fix Stalwart Successor checking permanents entering

Mage.Sets/src/mage/cards/s/StalwartSuccessor.java

@@ -78,14 +78,19 @@ class StalwartSuccessorTriggeredAbility extends TriggeredAbilityImpl {
 
     @Override
     public boolean checkTrigger(GameEvent event, Game game) {
+        int zccOffset = 0;
         Permanent permanent = game.getPermanent(event.getTargetId());
+        if (permanent == null) {
+            permanent = game.getPermanentEntering(event.getTargetId());
+            zccOffset = 1;
+        }
         if (permanent == null
                 || !permanent.isCreature(game)
                 || !permanent.isControlledBy(getControllerId())
                 || !StalwartSuccessorWatcher.checkCreature(permanent, event, game)) {
             return false;
         }
-        this.getEffects().setTargetPointer(new FixedTarget(permanent, game));
+        this.getEffects().setTargetPointer(new FixedTarget(permanent.getId(), permanent.getZoneChangeCounter(game) + zccOffset));
         return true;
     }
 }
@@ -101,6 +106,11 @@ class StalwartSuccessorWatcher extends Watcher {
     @Override
     public void watch(GameEvent event, Game game) {
         if (event.getType() == GameEvent.EventType.COUNTERS_ADDED) {
+            if (game.getPermanent(event.getTargetId()) == null) {
+                // permanent entering
+                Permanent permanent = game.getPermanentEntering(event.getTargetId());
+                map.putIfAbsent(new MageObjectReference(event.getTargetId(), permanent.getZoneChangeCounter(game) + 1, game), event.getId());
+            }
             map.putIfAbsent(new MageObjectReference(event.getTargetId(), game), event.getId());
         }
     }

Mage.Tests/src/test/java/org/mage/test/cards/single/tdm/StalwartSuccessorTest.java

@@ -0,0 +1,48 @@
+package org.mage.test.cards.single.tdm;
+
+import mage.constants.PhaseStep;
+import mage.constants.Zone;
+import mage.counters.CounterType;
+import org.junit.Test;
+import org.mage.test.serverside.base.CardTestPlayerBase;
+
+public class StalwartSuccessorTest extends CardTestPlayerBase {
+
+    /*
+    Stalwart Successor
+    {1}{B}{G}
+    Creature — Human Warrior
+
+    Menace (This creature can’t be blocked except by two or more creatures.)
+
+    Whenever one or more counters are put on a creature you control, if it’s the first time counters have been put on that creature this turn, put a +1/+1 counter on that creature.
+
+    3/2
+     */
+    private static final String stalwartSuccessor = "Stalwart Successor";
+    /*
+    Purestrain Genestealer
+    {2}{G}
+    Creature — Tyranid
+
+    This creature enters with two +1/+1 counters on it.
+
+    Vanguard Species — Whenever this creature attacks, you may remove a +1/+1 counter from it. If you do, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
+
+    1/1
+     */
+    private static final String purestrainGenestealer = "Purestrain Genestealer";
+    @Test
+    public void testStalwartSuccessor() {
+
+        addCard(Zone.BATTLEFIELD, playerA, stalwartSuccessor);
+        addCard(Zone.BATTLEFIELD, playerA, "Forest", 3);
+        addCard(Zone.HAND, playerA, purestrainGenestealer);
+
+        castSpell(1, PhaseStep.PRECOMBAT_MAIN, playerA, purestrainGenestealer);
+        setStopAt(1, PhaseStep.END_TURN);
+        execute();
+
+        assertCounterCount(playerA, purestrainGenestealer, CounterType.P1P1, 2 + 1);
+    }
+}