Initial support for MSC3931: Room version push rule feature flags (#14520)

* Add support for MSC3931: Room Version Supports push rule condition

* Create experimental flag for future work, and use it to gate MSC3931

* Changelog entry

3 files changed, 29 insertions, 1 deletions

diff --git a/synapse/api/room_versions.py b/synapse/api/room_versions.py
index e37acb0f1e..1bd1ef3e2b 100644
--- a/synapse/api/room_versions.py
+++ b/synapse/api/room_versions.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Callable, Dict, Optional
+from typing import Callable, Dict, List, Optional
 
 import attr
 
@@ -91,6 +91,12 @@ class RoomVersion:
     msc3787_knock_restricted_join_rule: bool
     # MSC3667: Enforce integer power levels
     msc3667_int_only_power_levels: bool
+    # MSC3931: Adds a push rule condition for "room version feature flags", making
+    # some push rules room version dependent. Note that adding a flag to this list
+    # is not enough to mark it "supported": the push rule evaluator also needs to
+    # support the flag. Unknown flags are ignored by the evaluator, making conditions
+    # fail if used.
+    msc3931_push_features: List[str]
 
 
 class RoomVersions:
@@ -111,6 +117,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V2 = RoomVersion(
         "2",
@@ -129,6 +136,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V3 = RoomVersion(
         "3",
@@ -147,6 +155,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V4 = RoomVersion(
         "4",
@@ -165,6 +174,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V5 = RoomVersion(
         "5",
@@ -183,6 +193,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V6 = RoomVersion(
         "6",
@@ -201,6 +212,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     MSC2176 = RoomVersion(
         "org.matrix.msc2176",
@@ -219,6 +231,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V7 = RoomVersion(
         "7",
@@ -237,6 +250,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V8 = RoomVersion(
         "8",
@@ -255,6 +269,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V9 = RoomVersion(
         "9",
@@ -273,6 +288,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     MSC3787 = RoomVersion(
         "org.matrix.msc3787",
@@ -291,6 +307,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=True,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
     V10 = RoomVersion(
         "10",
@@ -309,6 +326,7 @@ class RoomVersions:
         msc2716_redactions=False,
         msc3787_knock_restricted_join_rule=True,
         msc3667_int_only_power_levels=True,
+        msc3931_push_features=[],
     )
     MSC2716v4 = RoomVersion(
         "org.matrix.msc2716v4",
@@ -327,6 +345,7 @@ class RoomVersions:
         msc2716_redactions=True,
         msc3787_knock_restricted_join_rule=False,
         msc3667_int_only_power_levels=False,
+        msc3931_push_features=[],
     )
 
 
diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py
index a503abf364..b3f51fc57d 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -128,3 +128,6 @@ class ExperimentalConfig(Config):
 
         # MSC3912: Relation-based redactions.
         self.msc3912_enabled: bool = experimental.get("msc3912_enabled", False)
+
+        # MSC1767 and friends: Extensible Events
+        self.msc1767_enabled: bool = experimental.get("msc1767_enabled", False)
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 75b7e126ca..9cc3da6d91 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -338,6 +338,10 @@ class BulkPushRuleEvaluator:
             for user_id, level in notification_levels.items():
                 notification_levels[user_id] = int(level)
 
+        room_version_features = event.room_version.msc3931_push_features
+        if not room_version_features:
+            room_version_features = []
+
         evaluator = PushRuleEvaluator(
             _flatten_dict(event),
             room_member_count,
@@ -345,6 +349,8 @@ class BulkPushRuleEvaluator:
             notification_levels,
             related_events,
             self._related_event_match_enabled,
+            room_version_features,
+            self.hs.config.experimental.msc1767_enabled,  # MSC3931 flag
         )
 
         users = rules_by_user.keys()