LMOVing a list element to same list should not remove the element. (#…

…1047)

* Keep the element with LMOVing a list element to itself.

* Break earlier to avoid unneceesary actions.

---------

Co-authored-by: prvyk <[email protected]>
Co-authored-by: Tal Zaccai <[email protected]>

libs/server/Storage/Session/ObjectStore/ListOps.cs

@@ -260,6 +260,15 @@ public GarnetStatus ListMove(ArgSlice sourceKey, ArgSlice destinationKey, Operat
 
                         dstListObject = listObject;
                     }
+                    else // sameKey
+                    {
+                        if (sourceDirection == destinationDirection)
+                        {
+                            element = (sourceDirection == OperationDirection.Right) ?
+                                        srcListObject.LnkList.Last.Value : srcListObject.LnkList.First.Value;
+                            return GarnetStatus.OK;
+                        }
+                    }
 
                     // Right pop (removelast) from source
                     if (sourceDirection == OperationDirection.Right)
@@ -299,9 +308,9 @@ public GarnetStatus ListMove(ArgSlice sourceKey, ArgSlice destinationKey, Operat
                     else
                     {
                         // When the source and the destination key is the same the operation is done only in the sourceList
-                        if (sourceDirection == OperationDirection.Right && destinationDirection == OperationDirection.Left)
+                        if (destinationDirection == OperationDirection.Left)
                             srcListObject.LnkList.AddFirst(element);
-                        else if (sourceDirection == OperationDirection.Left && destinationDirection == OperationDirection.Right)
+                        else if (destinationDirection == OperationDirection.Right)
                             srcListObject.LnkList.AddLast(element);
                         newListValue = srcListObject;
                         ((ListObject)newListValue).UpdateSize(element);

test/Garnet.test/RespListTests.cs

@@ -1169,6 +1169,7 @@ public void CanDoLMoveChunks(int bytesPerSend)
         }
 
         [Test]
+        [Category("LMOVE")]
         public void CanDoBasicLMove()
         {
             using var redis = ConnectionMultiplexer.Connect(TestUtils.GetConfig());
@@ -1193,13 +1194,25 @@ public void CanDoBasicLMove()
             ClassicAssert.AreEqual(key1Values[0], result);
 
             var members = db.ListRange(key2);
-            ClassicAssert.AreEqual(key1Values.Union(key2Values).ToArray(), members);
+            var keys = key1Values.Union(key2Values).ToArray();
+            ClassicAssert.AreEqual(keys, members);
+
+            result = db.ListMove(key2, key2, ListSide.Right, ListSide.Right);
+            ClassicAssert.AreEqual(key2Values[0], result);
+
+            members = db.ListRange(key2);
+            ClassicAssert.AreEqual(keys, members);
+
+            result = db.ListMove(key2, key2, ListSide.Left, ListSide.Left);
+            ClassicAssert.AreEqual(key1Values[0], result);
+
+            members = db.ListRange(key2);
+            ClassicAssert.AreEqual(keys, members);
 
             var exists = db.KeyExists(key1);
             ClassicAssert.IsFalse(exists);
         }
 
-
         [Test]
         public void CanDoLPopMultipleValues()
         {