Don't reset date to current at DateField state (e.g. read-only) updates. (#11879)

- DateFields with month or year resolution should not get their date
reset to current date if the field's state is updated (e.g. by changing
read-only status or adding a range).

Fixes: #11864, #11605

client/src/main/java/com/vaadin/client/ui/VAbstractCalendarPanel.java

@@ -16,6 +16,8 @@
 
 package com.vaadin.client.ui;
 
+import static com.vaadin.client.DateTimeService.asTwoDigits;
+
 import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
@@ -30,7 +32,6 @@ import com.google.gwt.aria.client.Roles;
 import com.google.gwt.aria.client.SelectedValue;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.NativeEvent;
-import com.google.gwt.dom.client.Style;
 import com.google.gwt.event.dom.client.BlurEvent;
 import com.google.gwt.event.dom.client.BlurHandler;
 import com.google.gwt.event.dom.client.ClickHandler;
@@ -56,14 +57,11 @@ import com.google.gwt.user.client.ui.Button;
 import com.google.gwt.user.client.ui.FlexTable;
 import com.google.gwt.user.client.ui.InlineHTML;
 import com.google.gwt.user.client.ui.Widget;
-import com.vaadin.client.BrowserInfo;
 import com.vaadin.client.DateTimeService;
 import com.vaadin.client.WidgetUtil;
 import com.vaadin.client.ui.aria.AriaHelper;
 import com.vaadin.shared.util.SharedUtil;
 
-import static com.vaadin.client.DateTimeService.asTwoDigits;
-
 /**
  * Abstract calendar panel to show and select a date using a resolution. The
  * class is parameterized by the date resolution enumeration type.
@@ -963,7 +961,17 @@ public abstract class VAbstractCalendarPanel<R extends Enum<R>>
      *            resolution of the calendar is changed and no date has been
      *            selected.
      */
+    @SuppressWarnings("rawtypes")
     public void renderCalendar(boolean updateDate) {
+        if (parent instanceof VAbstractPopupCalendar
+                && !((VAbstractPopupCalendar) parent).popup.isShowing()) {
+            if (getDate() == null) {
+                // no date set, cannot pre-render yet
+                return;
+            }
+            // a popup that isn't open cannot possibly need a focus change event
+            updateDate = false;
+        }
         doRenderCalendar(updateDate);
 
         initialRenderDone = true;
@@ -986,11 +994,15 @@ public abstract class VAbstractCalendarPanel<R extends Enum<R>>
                 getDateField().getStylePrimaryName() + "-calendarpanel");
 
         if (focusedDate == null) {
-            Date now = new Date();
+            Date date = getDate();
+            if (date == null) {
+                date = new Date();
+            }
             // focusedDate must have zero hours, mins, secs, millisecs
-            focusedDate = new FocusedDate(now.getYear(), now.getMonth(),
-                    now.getDate());
-            displayedMonth = new FocusedDate(now.getYear(), now.getMonth(), 1);
+            focusedDate = new FocusedDate(date.getYear(), date.getMonth(),
+                    date.getDate());
+            displayedMonth = new FocusedDate(date.getYear(), date.getMonth(),
+                    1);
         }
 
         if (updateDate && !isDay(getResolution())

uitest/src/main/java/com/vaadin/tests/components/datefield/DateFieldMonthResolutionStatusChange.java

@@ -0,0 +1,49 @@
+package com.vaadin.tests.components.datefield;
+
+import java.time.LocalDate;
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.shared.ui.datefield.DateResolution;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.DateField;
+
+public class DateFieldMonthResolutionStatusChange extends AbstractTestUI {
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        DateField dateField = new DateField();
+        dateField.setResolution(DateResolution.MONTH);
+        dateField.setValue(LocalDate.of(2019, 1, 1));
+        dateField.setReadOnly(true);
+
+        Button dateReadOnlySwitch = new Button("Toggle read-only");
+        dateReadOnlySwitch.setId("readOnly");
+        dateReadOnlySwitch.addClickListener(event -> {
+            dateField.setReadOnly(!dateField.isReadOnly());
+        });
+
+        Button addRangeButton = new Button("Add range");
+        addRangeButton.setId("addRange");
+        addRangeButton.addClickListener(event -> {
+            dateField.setRangeStart(LocalDate.of(2018, 1, 1));
+            dateField.setRangeEnd(LocalDate.of(2020, 1, 1));
+        });
+
+        addComponent(dateField);
+        addComponent(dateReadOnlySwitch);
+        addComponent(addRangeButton);
+    }
+
+    @Override
+    protected String getTestDescription() {
+        return "Changing any field status (e.g. read-only or range) before "
+                + "the DateField popup has been opened should not change "
+                + "the date to current.";
+    }
+
+    @Override
+    protected Integer getTicketNumber() {
+        return 11864;
+    }
+}

uitest/src/test/java/com/vaadin/tests/components/datefield/DateFieldMonthResolutionStatusChangeTest.java

@@ -0,0 +1,38 @@
+package com.vaadin.tests.components.datefield;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.vaadin.testbench.elements.ButtonElement;
+import com.vaadin.testbench.elements.DateFieldElement;
+import com.vaadin.tests.tb3.MultiBrowserTest;
+
+public class DateFieldMonthResolutionStatusChangeTest
+        extends MultiBrowserTest {
+
+    @Test
+    public void testChangeReadOnly() {
+        openTestURL();
+        DateFieldElement df = $(DateFieldElement.class).first();
+        assertEquals("Unexpected initial date.", "1/19", df.getValue());
+
+        // switch read-only state
+        $(ButtonElement.class).id("readOnly").click();
+
+        assertEquals("Unexpected date change.", "1/19", df.getValue());
+    }
+
+    @Test
+    public void testAddRange() {
+        openTestURL();
+        DateFieldElement df = $(DateFieldElement.class).first();
+        assertEquals("Unexpected initial date.", "1/19", df.getValue());
+
+        // add range
+        $(ButtonElement.class).id("addRange").click();
+
+        assertEquals("Unexpected date change.", "1/19", df.getValue());
+    }
+
+}