regression of Creator check, #20537 (#20538)

* try to reproduce the regression of Creator check, #20537

* fix regression of Creator check, #20537

* the check of the enclosing class parameter should check the first parameter

akka-actor-tests/src/test/java/akka/actor/ActorCreationTest.java

@@ -5,6 +5,10 @@
 package akka.actor;
 
 import static org.junit.Assert.*;
+import static java.util.stream.Collectors.toCollection;
+
+import java.util.ArrayList;
+import java.util.stream.IntStream;
 
 import akka.testkit.TestActors;
 import org.junit.Test;
@@ -144,6 +148,30 @@ public class ActorCreationTest extends JUnitSuite {
     }
   }
 
+  public static class Issue20537Reproducer extends UntypedActor {
+
+    static final class ReproducerCreator implements Creator<Issue20537Reproducer> {
+
+      final boolean create;
+
+      private ReproducerCreator(boolean create) {
+        this.create = create;
+      }
+
+      @Override
+      public Issue20537Reproducer create() throws Exception {
+        return new Issue20537Reproducer(create);
+      }
+    }
+
+    public Issue20537Reproducer(boolean create) {
+    }
+
+    @Override
+    public void onReceive(Object message) throws Exception {
+    }
+  }
+
   @Test
   public void testWrongAnonymousInPlaceCreator() {
     try {
@@ -287,5 +315,18 @@ public class ActorCreationTest extends JUnitSuite {
     assertEquals(UntypedTestActor.class, p.actorClass());
   }
 
+  @Test
+  public void testIssue20537Reproducer() {
+    final Issue20537Reproducer.ReproducerCreator creator = new Issue20537Reproducer.ReproducerCreator(false);
+    final Props p = Props.create(creator);
+    assertEquals(Issue20537Reproducer.class, p.actorClass());
+
+    ArrayList<Props> pList = IntStream.range(0, 4).mapToObj(i -> Props.create(creator))
+        .collect(toCollection(ArrayList::new));
+    for (Props each : pList) {
+      assertEquals(Issue20537Reproducer.class, each.actorClass());
+    }
+  }
+
 
 }

akka-actor/src/main/scala/akka/actor/AbstractProps.scala

@@ -87,7 +87,7 @@ private[akka] trait AbstractProps {
         if (i == declaredConstructors.length) false
         else {
           val c = declaredConstructors(i)
-          if (c.getParameterCount >= 1 && c.getParameterTypes()(i) == enclosingClass)
+          if (c.getParameterCount >= 1 && c.getParameterTypes()(0) == enclosingClass)
             true
           else
             loop(i + 1) // recur