Implement the push rules for experimental MSC4306: Thread Subscriptions.

changelog.d/18762.feature

@@ -0,0 +1 @@
+Implement the push rules for experimental [MSC4306: Thread Subscriptions](https://github.com/matrix-org/matrix-doc/issues/4306).

rust/benches/evaluator.rs

@@ -61,6 +61,7 @@ fn bench_match_exact(b: &mut Bencher) {
         vec![],
         false,
         false,
+        false,
     )
     .unwrap();
 
@@ -71,10 +72,10 @@ fn bench_match_exact(b: &mut Bencher) {
         },
     ));
 
-    let matched = eval.match_condition(&condition, None, None).unwrap();
+    let matched = eval.match_condition(&condition, None, None, None).unwrap();
     assert!(matched, "Didn't match");
 
-    b.iter(|| eval.match_condition(&condition, None, None).unwrap());
+    b.iter(|| eval.match_condition(&condition, None, None, None).unwrap());
 }
 
 #[bench]
@@ -107,6 +108,7 @@ fn bench_match_word(b: &mut Bencher) {
         vec![],
         false,
         false,
+        false,
     )
     .unwrap();
 
@@ -117,10 +119,10 @@ fn bench_match_word(b: &mut Bencher) {
         },
     ));
 
-    let matched = eval.match_condition(&condition, None, None).unwrap();
+    let matched = eval.match_condition(&condition, None, None, None).unwrap();
     assert!(matched, "Didn't match");
 
-    b.iter(|| eval.match_condition(&condition, None, None).unwrap());
+    b.iter(|| eval.match_condition(&condition, None, None, None).unwrap());
 }
 
 #[bench]
@@ -153,6 +155,7 @@ fn bench_match_word_miss(b: &mut Bencher) {
         vec![],
         false,
         false,
+        false,
     )
     .unwrap();
 
@@ -163,10 +166,10 @@ fn bench_match_word_miss(b: &mut Bencher) {
         },
     ));
 
-    let matched = eval.match_condition(&condition, None, None).unwrap();
+    let matched = eval.match_condition(&condition, None, None, None).unwrap();
     assert!(!matched, "Didn't match");
 
-    b.iter(|| eval.match_condition(&condition, None, None).unwrap());
+    b.iter(|| eval.match_condition(&condition, None, None, None).unwrap());
 }
 
 #[bench]
@@ -199,6 +202,7 @@ fn bench_eval_message(b: &mut Bencher) {
         vec![],
         false,
         false,
+        false,
     )
     .unwrap();
 
@@ -210,7 +214,8 @@ fn bench_eval_message(b: &mut Bencher) {
         false,
         false,
         false,
+        false,
     );
 
-    b.iter(|| eval.run(&rules, Some("bob"), Some("person")));
+    b.iter(|| eval.run(&rules, Some("bob"), Some("person"), None));
 }

rust/src/push/base_rules.rs

@@ -290,6 +290,26 @@ pub const BASE_APPEND_CONTENT_RULES: &[PushRule] = &[PushRule {
 }];
 
 pub const BASE_APPEND_UNDERRIDE_RULES: &[PushRule] = &[
+    PushRule {
+        rule_id: Cow::Borrowed("global/content/.io.element.msc4306.rule.unsubscribed_thread"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(
+            KnownCondition::Msc4306ThreadSubscription { subscribed: false },
+        )]),
+        actions: Cow::Borrowed(&[]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/content/.io.element.msc4306.rule.subscribed_thread"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(
+            KnownCondition::Msc4306ThreadSubscription { subscribed: true },
+        )]),
+        actions: Cow::Borrowed(&[Action::Notify, SOUND_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
     PushRule {
         rule_id: Cow::Borrowed("global/underride/.m.rule.call"),
         priority_class: 1,

rust/src/push/evaluator.rs

@@ -106,8 +106,11 @@ pub struct PushRuleEvaluator {
     /// flag as MSC1767 (extensible events core).
     msc3931_enabled: bool,
 
-    // If MSC4210 (remove legacy mentions) is enabled.
+    /// If MSC4210 (remove legacy mentions) is enabled.
     msc4210_enabled: bool,
+
+    /// If MSC4306 (thread subscriptions) is enabled.
+    msc4306_enabled: bool,
 }
 
 #[pymethods]
@@ -126,6 +129,7 @@ impl PushRuleEvaluator {
         room_version_feature_flags,
         msc3931_enabled,
         msc4210_enabled,
+        msc4306_enabled,
     ))]
     pub fn py_new(
         flattened_keys: BTreeMap<String, JsonValue>,
@@ -138,6 +142,7 @@ impl PushRuleEvaluator {
         room_version_feature_flags: Vec<String>,
         msc3931_enabled: bool,
         msc4210_enabled: bool,
+        msc4306_enabled: bool,
     ) -> Result<Self, Error> {
         let body = match flattened_keys.get("content.body") {
             Some(JsonValue::Value(SimpleJsonValue::Str(s))) => s.clone().into_owned(),
@@ -156,6 +161,7 @@ impl PushRuleEvaluator {
             room_version_feature_flags,
             msc3931_enabled,
             msc4210_enabled,
+            msc4306_enabled,
         })
     }
 
@@ -167,12 +173,19 @@ impl PushRuleEvaluator {
     ///
     /// Returns the set of actions, if any, that match (filtering out any
     /// `dont_notify` and `coalesce` actions).
-    #[pyo3(signature = (push_rules, user_id=None, display_name=None))]
+    ///
+    /// msc4306_thread_subscription_state: (Only populated if MSC4306 is enabled)
+    /// The thread subscription state corresponding to the thread containing this event.
+    /// - `None` if the event is not in a thread, or if MSC4306 is disabled.
+    /// - `Some(true)` if the event is in a thread and the user has a subscription for that thread
+    /// - `Some(false)` if the event is in a thread and the user does NOT have a subscription for that thread
+    #[pyo3(signature = (push_rules, user_id=None, display_name=None, msc4306_thread_subscription_state=None))]
     pub fn run(
         &self,
         push_rules: &FilteredPushRules,
         user_id: Option<&str>,
         display_name: Option<&str>,
+        msc4306_thread_subscription_state: Option<bool>,
     ) -> Vec<Action> {
         'outer: for (push_rule, enabled) in push_rules.iter() {
             if !enabled {
@@ -204,7 +217,12 @@ impl PushRuleEvaluator {
                     Condition::Known(KnownCondition::RoomVersionSupports { feature: _ }),
                 );
 
-                match self.match_condition(condition, user_id, display_name) {
+                match self.match_condition(
+                    condition,
+                    user_id,
+                    display_name,
+                    msc4306_thread_subscription_state,
+                ) {
                     Ok(true) => {}
                     Ok(false) => continue 'outer,
                     Err(err) => {
@@ -237,14 +255,20 @@ impl PushRuleEvaluator {
     }
 
     /// Check if the given condition matches.
-    #[pyo3(signature = (condition, user_id=None, display_name=None))]
+    #[pyo3(signature = (condition, user_id=None, display_name=None, msc4306_thread_subscription_state=None))]
     fn matches(
         &self,
         condition: Condition,
         user_id: Option<&str>,
         display_name: Option<&str>,
+        msc4306_thread_subscription_state: Option<bool>,
     ) -> bool {
-        match self.match_condition(&condition, user_id, display_name) {
+        match self.match_condition(
+            &condition,
+            user_id,
+            display_name,
+            msc4306_thread_subscription_state,
+        ) {
             Ok(true) => true,
             Ok(false) => false,
             Err(err) => {
@@ -262,6 +286,7 @@ impl PushRuleEvaluator {
         condition: &Condition,
         user_id: Option<&str>,
         display_name: Option<&str>,
+        msc4306_thread_subscription_state: Option<bool>,
     ) -> Result<bool, Error> {
         let known_condition = match condition {
             Condition::Known(known) => known,
@@ -393,6 +418,13 @@ impl PushRuleEvaluator {
                         && self.room_version_feature_flags.contains(&flag)
                 }
             }
+            KnownCondition::Msc4306ThreadSubscription { subscribed } => {
+                if !self.msc4306_enabled {
+                    false
+                } else {
+                    msc4306_thread_subscription_state == Some(*subscribed)
+                }
+            }
         };
 
         Ok(result)
@@ -536,10 +568,11 @@ fn push_rule_evaluator() {
         vec![],
         true,
         false,
+        false,
     )
     .unwrap();
 
-    let result = evaluator.run(&FilteredPushRules::default(), None, Some("bob"));
+    let result = evaluator.run(&FilteredPushRules::default(), None, Some("bob"), None);
     assert_eq!(result.len(), 3);
 }
 
@@ -566,6 +599,7 @@ fn test_requires_room_version_supports_condition() {
         flags,
         true,
         false,
+        false,
     )
     .unwrap();
 
@@ -575,6 +609,7 @@ fn test_requires_room_version_supports_condition() {
         &FilteredPushRules::default(),
         Some("@bob:example.org"),
         None,
+        None,
     );
     assert_eq!(result.len(), 3);
 
@@ -593,7 +628,17 @@ fn test_requires_room_version_supports_condition() {
     };
     let rules = PushRules::new(vec![custom_rule]);
     result = evaluator.run(
-        &FilteredPushRules::py_new(rules, BTreeMap::new(), true, false, true, false, false),
+        &FilteredPushRules::py_new(
+            rules,
+            BTreeMap::new(),
+            true,
+            false,
+            true,
+            false,
+            false,
+            false,
+        ),
+        None,
         None,
         None,
     );

rust/src/push/mod.rs

@@ -369,6 +369,10 @@ pub enum KnownCondition {
     RoomVersionSupports {
         feature: Cow<'static, str>,
     },
+    #[serde(rename = "io.element.msc4306.thread_subscription")]
+    Msc4306ThreadSubscription {
+        subscribed: bool,
+    },
 }
 
 impl<'source> IntoPyObject<'source> for Condition {
@@ -547,11 +551,13 @@ pub struct FilteredPushRules {
     msc3664_enabled: bool,
     msc4028_push_encrypted_events: bool,
     msc4210_enabled: bool,
+    msc4306_enabled: bool,
 }
 
 #[pymethods]
 impl FilteredPushRules {
     #[new]
+    #[allow(clippy::too_many_arguments)]
     pub fn py_new(
         push_rules: PushRules,
         enabled_map: BTreeMap<String, bool>,
@@ -560,6 +566,7 @@ impl FilteredPushRules {
         msc3664_enabled: bool,
         msc4028_push_encrypted_events: bool,
         msc4210_enabled: bool,
+        msc4306_enabled: bool,
     ) -> Self {
         Self {
             push_rules,
@@ -569,6 +576,7 @@ impl FilteredPushRules {
             msc3664_enabled,
             msc4028_push_encrypted_events,
             msc4210_enabled,
+            msc4306_enabled,
         }
     }
 
@@ -619,6 +627,10 @@ impl FilteredPushRules {
                     return false;
                 }
 
+                if !self.msc4306_enabled && rule.rule_id.contains("/.io.element.msc4306.rule.") {
+                    return false;
+                }
+
                 true
             })
             .map(|r| {

synapse/push/bulk_push_rule_evaluator.py

@@ -25,6 +25,7 @@
     Any,
     Collection,
     Dict,
+    FrozenSet,
     List,
     Mapping,
     Optional,
@@ -477,8 +478,18 @@ async def _action_for_event_by_user(
             event.room_version.msc3931_push_features,
             self.hs.config.experimental.msc1767_enabled,  # MSC3931 flag
             self.hs.config.experimental.msc4210_enabled,
+            self.hs.config.experimental.msc4306_enabled,
         )
 
+        msc4306_thread_subscribers: Optional[FrozenSet[str]] = None
+        if self.hs.config.experimental.msc4306_enabled and thread_id != MAIN_TIMELINE:
+            # pull out, in batch, all local subscribers to this thread
+            # (in the common case, they will all be getting processed for push
+            # rules right now)
+            msc4306_thread_subscribers = await self.store.get_subscribers_to_thread(
+                event.room_id, thread_id
+            )
+
         for uid, rules in rules_by_user.items():
             if event.sender == uid:
                 continue
@@ -503,7 +514,13 @@ async def _action_for_event_by_user(
                 # current user, it'll be added to the dict later.
                 actions_by_user[uid] = []
 
-            actions = evaluator.run(rules, uid, display_name)
+            msc4306_thread_subscription_state: Optional[bool] = None
+            if msc4306_thread_subscribers is not None:
+                msc4306_thread_subscription_state = uid in msc4306_thread_subscribers
+
+            actions = evaluator.run(
+                rules, uid, display_name, msc4306_thread_subscription_state
+            )
             if "notify" in actions:
                 # Push rules say we should notify the user of this event
                 actions_by_user[uid] = actions

synapse/storage/databases/main/push_rule.py

@@ -110,6 +110,7 @@ def _load_rules(
         msc3381_polls_enabled=experimental_config.msc3381_polls_enabled,
         msc4028_push_encrypted_events=experimental_config.msc4028_push_encrypted_events,
         msc4210_enabled=experimental_config.msc4210_enabled,
+        msc4306_enabled=experimental_config.msc4306_enabled,
     )
 
     return filtered_rules