[gnome-contacts] Ensure correct handling of February 2000 in birthday editor

[Niels De Graef <nielsdg src gnome org>]

commit 5350ec53ae7241b372a54bbfb8a8d0e224bab6fd
Author: Charles Keepax <ckeepax gmail com>
Date:   Tue Sep 21 21:32:19 2021 +0100

    Ensure correct handling of February 2000 in birthday editor
    
    There is a third rule for leap year handling which is that years
    divisible by 400 are leap years. Normally this isn't a huge issue since
    it only happens every 400 years, but the year 2000 was one of those
    years which is well within the reasonable range of current birthdays and
    the current system will not accept the 29th of February 2000 as a valid
    date.

 src/contacts-editor-property.vala | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/src/contacts-editor-property.vala b/src/contacts-editor-property.vala
index 14fa933f..d03cde3b 100644
--- a/src/contacts-editor-property.vala
+++ b/src/contacts-editor-property.vala
@@ -104,8 +104,9 @@ public class Contacts.BirthdayEditor : Gtk.Dialog {
       if (month_combo.get_active () in month_of_31) {
         day_spin.set_range (1, 30);
       } else if (month_combo.get_active () == 1) {
-        if (year_spin.get_value_as_int () % 4 == 0 &&
-            year_spin.get_value_as_int () % 100 != 0) {
+        if (year_spin.get_value_as_int () % 400 == 0 ||
+            (year_spin.get_value_as_int () % 4 == 0 &&
+             year_spin.get_value_as_int () % 100 != 0)) {
           day_spin.set_range (1, 29);
         } else {
           day_spin.set_range (1, 28);