Refresh DataProvider only once when reordering the grid using GridRowDragger (#11981)

Fixes #10844

2 files changed, 25 insertions, 1 deletions

diff --git a/server/src/main/java/com/vaadin/ui/components/grid/GridRowDragger.java b/server/src/main/java/com/vaadin/ui/components/grid/GridRowDragger.java
index 56ebe406ca..6b21981f24 100644
--- a/server/src/main/java/com/vaadin/ui/components/grid/GridRowDragger.java
+++ b/server/src/main/java/com/vaadin/ui/components/grid/GridRowDragger.java
@@ -381,7 +381,11 @@ public class GridRowDragger<T> implements Serializable {
         }
 
         sourceItems.removeAll(droppedItems);
-        listDataProvider.refreshAll();
+
+        // if reordering the same grid, DataProvider's refresh will be done later
+        if (getGridDragSource().getGrid() != getGridDropTarget().getGrid()) {
+            listDataProvider.refreshAll();
+        }
     }
 
     private void handleTargetGridDrop(GridDropEvent<T> event, final int index,
diff --git a/server/src/test/java/com/vaadin/tests/server/component/grid/GridRowDraggerOneGridTest.java b/server/src/test/java/com/vaadin/tests/server/component/grid/GridRowDraggerOneGridTest.java
index 08b647cdde..6c522abcf9 100644
--- a/server/src/test/java/com/vaadin/tests/server/component/grid/GridRowDraggerOneGridTest.java
+++ b/server/src/test/java/com/vaadin/tests/server/component/grid/GridRowDraggerOneGridTest.java
@@ -128,6 +128,26 @@ public class GridRowDraggerOneGridTest {
     }
 
     @Test
+    public void listDataProvider_calledOnlyOnce() {
+
+        final int[] times = new int[1];
+
+        source.setItems("0", "1", "2");
+
+        source.getDataProvider().addDataProviderListener(ev -> times[0]++);
+
+        dragger.setDropIndexCalculator(event -> {
+            return Integer.MAX_VALUE;
+        });
+
+        drop("1", DropLocation.ABOVE, "0");
+
+        verifyDataProvider("1", "2", "0");
+
+        Assert.assertArrayEquals("DataProvider should be invoked only once", new int[] { 1 }, times);
+    }
+
+    @Test
     public void noopSourceUpdater() {
         source.setItems("0", "1", "2");