Fix sending events into rooms with non-integer power levels (#14073)

Author: David Robertson

changelog.d/14073.misc

@@ -0,0 +1 @@
+Fix a bug introduced in Synapse 1.68.0 where messages could not be sent in rooms with non-integer `notifications` power level.

mypy.ini

@@ -106,6 +106,9 @@ disallow_untyped_defs = False
 [mypy-tests.handlers.test_user_directory]
 disallow_untyped_defs = True
 
+[mypy-tests.push.test_bulk_push_rule_evaluator]
+disallow_untyped_defs = True
+
 [mypy-tests.test_server]
 disallow_untyped_defs = True
 

synapse/push/bulk_push_rule_evaluator.py

@@ -289,11 +289,18 @@ async def action_for_event_by_user(
             if relation.rel_type == RelationTypes.THREAD:
                 thread_id = relation.parent_id
 
+        # It's possible that old room versions have non-integer power levels (floats or
+        # strings). Workaround this by explicitly converting to int.
+        notification_levels = power_levels.get("notifications", {})
+        if not event.room_version.msc3667_int_only_power_levels:
+            for user_id, level in notification_levels.items():
+                notification_levels[user_id] = int(level)
+
         evaluator = PushRuleEvaluator(
             _flatten_dict(event),
             room_member_count,
             sender_power_level,
-            power_levels.get("notifications", {}),
+            notification_levels,
             relations,
             self._relations_match_enabled,
         )

tests/push/test_bulk_push_rule_evaluator.py

@@ -0,0 +1,74 @@
+from unittest.mock import patch
+
+from synapse.api.room_versions import RoomVersions
+from synapse.push.bulk_push_rule_evaluator import BulkPushRuleEvaluator
+from synapse.rest import admin
+from synapse.rest.client import login, register, room
+from synapse.types import create_requester
+
+from tests import unittest
+
+
+class TestBulkPushRuleEvaluator(unittest.HomeserverTestCase):
+
+    servlets = [
+        admin.register_servlets_for_client_rest_resource,
+        room.register_servlets,
+        login.register_servlets,
+        register.register_servlets,
+    ]
+
+    def test_action_for_event_by_user_handles_noninteger_power_levels(self) -> None:
+        """We should convert floats and strings to integers before passing to Rust.
+
+        Reproduces #14060.
+
+        A lack of validation: the gift that keeps on giving.
+        """
+        # Create a new user and room.
+        alice = self.register_user("alice", "pass")
+        token = self.login(alice, "pass")
+
+        room_id = self.helper.create_room_as(
+            alice, room_version=RoomVersions.V9.identifier, tok=token
+        )
+
+        # Alter the power levels in that room to include stringy and floaty levels.
+        # We need to suppress the validation logic or else it will reject these dodgy
+        # values. (Presumably this validation was not always present.)
+        event_creation_handler = self.hs.get_event_creation_handler()
+        requester = create_requester(alice)
+        with patch("synapse.events.validator.validate_canonicaljson"), patch(
+            "synapse.events.validator.jsonschema.validate"
+        ):
+            self.helper.send_state(
+                room_id,
+                "m.room.power_levels",
+                {
+                    "users": {alice: "100"},  # stringy
+                    "notifications": {"room": 100.0},  # float
+                },
+                token,
+                state_key="",
+            )
+
+        # Create a new message event, and try to evaluate it under the dodgy
+        # power level event.
+        event, context = self.get_success(
+            event_creation_handler.create_event(
+                requester,
+                {
+                    "type": "m.room.message",
+                    "room_id": room_id,
+                    "content": {
+                        "msgtype": "m.text",
+                        "body": "helo",
+                    },
+                    "sender": alice,
+                },
+            )
+        )
+
+        bulk_evaluator = BulkPushRuleEvaluator(self.hs)
+        # should not raise
+        self.get_success(bulk_evaluator.action_for_event_by_user(event, context))