Make EventFormatVersions an enum

synapse/api/room_versions.py

@@ -11,13 +11,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
+from enum import Enum
 from typing import Callable, Dict, Optional
 
 import attr
 
 
-class EventFormatVersions:
+class EventFormatVersions(Enum):
     """This is an internal enum for tracking the version of the event format,
     independently of the room version.
 
@@ -57,7 +57,7 @@ class RoomVersion:
 
     identifier: str  # the identifier for this version
     disposition: str  # one of the RoomDispositions
-    event_format: int  # one of the EventFormatVersions
+    event_format: EventFormatVersions  # one of the EventFormatVersions
     state_res: int  # one of the StateResolutionVersions
     enforce_key_validity: bool
 

synapse/events/__init__.py

@@ -293,7 +293,7 @@ class _EventInternalMetadata:
 class EventBase(metaclass=abc.ABCMeta):
     @property
     @abc.abstractmethod
-    def format_version(self) -> int:
+    def format_version(self) -> EventFormatVersions:
         """The EventFormatVersion implemented by this event"""
         ...
 
@@ -584,7 +584,7 @@ class FrozenEventV3(FrozenEventV2):
 
 
 def _event_type_from_format_version(
-    format_version: int,
+    format_version: EventFormatVersions,
 ) -> Type[Union[FrozenEvent, FrozenEventV2, FrozenEventV3]]:
     """Returns the python type to use to construct an Event object for the
     given event format version.

synapse/storage/databases/main/events_worker.py

@@ -147,7 +147,7 @@ class _EventRow:
     stream_ordering: int
     json: str
     internal_metadata: str
-    format_version: Optional[int]
+    format_version: Optional[EventFormatVersions]
     room_version_id: Optional[str]
     rejected_reason: Optional[str]
     redactions: List[str]
@@ -1339,7 +1339,10 @@ class EventsWorkerStore(SQLBaseStore):
                     stream_ordering=row[1],
                     internal_metadata=row[2],
                     json=row[3],
-                    format_version=row[4],
+                    # TODO is this the best way to do it?
+                    format_version=(
+                        EventFormatVersions(row[4]) if row[4] is not None else None
+                    ),
                     room_version_id=row[5],
                     rejected_reason=row[6],
                     redactions=[],