fix(replication): fan out single-bucket rules to all targets (#2701)

crates/ecstore/src/bucket/replication/config.rs

@@ -224,19 +224,98 @@ impl ReplicationConfigurationExt for ReplicationConfiguration {
                 continue;
             }
 
-            if !self.role.is_empty() {
-                arns.push(self.role.clone()); // Use the legacy RoleArn when present
-                return arns;
-            }
-
-            if !targets_map.contains(&rule.destination.bucket) {
+            if !rule.destination.bucket.is_empty() && !targets_map.contains(&rule.destination.bucket) {
                 targets_map.insert(rule.destination.bucket.clone());
             }
         }
 
+        if targets_map.is_empty() && !self.role.is_empty() {
+            arns.push(self.role.clone());
+            return arns;
+        }
+
         for arn in targets_map {
             arns.push(arn);
         }
         arns
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use s3s::dto::{DeleteMarkerReplication, Destination, ExistingObjectReplication, ReplicationRule};
+
+    fn replication_rule(id: &str, arn: &str) -> ReplicationRule {
+        ReplicationRule {
+            delete_marker_replication: Some(DeleteMarkerReplication::default()),
+            delete_replication: None,
+            destination: Destination {
+                bucket: arn.to_string(),
+                ..Default::default()
+            },
+            existing_object_replication: Some(ExistingObjectReplication {
+                status: ExistingObjectReplicationStatus::from_static(ExistingObjectReplicationStatus::ENABLED),
+            }),
+            filter: None,
+            id: Some(id.to_string()),
+            prefix: Some(String::new()),
+            priority: Some(1),
+            source_selection_criteria: None,
+            status: ReplicationRuleStatus::from_static(ReplicationRuleStatus::ENABLED),
+        }
+    }
+
+    #[test]
+    fn filter_target_arns_keeps_multiple_destinations_when_role_is_present() {
+        let config = ReplicationConfiguration {
+            role: "arn:legacy:target".to_string(),
+            rules: vec![
+                replication_rule("rule-1", "arn:target:a"),
+                replication_rule("rule-2", "arn:target:b"),
+            ],
+        };
+
+        let arns = config.filter_target_arns(&ObjectOpts {
+            name: "object".to_string(),
+            op_type: ReplicationType::Object,
+            ..Default::default()
+        });
+
+        assert_eq!(arns.len(), 2);
+        assert!(arns.iter().any(|arn| arn == "arn:target:a"));
+        assert!(arns.iter().any(|arn| arn == "arn:target:b"));
+    }
+
+    #[test]
+    fn filter_target_arns_falls_back_to_role_when_destination_is_empty() {
+        let config = ReplicationConfiguration {
+            role: "arn:legacy:target".to_string(),
+            rules: vec![ReplicationRule {
+                delete_marker_replication: Some(DeleteMarkerReplication::default()),
+                delete_replication: None,
+                destination: Destination {
+                    bucket: String::new(),
+                    ..Default::default()
+                },
+                existing_object_replication: Some(ExistingObjectReplication {
+                    status: ExistingObjectReplicationStatus::from_static(ExistingObjectReplicationStatus::ENABLED),
+                }),
+                filter: None,
+                id: Some("rule-1".to_string()),
+                prefix: Some(String::new()),
+                priority: Some(1),
+                source_selection_criteria: None,
+                status: ReplicationRuleStatus::from_static(ReplicationRuleStatus::ENABLED),
+            }],
+        };
+
+        let arns = config.filter_target_arns(&ObjectOpts {
+            name: "object".to_string(),
+            op_type: ReplicationType::Object,
+            ..Default::default()
+        });
+
+        assert_eq!(arns, vec!["arn:legacy:target".to_string()]);
+    }
+}