[#2341] Fix hasSameSlotsAs method to handle empty slots correctly

src/main/java/io/lettuce/core/cluster/models/partitions/RedisClusterNode.java

@@ -364,6 +364,10 @@ public boolean hasSameSlotsAs(RedisClusterNode other) {
             return false;
         }
 
+        if (this.slots.isEmpty() && other.slots.isEmpty()) {
+            return true;
+        }
+
         return this.slots.equals(other.slots);
     }
 

src/test/java/io/lettuce/core/cluster/models/partitions/RedisClusterNodeUnitTests.java

@@ -3,6 +3,7 @@
 import static org.assertj.core.api.Assertions.*;
 
 import java.util.Arrays;
+import java.util.List;
 
 import org.junit.jupiter.api.Test;
 
@@ -31,6 +32,46 @@ void shouldCopyNode() {
         assertThat(copy.getAliases()).contains(RedisURI.create("foo", 6379));
     }
 
+    @Test
+    void hasSameSlotsAs() {
+
+        // When both nodes have the same slots
+        RedisClusterNode nodeWithSameSlots1 = new RedisClusterNode();
+        nodeWithSameSlots1.setSlots(Arrays.asList(1, 2, 3, SlotHash.SLOT_COUNT - 1));
+
+        RedisClusterNode nodeWithSameSlots2 = new RedisClusterNode();
+        nodeWithSameSlots2.setSlots(Arrays.asList(1, 2, 3, SlotHash.SLOT_COUNT - 1));
+
+        assertThat(nodeWithSameSlots1.hasSameSlotsAs(nodeWithSameSlots2)).isTrue();
+
+        // When nodes have different slots
+        RedisClusterNode nodeWithDifferentSlots1 = new RedisClusterNode();
+        nodeWithDifferentSlots1.setSlots(Arrays.asList(1, 2, 3, SlotHash.SLOT_COUNT - 1));
+
+        RedisClusterNode nodeWithDifferentSlots2 = new RedisClusterNode();
+        nodeWithDifferentSlots2.setSlots(Arrays.asList(1, 2, 3, SlotHash.SLOT_COUNT - 2));
+
+        assertThat(nodeWithDifferentSlots1.hasSameSlotsAs(nodeWithDifferentSlots2)).isFalse();
+
+        // When both nodes' slots are empty
+        RedisClusterNode emptySlotsNode1 = new RedisClusterNode();
+        emptySlotsNode1.setSlots(List.of());
+
+        RedisClusterNode emptySlotsNode2 = new RedisClusterNode();
+        emptySlotsNode2.setSlots(List.of());
+
+        assertThat(emptySlotsNode1.hasSameSlotsAs(emptySlotsNode2)).isTrue();
+
+        // When one node's slots are empty and the other node's slots are not empty
+        RedisClusterNode oneEmptySlotsNode = new RedisClusterNode();
+        oneEmptySlotsNode.setSlots(List.of());
+
+        RedisClusterNode nonEmptySlotsNode = new RedisClusterNode();
+        nonEmptySlotsNode.setSlots(Arrays.asList(1, 2, 3));
+
+        assertThat(oneEmptySlotsNode.hasSameSlotsAs(nonEmptySlotsNode)).isFalse();
+    }
+
     @Test // considers nodeId only
     void testEquality() {