moved due date check to task.dart

lib/components/BucketTaskCard.dart

@@ -99,7 +99,7 @@ class _BucketTaskCardState extends State<BucketTaskCard> with AutomaticKeepAlive
         ),
       ],
     );
-    if (widget.task.dueDate.year > 2) {
+    if (widget.task.hasDueDate) {
       final duration = widget.task.dueDate.difference(DateTime.now());
       final pastDue = duration.isNegative && !widget.task.done;
       titleRow.children.add(Container(

lib/components/TaskTile.dart

@@ -77,7 +77,7 @@ class TaskTileState extends State<TaskTile> with AutomaticKeepAliveClientMixin {
           ) : Text(_currentTask.title),
       controlAffinity: ListTileControlAffinity.leading,
       value: _currentTask.done ?? false,
-      subtitle: widget.showInfo && _currentTask.dueDate.year > 2 ?
+      subtitle: widget.showInfo && _currentTask.hasDueDate ?
           Text("Due " + durationToHumanReadable(durationUntilDue), style: TextStyle(color: durationUntilDue.isNegative ? Colors.red : null),)
           : _currentTask.description == null || _currentTask.description.isEmpty
               ? null

lib/models/task.dart

@@ -141,6 +141,8 @@ class Task {
       return false;
   }
 
+  bool get hasDueDate => dueDate.year != 1;
+
   Task copyWith({
     int id, int parentTaskId, int priority, int listId, int bucketId,
     DateTime created, DateTime updated, DateTime dueDate, DateTime startDate, DateTime endDate,