Merge 546edd21ef into a1bdf76412

server/src/main/java/com/vaadin/ui/Grid.java

@@ -5061,7 +5061,7 @@ public class Grid<T> extends AbstractListing<T> implements HasComponents,
 
     @Override
     protected void internalSetDataProvider(DataProvider<T, ?> dataProvider) {
-        boolean newProvider = getDataProvider() != dataProvider;
+        boolean newProvider = internalGetDataProvider() != dataProvider;
         super.internalSetDataProvider(dataProvider);
         if (newProvider) {
             Set<T> oldVisibleDetails = new HashSet<>(

server/src/test/java/com/vaadin/tests/components/grid/GridOverrideDataProviderGetterTest.java

@@ -0,0 +1,74 @@
+package com.vaadin.tests.components.grid;
+
+import com.vaadin.data.provider.ListDataProvider;
+import com.vaadin.ui.Grid;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+public class GridOverrideDataProviderGetterTest
+{
+    private ListDataProvider<MyBean> listDataProvider;
+
+    @Before
+    public void setUp()
+    {
+        MyBean myBean1 = new MyBean("name1");
+        MyBean myBean2 = new MyBean("name2");
+        listDataProvider = new ListDataProvider<>(Arrays.asList(myBean1,myBean2));
+    }
+
+    /**
+     * Originally calling the constructor of MyGrid will throw:
+     * <pre>
+     * java.lang.ClassCastException: class com.vaadin.data.provider.CallbackDataProvider cannot be cast to class com.vaadin.data.provider.ListDataProvider (com.vaadin.data.provider.CallbackDataProvider and com.vaadin.data.provider.ListDataProvider are in unnamed module of loader 'app')
+     * </pre>
+     * Don't call an overridable method in your constructor is the moral of the story
+     */
+    @Test
+    public void testCalling()
+    {
+        try {
+            Grid<MyBean> grid = new MyGrid<>(listDataProvider);
+            assertTrue(grid.getDataProvider() instanceof ListDataProvider);
+        } catch(ClassCastException e) {
+            fail("Should not throw a ClassCastException error:" + e);
+        }
+    }
+
+    private static class MyGrid<T> extends Grid<T>
+    {
+        public MyGrid(ListDataProvider<T> myDataProvider)
+        {
+            super(myDataProvider);
+        }
+
+        /**
+         * I'm overriding this because I can
+         */
+        @Override
+        public ListDataProvider<T> getDataProvider()
+        {
+            return (ListDataProvider<T>) super.getDataProvider();
+        }
+    }
+
+    private static class MyBean
+    {
+        private final String name;
+
+        MyBean(String name)
+        {
+            this.name = name;
+        }
+
+        public String getName()
+        {
+            return name;
+        }
+    }
+}