[fix](nereids) fix bug in PhysicalTopN.equals() (#46547)

Author: englefly

Diff for: fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/physical/PhysicalTopN.java

@@ -93,7 +93,9 @@ public boolean equals(Object o) {
             return false;
         }
         PhysicalTopN<?> that = (PhysicalTopN<?>) o;
-        return limit == that.limit && offset == that.offset;
+        return limit == that.limit && offset == that.offset
+                && this.phase == that.phase
+                && Objects.equals(that.getOrderKeys(), getOrderKeys());
     }
 
     @Override

Diff for: fe/fe-core/src/test/java/org/apache/doris/nereids/trees/plans/physical/PhysicalTopNTest.java

@@ -0,0 +1,55 @@
+// 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.doris.nereids.trees.plans.physical;
+
+import org.apache.doris.nereids.properties.OrderKey;
+import org.apache.doris.nereids.trees.expressions.ExprId;
+import org.apache.doris.nereids.trees.expressions.SlotReference;
+import org.apache.doris.nereids.trees.plans.Plan;
+import org.apache.doris.nereids.trees.plans.SortPhase;
+import org.apache.doris.nereids.types.BigIntType;
+
+import com.google.common.collect.Lists;
+import mockit.Mocked;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+public class PhysicalTopNTest {
+    @Test
+    public void testEquals(@Mocked Plan child) {
+        SlotReference a = new SlotReference(new ExprId(0), "a",
+                BigIntType.INSTANCE, true, Lists.newArrayList());
+        List<OrderKey> orderKeysA = Lists.newArrayList();
+        orderKeysA.add(new OrderKey(a, true, true));
+        PhysicalTopN topn1 = new PhysicalTopN(orderKeysA, 1, 1, SortPhase.LOCAL_SORT,
+                null, child);
+        PhysicalTopN topn2 = new PhysicalTopN(orderKeysA, 1, 1, SortPhase.GATHER_SORT,
+                null, child);
+        Assertions.assertNotEquals(topn1, topn2);
+
+        SlotReference b = new SlotReference(new ExprId(0), "b",
+                BigIntType.INSTANCE, true, Lists.newArrayList());
+        List<OrderKey> orderKeysB = Lists.newArrayList();
+        orderKeysB.add(new OrderKey(b, true, true));
+        PhysicalTopN topn3 = new PhysicalTopN(orderKeysB, 1, 1, SortPhase.LOCAL_SORT,
+                null, child);
+        Assertions.assertNotEquals(topn2, topn3);
+    }
+}