Store room_versions in EventBase objects (#6875)

This is a bit fiddly because it all has to be done on one fell swoop:

* Wherever we create a new event, pass in the room version (and check it matches the format version)
* When we prune an event, use the room version of the unpruned event to create the pruned version.
* When we pass an event over the replication protocol, pass the room version over alongside it, and use it when deserialising the event again.

2 files changed, 19 insertions, 8 deletions

diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index 8794720101..7e23b565b9 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -18,7 +18,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
-from synapse.events import event_type_from_format_version
+from synapse.events import make_event_from_dict
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
@@ -38,6 +38,9 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
         {
             "events": [{
                 "event": { .. serialized event .. },
+                "room_version": .., // "1", "2", "3", etc: the version of the room
+                                    // containing the event
+                "event_format_version": .., // 1,2,3 etc: the event format version
                 "internal_metadata": { .. serialized internal_metadata .. },
                 "rejected_reason": ..,   // The event.rejected_reason field
                 "context": { .. serialized event context .. },
@@ -73,6 +76,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
             event_payloads.append(
                 {
                     "event": event.get_pdu_json(),
+                    "room_version": event.room_version.identifier,
                     "event_format_version": event.format_version,
                     "internal_metadata": event.internal_metadata.get_dict(),
                     "rejected_reason": event.rejected_reason,
@@ -95,12 +99,13 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
             event_and_contexts = []
             for event_payload in event_payloads:
                 event_dict = event_payload["event"]
-                format_ver = event_payload["event_format_version"]
+                room_ver = KNOWN_ROOM_VERSIONS[event_payload["room_version"]]
                 internal_metadata = event_payload["internal_metadata"]
                 rejected_reason = event_payload["rejected_reason"]
 
-                EventType = event_type_from_format_version(format_ver)
-                event = EventType(event_dict, internal_metadata, rejected_reason)
+                event = make_event_from_dict(
+                    event_dict, room_ver, internal_metadata, rejected_reason
+                )
 
                 context = EventContext.deserialize(
                     self.storage, event_payload["context"]
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index 84b92f16ad..b74b088ff4 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -17,7 +17,8 @@ import logging
 
 from twisted.internet import defer
 
-from synapse.events import event_type_from_format_version
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
+from synapse.events import make_event_from_dict
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
@@ -37,6 +38,9 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
 
         {
             "event": { .. serialized event .. },
+            "room_version": .., // "1", "2", "3", etc: the version of the room
+                                // containing the event
+            "event_format_version": .., // 1,2,3 etc: the event format version
             "internal_metadata": { .. serialized internal_metadata .. },
             "rejected_reason": ..,   // The event.rejected_reason field
             "context": { .. serialized event context .. },
@@ -77,6 +81,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
 
         payload = {
             "event": event.get_pdu_json(),
+            "room_version": event.room_version.identifier,
             "event_format_version": event.format_version,
             "internal_metadata": event.internal_metadata.get_dict(),
             "rejected_reason": event.rejected_reason,
@@ -93,12 +98,13 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             content = parse_json_object_from_request(request)
 
             event_dict = content["event"]
-            format_ver = content["event_format_version"]
+            room_ver = KNOWN_ROOM_VERSIONS[content["room_version"]]
             internal_metadata = content["internal_metadata"]
             rejected_reason = content["rejected_reason"]
 
-            EventType = event_type_from_format_version(format_ver)
-            event = EventType(event_dict, internal_metadata, rejected_reason)
+            event = make_event_from_dict(
+                event_dict, room_ver, internal_metadata, rejected_reason
+            )
 
             requester = Requester.deserialize(self.store, content["requester"])
             context = EventContext.deserialize(self.storage, content["context"])