fix setting of missing time stamps while reading.

lib/src/kdbx_times.dart

@@ -5,6 +5,10 @@ import 'package:kdbx/src/kdbx_xml.dart';
 import 'package:quiver/iterables.dart';
 import 'package:xml/xml.dart';
 
+import 'package:logging/logging.dart';
+
+final _logger = Logger('kdbx_times');
+
 class KdbxTimes extends KdbxNode implements KdbxNodeContext {
   KdbxTimes.create(this.ctx) : super.create('Times') {
     final now = clock.now().toUtc();
@@ -16,15 +20,32 @@ class KdbxTimes extends KdbxNode implements KdbxNodeContext {
     usageCount.set(0);
     locationChanged.set(now);
   }
-  KdbxTimes.read(XmlElement node, this.ctx) : super.read(node);
+  KdbxTimes.read(XmlElement node, this.ctx) : super.read(node) {
+    // backward compatibility - there was a bug setting/reading
+    // modification, lastAccess and expiryTime. Make sure they are defined.
+    final checkDates = {
+      lastModificationTime: () => creationTime.get() ?? clock.now().toUtc(),
+      lastAccessTime: () => lastModificationTime.get() ?? clock.now().toUtc(),
+      expiryTime: () {
+        expires.set(false);
+        return clock.now().toUtc();
+      },
+    };
+    for (final check in checkDates.entries) {
+      if (check.key.get() == null) {
+        final val = check.value();
+        _logger.warning('${check.key.name} was not defined. setting to $val');
+        check.key.set(val);
+      }
+    }
+  }
 
   @override
   final KdbxReadWriteContext ctx;
 
   DateTimeUtcNode get creationTime => DateTimeUtcNode(this, 'CreationTime');
   DateTimeUtcNode get lastModificationTime =>
-      DateTimeUtcNode(this, 'LastModificationTime',
-          defaultValue: () => creationTime.get() ?? DateTimeUtcNode.minDate);
+      DateTimeUtcNode(this, 'LastModificationTime');
   DateTimeUtcNode get lastAccessTime => DateTimeUtcNode(this, 'LastAccessTime');
   DateTimeUtcNode get expiryTime => DateTimeUtcNode(this, 'ExpiryTime');
   BooleanNode get expires => BooleanNode(this, 'Expires');

lib/src/kdbx_xml.dart

@@ -231,11 +231,9 @@ class BooleanNode extends KdbxSubTextNode<bool> {
 }
 
 class DateTimeUtcNode extends KdbxSubTextNode<DateTime> {
-  DateTimeUtcNode(KdbxNodeContext node, String name, {this.defaultValue})
-      : super(node, name);
+  DateTimeUtcNode(KdbxNodeContext node, String name) : super(node, name);
 
   static const EpochSeconds = 62135596800;
-  final DateTime Function() defaultValue;
 
   KdbxReadWriteContext get _ctx => (node as KdbxNodeContext).ctx;
   static final minDate = DateTime.fromMillisecondsSinceEpoch(0, isUtc: true);
@@ -250,7 +248,7 @@ class DateTimeUtcNode extends KdbxSubTextNode<DateTime> {
   @override
   DateTime decode(String value) {
     if (value == null) {
-      return defaultValue?.call();
+      return null;
     }
     if (value.contains(':')) {
       return DateTime.parse(value);