-    RoomCreationPreset,
-)
+from synapse.api.constants import EventTypes, JoinRules, RoomCreationPreset
 from synapse.api.errors import AuthError, Codes, NotFoundError, StoreError, SynapseError
+from synapse.api.room_versions import DEFAULT_ROOM_VERSION, KNOWN_ROOM_VERSIONS
 from synapse.storage.state import StateFilter
 from synapse.types import RoomAlias, RoomID, RoomStreamToken, StreamToken, UserID
 from synapse.util import stringutils
@@ -479,7 +474,7 @@ class RoomCreationHandler(BaseHandler):
         if ratelimit:
             yield self.ratelimit(requester)
 
-        room_version = config.get("room_version", DEFAULT_ROOM_VERSION)
+        room_version = config.get("room_version", DEFAULT_ROOM_VERSION.identifier)
         if not isinstance(room_version, string_types):
             raise SynapseError(
                 400,