[evolution] I#1718 - ECompEditorTask: Verify Due date is after the Start date

[Milan Crha <mcrha src gnome org>]

commit 783dbb8b585feee850275c1d038d1bc36afb7978
Author: Milan Crha <mcrha redhat com>
Date:   Wed Dec 1 09:27:28 2021 +0100

    I#1718 - ECompEditorTask: Verify Due date is after the Start date
    
    Closes https://gitlab.gnome.org/GNOME/evolution/-/issues/1718

 src/calendar/gui/e-comp-editor-task.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
---
diff --git a/src/calendar/gui/e-comp-editor-task.c b/src/calendar/gui/e-comp-editor-task.c
index 262529e8c7..81ee16cb0c 100644
--- a/src/calendar/gui/e-comp-editor-task.c
+++ b/src/calendar/gui/e-comp-editor-task.c
@@ -672,6 +672,39 @@ ece_task_fill_component (ECompEditor *comp_editor,
 
        g_clear_object (&itt);
 
+       itt = e_comp_editor_property_part_datetime_get_value (E_COMP_EDITOR_PROPERTY_PART_DATETIME 
(task_editor->priv->dtstart));
+
+       if (itt && i_cal_time_is_valid_time (itt) && !i_cal_time_is_null_time (itt)) {
+               ICalTime *due;
+
+               due = e_comp_editor_property_part_datetime_get_value (E_COMP_EDITOR_PROPERTY_PART_DATETIME 
(task_editor->priv->due_date));
+
+               if (due && i_cal_time_is_valid_time (due) && !i_cal_time_is_null_time (due)) {
+                       gboolean same;
+
+                       if (i_cal_time_is_date (itt))
+                               same = i_cal_time_compare_date_only (itt, due) == 0;
+                       else
+                               same = i_cal_time_compare (itt, due) == 0;
+
+                       if (same) {
+                               e_comp_editor_set_validation_error (comp_editor,
+                                       task_editor->priv->page_general,
+                                       e_comp_editor_property_part_get_edit_widget 
(task_editor->priv->due_date),
+                                       _("Due date cannot be the same as the Start date"));
+
+                               g_clear_object (&itt);
+                               g_clear_object (&due);
+
+                               return FALSE;
+                       }
+               }
+
+               g_clear_object (&due);
+       }
+
+       g_clear_object (&itt);
+
        if (!E_COMP_EDITOR_CLASS (e_comp_editor_task_parent_class)->fill_component (comp_editor, component))
                return FALSE;