Fix Address ordering bug (#1562) (#1565)

Co-authored-by: sadekmunawar <76756708+sadekmunawar@users.noreply.github.com>
Co-authored-by: Sadek Munawar <musadek@amazon.com>

actor-tests/src/test/scala/org/apache/pekko/actor/AddressSpec.scala

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.pekko.actor
+
+import org.apache.pekko.testkit.PekkoSpec
+
+class AddressSpec extends PekkoSpec {
+  "Address ordering" must {
+
+    "work correctly with multiple mixed protocols" in {
+      val pekkoAddress1 = Address("pekko", "system", "host1", 1000)
+      val pekkoAddress2 = Address("pekko", "system", "host2", 1000)
+      val akkaAddress1 = Address("akka", "system", "host1", 1000)
+      val akkaAddress2 = Address("akka", "system", "host2", 1000)
+
+      val addresses = Seq(pekkoAddress1, pekkoAddress2, akkaAddress1, akkaAddress2)
+      val sortedAddresses = addresses.sorted
+
+      sortedAddresses should ===(Seq(akkaAddress1, akkaAddress2, pekkoAddress1, pekkoAddress2))
+    }
+  }
+}

actor/src/main/scala/org/apache/pekko/actor/Address.scala

@@ -136,7 +136,7 @@ object Address {
    */
   implicit val addressOrdering: Ordering[Address] = Ordering.fromLessThan[Address] { (a, b) =>
     if (a eq b) false
-    else if (a.protocol != b.protocol) a.system.compareTo(b.protocol) < 0
+    else if (a.protocol != b.protocol) a.protocol.compareTo(b.protocol) < 0
     else if (a.system != b.system) a.system.compareTo(b.system) < 0
     else if (a.host != b.host) a.host.getOrElse("").compareTo(b.host.getOrElse("")) < 0
     else if (a.port != b.port) a.port.getOrElse(0) < b.port.getOrElse(0)