Made nullable sentinel static

Author: kerberjg

packages/crystallis/lib/runtime/mixin.dart

@@ -4,6 +4,9 @@ import 'package:meta/meta.dart';
 import 'field_metadata.dart';
 import 'validator.dart';
 
+/// Sentinel value used to represent true nullability in [copyWith] parameters.
+enum _NullableSentinel { i }
+
 /// Mixin class that provides validation functionality for data classes.
 /// Applied to classes generated with [Crystallise].
 abstract mixin class CrystallisData {
@@ -14,6 +17,11 @@ abstract mixin class CrystallisData {
   @protected
   Crystallise get config;
 
+  /// Nullable value sentinel used in generated [copyWith] methods.
+  @protected
+  // ignore: library_private_types_in_public_api
+  static const _NullableSentinel nullValue = _NullableSentinel.i;
+
   /// Get the value of a field by name.
   /// To see what type it might be, check [metadata].
   ///

packages/crystallis_generator/lib/crystallis_generator.dart

@@ -109,11 +109,6 @@ class CrystallisGenerator extends GeneratorForAnnotation<Crystallise> {
       buffer.writeln();
     }
 
-    if (enableCopyWith) {
-      buffer.writeln('enum _Sentinel { i }');
-      buffer.writeln();
-    }
-
     // class declaration
     if (!mutable) {
       buffer.writeln("@immutable");
@@ -323,12 +318,12 @@ class CrystallisGenerator extends GeneratorForAnnotation<Crystallise> {
       var objectQuestionType = element.library.typeProvider.objectQuestionType;
       var objectType = element.library.typeProvider.objectType;
       for (final f in fields) {
-        buffer.write('${f.type.isNullable ? objectQuestionType : objectType} ${f.name} = _Sentinel.i,');
+        buffer.write('${f.type.isNullable ? objectQuestionType : objectType} ${f.name} = CrystallisData.nullValue,');
       }
       buffer.writeln('}) => $publicName(');
       for (final f in fields) {
         var prefix = ' ' * 6;
-        buffer.write('$prefix${f.name}: ${f.name} == _Sentinel.i');
+        buffer.write('$prefix${f.name}: ${f.name} == CrystallisData.nullValue');
         if (useDeepCopy && (f.type.isDartCoreList || f.type.isDartCoreSet || f.type.isDartCoreMap)) {
           final bool curly = !f.type.isDartCoreList;
           String open = curly ? '{' : '[';

packages/crystallis_generator/test/generated_golden.test.dart

@@ -398,8 +398,8 @@ void main() {
     final generated = outputs['$outputPackage|lib/user.data.g.dart']!;
     expect(generated, contains('UserData Function({'));
     expect(generated, contains('}) get copyWith =>'));
-    expect(generated, contains('Object friends = _Sentinel.i'));
-    expect(generated, contains('friends: friends == _Sentinel.i'));
+    expect(generated, contains('Object friends = CrystallisData.nullValue'));
+    expect(generated, contains('friends: friends == CrystallisData.nullValue'));
     expect(generated, contains('this.friends'));
     expect(generated, isNot(contains('...this.friends')));
     expect(generated, contains('friends as List<String>'));
@@ -417,8 +417,8 @@ void main() {
     final generated = outputs['$outputPackage|lib/user.data.g.dart']!;
     expect(generated, contains('UserData Function({'));
     expect(generated, contains('}) get copyWith =>'));
-    expect(generated, contains('Object friends = _Sentinel.i'));
-    expect(generated, contains('friends: friends == _Sentinel.i'));
+    expect(generated, contains('Object friends = CrystallisData.nullValue'));
+    expect(generated, contains('friends: friends == CrystallisData.nullValue'));
     expect(generated, contains('[...this.friends]'));
     expect(generated, contains('[...friends as List<String>]'));
   });