Implement MSC3958: suppress notifications from edits (#14960)

Co-authored-by: Brad Murray <brad@beeper.com>
Co-authored-by: Nick Barrett <nick@beeper.com>

Copy the suppress_edits push rule from Beeper to implement MSC3958.

https://github.com/beeper/synapse/blame/9415a1284b1bfb558bd66f28c24ca1611e6c6fa2/rust/src/push/base_rules.rs#L98-L114

3 files changed, 26 insertions, 1 deletions

diff --git a/rust/src/push/base_rules.rs b/rust/src/push/base_rules.rs
index 49add4e951..e9af26dd4f 100644
--- a/rust/src/push/base_rules.rs
+++ b/rust/src/push/base_rules.rs
@@ -63,6 +63,23 @@ pub const BASE_PREPEND_OVERRIDE_RULES: &[PushRule] = &[PushRule {
 }];
 
 pub const BASE_APPEND_OVERRIDE_RULES: &[PushRule] = &[
+    // We don't want to notify on edits. Not only can this be confusing in real
+    // time (2 notifications, one message) but it's especially confusing
+    // if a bridge needs to edit a previously backfilled message.
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.com.beeper.suppress_edits"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("content.m.relates_to.rel_type"),
+                pattern: Some(Cow::Borrowed("m.replace")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::DontNotify]),
+        default: true,
+        default_enabled: true,
+    },
     PushRule {
         rule_id: Cow::Borrowed("global/override/.m.rule.suppress_notices"),
         priority_class: 5,
diff --git a/rust/src/push/evaluator.rs b/rust/src/push/evaluator.rs
index da6f704c0e..ec7a8c4453 100644
--- a/rust/src/push/evaluator.rs
+++ b/rust/src/push/evaluator.rs
@@ -523,7 +523,7 @@ 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),
+        &FilteredPushRules::py_new(rules, BTreeMap::new(), true, false, true, false, false),
         None,
         None,
     );
diff --git a/rust/src/push/mod.rs b/rust/src/push/mod.rs
index 7e449f2433..3c4f876cab 100644
--- a/rust/src/push/mod.rs
+++ b/rust/src/push/mod.rs
@@ -419,6 +419,7 @@ pub struct FilteredPushRules {
     msc3381_polls_enabled: bool,
     msc3664_enabled: bool,
     msc3952_intentional_mentions: bool,
+    msc3958_suppress_edits_enabled: bool,
 }
 
 #[pymethods]
@@ -431,6 +432,7 @@ impl FilteredPushRules {
         msc3381_polls_enabled: bool,
         msc3664_enabled: bool,
         msc3952_intentional_mentions: bool,
+        msc3958_suppress_edits_enabled: bool,
     ) -> Self {
         Self {
             push_rules,
@@ -439,6 +441,7 @@ impl FilteredPushRules {
             msc3381_polls_enabled,
             msc3664_enabled,
             msc3952_intentional_mentions,
+            msc3958_suppress_edits_enabled,
         }
     }
 
@@ -476,6 +479,11 @@ impl FilteredPushRules {
                 {
                     return false;
                 }
+                if !self.msc3958_suppress_edits_enabled
+                    && rule.rule_id == "global/override/.com.beeper.suppress_edits"
+                {
+                    return false;
+                }
 
                 true
             })