[datetime] fix(DRP): right cal shows correct month when clicking shortcut (#4066)

Fixed: Incorrect selection of years on right side when clicking through years on shortcuts while contiguousCalendarMonths=false

Co-authored-by: Sergey Chopchyts <[email protected]>

Author: schopchyts

packages/datetime/src/dateRangePicker.tsx

@@ -704,7 +704,7 @@ function getStateChange(
             // If the selected month isn't in either of the displayed months, then
             //   - set the left DayPicker to be the selected month
             //   - set the right DayPicker to +1
-            if (nextValueStartView.isSameMonth(nextValueEndView)) {
+            if (nextValueStartView.isSame(nextValueEndView)) {
                 if (leftView.isSame(nextValueStartView) || rightView.isSame(nextValueStartView)) {
                     // do nothing
                 } else {

packages/datetime/test/dateRangePickerTests.tsx

@@ -1018,6 +1018,24 @@ describe("<DateRangePicker>", () => {
             left.assertMonthYear(Months.JANUARY, 2016);
             right.assertMonthYear(Months.FEBRUARY, 2016);
         });
+
+        it("custom shortcuts set the displayed dates correctly when month stays the same but not years and contiguousCalendarMonths is false", () => {
+            const dateRange = [new Date(2014, Months.JUNE, 1), new Date(2015, Months.JUNE, 1)] as DateRange;
+            const { clickShortcut, left, right } = render({
+                contiguousCalendarMonths: false,
+                initialMonth: new Date(2015, Months.JUNE, 1),
+                shortcuts: [{ label: "custom shortcut", dateRange }],
+            });
+
+            clickShortcut();
+            assert.isTrue(onChangeSpy.calledOnce);
+            left.assertMonthYear(Months.JUNE, 2014);
+            right.assertMonthYear(Months.JUNE, 2015);
+
+            clickShortcut();
+            left.assertMonthYear(Months.JUNE, 2014);
+            right.assertMonthYear(Months.JUNE, 2015);
+        });
     });
 
     describe("when uncontrolled", () => {