fix(rules): Skip none on combined rule serialization

src/sentry/incidents/endpoints/serializers/alert_rule.py

@@ -377,7 +377,9 @@ def get_attrs(
 
         serialized_alert_rules = serialize(alert_rules, user=user)
         serialized_alert_rule_map_by_id = {
-            serialized_alert["id"]: serialized_alert for serialized_alert in serialized_alert_rules
+            serialized_alert["id"]: serialized_alert
+            for serialized_alert in serialized_alert_rules
+            if serialized_alert
         }
 
         serialized_issue_rules = serialize(
@@ -386,7 +388,9 @@ def get_attrs(
             serializer=RuleSerializer(expand=self.expand),
         )
         serialized_issue_rule_map_by_id = {
-            serialized_rule["id"]: serialized_rule for serialized_rule in serialized_issue_rules
+            serialized_rule["id"]: serialized_rule
+            for serialized_rule in serialized_issue_rules
+            if serialized_rule
         }
 
         uptime_detectors = [

tests/sentry/incidents/endpoints/serializers/test_alert_rule.py

@@ -291,6 +291,31 @@ def test_combined_serializer(self) -> None:
         serialized_uptime_monitor["type"] = "uptime"
         assert result[3] == serialized_uptime_monitor
 
+    @patch("sentry.api.serializers.models.rule.RuleSerializer.serialize")
+    @patch("sentry.api.serializers.base.logger")
+    def test_combined_serializer_failure(self, mock_logger, mock_serialize: MagicMock) -> None:
+        mock_serialize.side_effect = Exception
+
+        projects = [self.project, self.create_project()]
+        alert_rule = self.create_alert_rule(projects=projects)
+        issue_rule = self.create_issue_alert_rule(
+            data={
+                "project": self.project,
+                "name": "Issue Rule Test",
+                "conditions": [],
+                "actions": [],
+                "actionMatch": "all",
+            }
+        )
+        result = serialize(
+            [alert_rule, issue_rule],
+            serializer=CombinedRuleSerializer(),
+        )
+        assert mock_logger.exception.call_count == 1
+        self.assert_alert_rule_serialized(alert_rule, result[0])
+        # we have limited data here because of the exception
+        assert result[1] == {"type": "rule"}
+
     def test_alert_snoozed(self) -> None:
         projects = [self.project, self.create_project()]
         alert_rule = self.create_alert_rule(projects=projects)