Support the backwards compatibility features in MSC3952. (#14958)

If the feature is enabled and the event has a `m.mentions` property,
skip processing of the legacy mentions rules.

7 files changed, 184 insertions, 59 deletions

diff --git a/changelog.d/14958.feature b/changelog.d/14958.feature
new file mode 100644
index 0000000000..8293e99eff
--- /dev/null
+++ b/changelog.d/14958.feature
@@ -0,0 +1 @@
+Experimental support for [MSC3952](https://github.com/matrix-org/matrix-spec-proposals/pull/3952): intentional mentions.
diff --git a/rust/benches/evaluator.rs b/rust/benches/evaluator.rs
index 6b16a3f75b..859d54961c 100644
--- a/rust/benches/evaluator.rs
+++ b/rust/benches/evaluator.rs
@@ -33,6 +33,7 @@ fn bench_match_exact(b: &mut Bencher) {
 
     let eval = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
@@ -71,6 +72,7 @@ fn bench_match_word(b: &mut Bencher) {
 
     let eval = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
@@ -109,6 +111,7 @@ fn bench_match_word_miss(b: &mut Bencher) {
 
     let eval = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
@@ -147,6 +150,7 @@ fn bench_eval_message(b: &mut Bencher) {
 
     let eval = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
diff --git a/rust/src/push/evaluator.rs b/rust/src/push/evaluator.rs
index aa71202e43..da6f704c0e 100644
--- a/rust/src/push/evaluator.rs
+++ b/rust/src/push/evaluator.rs
@@ -68,6 +68,8 @@ pub struct PushRuleEvaluator {
     /// The "content.body", if any.
     body: String,
 
+    /// True if the event has a mentions property and MSC3952 support is enabled.
+    has_mentions: bool,
     /// The user mentions that were part of the message.
     user_mentions: BTreeSet<String>,
     /// True if the message is a room message.
@@ -105,6 +107,7 @@ impl PushRuleEvaluator {
     #[new]
     pub fn py_new(
         flattened_keys: BTreeMap<String, String>,
+        has_mentions: bool,
         user_mentions: BTreeSet<String>,
         room_mention: bool,
         room_member_count: u64,
@@ -123,6 +126,7 @@ impl PushRuleEvaluator {
         Ok(PushRuleEvaluator {
             flattened_keys,
             body,
+            has_mentions,
             user_mentions,
             room_mention,
             room_member_count,
@@ -155,6 +159,19 @@ impl PushRuleEvaluator {
             }
 
             let rule_id = &push_rule.rule_id().to_string();
+
+            // For backwards-compatibility the legacy mention rules are disabled
+            // if the event contains the 'm.mentions' property (and if the
+            // experimental feature is enabled, both of these are represented
+            // by the has_mentions flag).
+            if self.has_mentions
+                && (rule_id == "global/override/.m.rule.contains_display_name"
+                    || rule_id == "global/content/.m.rule.contains_user_name"
+                    || rule_id == "global/override/.m.rule.roomnotif")
+            {
+                continue;
+            }
+
             let extev_flag = &RoomVersionFeatures::ExtensibleEvents.as_str().to_string();
             let supports_extensible_events = self.room_version_feature_flags.contains(extev_flag);
             let safe_from_rver_condition = SAFE_EXTENSIBLE_EVENTS_RULE_IDS.contains(rule_id);
@@ -441,6 +458,7 @@ fn push_rule_evaluator() {
     flattened_keys.insert("content.body".to_string(), "foo bar bob hello".to_string());
     let evaluator = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
@@ -468,6 +486,7 @@ fn test_requires_room_version_supports_condition() {
     let flags = vec![RoomVersionFeatures::ExtensibleEvents.as_str().to_string()];
     let evaluator = PushRuleEvaluator::py_new(
         flattened_keys,
+        false,
         BTreeSet::new(),
         false,
         10,
diff --git a/stubs/synapse/synapse_rust/push.pyi b/stubs/synapse/synapse_rust/push.pyi
index 588d90c25a..c0af2af3df 100644
--- a/stubs/synapse/synapse_rust/push.pyi
+++ b/stubs/synapse/synapse_rust/push.pyi
@@ -56,6 +56,7 @@ class PushRuleEvaluator:
     def __init__(
         self,
         flattened_keys: Mapping[str, str],
+        has_mentions: bool,
         user_mentions: Set[str],
         room_mention: bool,
         room_member_count: int,
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 88cfc05d05..9bf92b9765 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -119,6 +119,9 @@ class BulkPushRuleEvaluator:
         self.should_calculate_push_rules = self.hs.config.push.enable_push
 
         self._related_event_match_enabled = self.hs.config.experimental.msc3664_enabled
+        self._intentional_mentions_enabled = (
+            self.hs.config.experimental.msc3952_intentional_mentions
+        )
 
         self.room_push_rule_cache_metrics = register_cache(
             "cache",
@@ -364,9 +367,12 @@ class BulkPushRuleEvaluator:
 
         # Pull out any user and room mentions.
         mentions = event.content.get(EventContentFields.MSC3952_MENTIONS)
+        has_mentions = self._intentional_mentions_enabled and isinstance(mentions, dict)
         user_mentions: Set[str] = set()
         room_mention = False
-        if isinstance(mentions, dict):
+        if has_mentions:
+            # mypy seems to have lost the type even though it must be a dict here.
+            assert isinstance(mentions, dict)
             # Remove out any non-string items and convert to a set.
             user_mentions_raw = mentions.get("user_ids")
             if isinstance(user_mentions_raw, list):
@@ -378,6 +384,7 @@ class BulkPushRuleEvaluator:
 
         evaluator = PushRuleEvaluator(
             _flatten_dict(event, room_version=event.room_version),
+            has_mentions,
             user_mentions,
             room_mention,
             room_member_count,
diff --git a/tests/push/test_bulk_push_rule_evaluator.py b/tests/push/test_bulk_push_rule_evaluator.py
index fda48d9f61..3b2d082dcb 100644
--- a/tests/push/test_bulk_push_rule_evaluator.py
+++ b/tests/push/test_bulk_push_rule_evaluator.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import Any
+from typing import Any, Optional
 from unittest.mock import patch
 
 from parameterized import parameterized
@@ -25,7 +25,7 @@ from synapse.push.bulk_push_rule_evaluator import BulkPushRuleEvaluator
 from synapse.rest import admin
 from synapse.rest.client import login, register, room
 from synapse.server import HomeServer
-from synapse.types import create_requester
+from synapse.types import JsonDict, create_requester
 from synapse.util import Clock
 
 from tests.test_utils import simple_async_mock
@@ -196,77 +196,144 @@ class TestBulkPushRuleEvaluator(HomeserverTestCase):
         self.get_success(bulk_evaluator.action_for_events_by_user([(event, context)]))
         bulk_evaluator._action_for_event_by_user.assert_not_called()
 
-    @override_config({"experimental_features": {"msc3952_intentional_mentions": True}})
-    def test_mentions(self) -> None:
-        """Test the behavior of an event which includes invalid mentions."""
-        bulk_evaluator = BulkPushRuleEvaluator(self.hs)
-
-        sentinel = object()
-
-        def create_and_process(mentions: Any = sentinel) -> bool:
-            """Returns true iff the `mentions` trigger an event push action."""
-            content = {}
-            if mentions is not sentinel:
-                content[EventContentFields.MSC3952_MENTIONS] = mentions
-
-            # Create a new message event which should cause a notification.
-            event, context = self.get_success(
-                self.event_creation_handler.create_event(
-                    self.requester,
-                    {
-                        "type": "test",
-                        "room_id": self.room_id,
-                        "content": content,
-                        "sender": f"@bob:{self.hs.hostname}",
-                    },
-                )
+    def _create_and_process(
+        self, bulk_evaluator: BulkPushRuleEvaluator, content: Optional[JsonDict] = None
+    ) -> bool:
+        """Returns true iff the `mentions` trigger an event push action."""
+        # Create a new message event which should cause a notification.
+        event, context = self.get_success(
+            self.event_creation_handler.create_event(
+                self.requester,
+                {
+                    "type": "test",
+                    "room_id": self.room_id,
+                    "content": content or {},
+                    "sender": f"@bob:{self.hs.hostname}",
+                },
             )
+        )
 
-            # Ensure no actions are generated!
-            self.get_success(
-                bulk_evaluator.action_for_events_by_user([(event, context)])
-            )
+        # Execute the push rule machinery.
+        self.get_success(bulk_evaluator.action_for_events_by_user([(event, context)]))
 
-            # If any actions are generated for this event, return true.
-            result = self.get_success(
-                self.hs.get_datastores().main.db_pool.simple_select_list(
-                    table="event_push_actions_staging",
-                    keyvalues={"event_id": event.event_id},
-                    retcols=("*",),
-                    desc="get_event_push_actions_staging",
-                )
+        # If any actions are generated for this event, return true.
+        result = self.get_success(
+            self.hs.get_datastores().main.db_pool.simple_select_list(
+                table="event_push_actions_staging",
+                keyvalues={"event_id": event.event_id},
+                retcols=("*",),
+                desc="get_event_push_actions_staging",
             )
-            return len(result) > 0
+        )
+        return len(result) > 0
+
+    @override_config({"experimental_features": {"msc3952_intentional_mentions": True}})
+    def test_user_mentions(self) -> None:
+        """Test the behavior of an event which includes invalid user mentions."""
+        bulk_evaluator = BulkPushRuleEvaluator(self.hs)
 
         # Not including the mentions field should not notify.
-        self.assertFalse(create_and_process())
+        self.assertFalse(self._create_and_process(bulk_evaluator))
         # An empty mentions field should not notify.
-        self.assertFalse(create_and_process({}))
+        self.assertFalse(
+            self._create_and_process(
+                bulk_evaluator, {EventContentFields.MSC3952_MENTIONS: {}}
+            )
+        )
 
         # Non-dict mentions should be ignored.
         mentions: Any
         for mentions in (None, True, False, 1, "foo", []):
-            self.assertFalse(create_and_process(mentions))
+            self.assertFalse(
+                self._create_and_process(
+                    bulk_evaluator, {EventContentFields.MSC3952_MENTIONS: mentions}
+                )
+            )
 
         # A non-list should be ignored.
         for mentions in (None, True, False, 1, "foo", {}):
-            self.assertFalse(create_and_process({"user_ids": mentions}))
+            self.assertFalse(
+                self._create_and_process(
+                    bulk_evaluator,
+                    {EventContentFields.MSC3952_MENTIONS: {"user_ids": mentions}},
+                )
+            )
 
         # The Matrix ID appearing anywhere in the list should notify.
-        self.assertTrue(create_and_process({"user_ids": [self.alice]}))
-        self.assertTrue(create_and_process({"user_ids": ["@another:test", self.alice]}))
+        self.assertTrue(
+            self._create_and_process(
+                bulk_evaluator,
+                {EventContentFields.MSC3952_MENTIONS: {"user_ids": [self.alice]}},
+            )
+        )
+        self.assertTrue(
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    EventContentFields.MSC3952_MENTIONS: {
+                        "user_ids": ["@another:test", self.alice]
+                    }
+                },
+            )
+        )
 
         # Duplicate user IDs should notify.
-        self.assertTrue(create_and_process({"user_ids": [self.alice, self.alice]}))
+        self.assertTrue(
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    EventContentFields.MSC3952_MENTIONS: {
+                        "user_ids": [self.alice, self.alice]
+                    }
+                },
+            )
+        )
 
         # Invalid entries in the list are ignored.
-        self.assertFalse(create_and_process({"user_ids": [None, True, False, {}, []]}))
+        self.assertFalse(
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    EventContentFields.MSC3952_MENTIONS: {
+                        "user_ids": [None, True, False, {}, []]
+                    }
+                },
+            )
+        )
         self.assertTrue(
-            create_and_process({"user_ids": [None, True, False, {}, [], self.alice]})
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    EventContentFields.MSC3952_MENTIONS: {
+                        "user_ids": [None, True, False, {}, [], self.alice]
+                    }
+                },
+            )
         )
 
+        # The legacy push rule should not mention if the mentions field exists.
+        self.assertFalse(
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    "body": self.alice,
+                    "msgtype": "m.text",
+                    EventContentFields.MSC3952_MENTIONS: {},
+                },
+            )
+        )
+
+    @override_config({"experimental_features": {"msc3952_intentional_mentions": True}})
+    def test_room_mentions(self) -> None:
+        """Test the behavior of an event which includes invalid room mentions."""
+        bulk_evaluator = BulkPushRuleEvaluator(self.hs)
+
         # Room mentions from those without power should not notify.
-        self.assertFalse(create_and_process({"room": True}))
+        self.assertFalse(
+            self._create_and_process(
+                bulk_evaluator, {EventContentFields.MSC3952_MENTIONS: {"room": True}}
+            )
+        )
 
         # Room mentions from those with power should notify.
         self.helper.send_state(
@@ -276,8 +343,30 @@ class TestBulkPushRuleEvaluator(HomeserverTestCase):
             self.token,
             state_key="",
         )
-        self.assertTrue(create_and_process({"room": True}))
+        self.assertTrue(
+            self._create_and_process(
+                bulk_evaluator, {EventContentFields.MSC3952_MENTIONS: {"room": True}}
+            )
+        )
 
         # Invalid data should not notify.
+        mentions: Any
         for mentions in (None, False, 1, "foo", [], {}):
-            self.assertFalse(create_and_process({"room": mentions}))
+            self.assertFalse(
+                self._create_and_process(
+                    bulk_evaluator,
+                    {EventContentFields.MSC3952_MENTIONS: {"room": mentions}},
+                )
+            )
+
+        # The legacy push rule should not mention if the mentions field exists.
+        self.assertFalse(
+            self._create_and_process(
+                bulk_evaluator,
+                {
+                    "body": "@room",
+                    "msgtype": "m.text",
+                    EventContentFields.MSC3952_MENTIONS: {},
+                },
+            )
+        )
diff --git a/tests/push/test_push_rule_evaluator.py b/tests/push/test_push_rule_evaluator.py
index 9d01c989d4..81661e181b 100644
--- a/tests/push/test_push_rule_evaluator.py
+++ b/tests/push/test_push_rule_evaluator.py
@@ -42,6 +42,7 @@ class PushRuleEvaluatorTestCase(unittest.TestCase):
         self,
         content: JsonMapping,
         *,
+        has_mentions: bool = False,
         user_mentions: Optional[Set[str]] = None,
         room_mention: bool = False,
         related_events: Optional[JsonDict] = None,
@@ -62,6 +63,7 @@ class PushRuleEvaluatorTestCase(unittest.TestCase):
         power_levels: Dict[str, Union[int, Dict[str, int]]] = {}
         return PushRuleEvaluator(
             _flatten_dict(event),
+            has_mentions,
             user_mentions or set(),
             room_mention,
             room_member_count,
@@ -102,19 +104,21 @@ class PushRuleEvaluatorTestCase(unittest.TestCase):
         condition = {"kind": "org.matrix.msc3952.is_user_mention"}
 
         # No mentions shouldn't match.
-        evaluator = self._get_evaluator({})
+        evaluator = self._get_evaluator({}, has_mentions=True)
         self.assertFalse(evaluator.matches(condition, "@user:test", None))
 
         # An empty set shouldn't match
-        evaluator = self._get_evaluator({}, user_mentions=set())
+        evaluator = self._get_evaluator({}, has_mentions=True, user_mentions=set())
         self.assertFalse(evaluator.matches(condition, "@user:test", None))
 
         # The Matrix ID appearing anywhere in the mentions list should match
-        evaluator = self._get_evaluator({}, user_mentions={"@user:test"})
+        evaluator = self._get_evaluator(
+            {}, has_mentions=True, user_mentions={"@user:test"}
+        )
         self.assertTrue(evaluator.matches(condition, "@user:test", None))
 
         evaluator = self._get_evaluator(
-            {}, user_mentions={"@another:test", "@user:test"}
+            {}, has_mentions=True, user_mentions={"@another:test", "@user:test"}
         )
         self.assertTrue(evaluator.matches(condition, "@user:test", None))
 
@@ -126,16 +130,16 @@ class PushRuleEvaluatorTestCase(unittest.TestCase):
         condition = {"kind": "org.matrix.msc3952.is_room_mention"}
 
         # No room mention shouldn't match.
-        evaluator = self._get_evaluator({})
+        evaluator = self._get_evaluator({}, has_mentions=True)
         self.assertFalse(evaluator.matches(condition, None, None))
 
         # Room mention should match.
-        evaluator = self._get_evaluator({}, room_mention=True)
+        evaluator = self._get_evaluator({}, has_mentions=True, room_mention=True)
         self.assertTrue(evaluator.matches(condition, None, None))
 
         # A room mention and user mention is valid.
         evaluator = self._get_evaluator(
-            {}, user_mentions={"@another:test"}, room_mention=True
+            {}, has_mentions=True, user_mentions={"@another:test"}, room_mention=True
         )
         self.assertTrue(evaluator.matches(condition, None, None))