Add Value.absentIfNull

Author: simolus3

drift/CHANGELOG.md

@@ -12,6 +12,8 @@
 - Improve stack traces for errors happening on drift isolates (which includes
   usages of `NativeDatabase.createInBackground`).
 - Don't cache `EXPLAIN` statements, avoiding schema locks.
+- Deprecate `Value.ofNullable` in favor of `Value.absentIfNull`, which is more
+  explicit about its behavior and allows nullable types too.
 - Migrate `WasmDatabase` to `dart:js_interop` and `package:web`.
 
 ## 2.15.0

drift/lib/src/runtime/data_class.dart

@@ -158,6 +158,7 @@ class Value<T> {
   /// This constructor should only be used when [T] is not nullable. If [T] were
   /// nullable, there wouldn't be a clear interpretation for a `null` [value].
   /// See the overall documentation on [Value] for details.
+  @Deprecated('Use Value.absentIfNull instead')
   const Value.ofNullable(T? value)
       : assert(
           value != null || null is! T,
@@ -167,6 +168,15 @@ class Value<T> {
         _value = value,
         present = value != null;
 
+  /// Create a value that is absent if [value] is `null` and [present] if it's
+  /// not.
+  ///
+  /// The functionality is equiavalent to the following:
+  /// `x != null ? Value(x) : Value.absent()`.
+  const Value.absentIfNull(T? value)
+      : _value = value,
+        present = value != null;
+
   @override
   String toString() => present ? 'Value($value)' : 'Value.absent()';
 

drift/test/database/data_class_test.dart

@@ -105,15 +105,16 @@ void main() {
     expect(entry.toCompanion(true), const PureDefaultsCompanion());
   });
 
-  test('nullable values cannot be used with nullOrAbsent', () {
+  test('utilities to wrap nullable values', () {
     expect(
-        // ignore: prefer_const_constructors
+        // ignore: prefer_const_constructors, deprecated_member_use_from_same_package
         () => Value<int?>.ofNullable(null),
         throwsA(isA<AssertionError>()));
 
-    expect(const Value<int>.ofNullable(null).present, isFalse);
-    expect(const Value<int?>.ofNullable(12).present, isTrue);
-    expect(const Value<int>.ofNullable(23).present, isTrue);
+    expect(const Value<int?>.absentIfNull(null).present, isFalse);
+    expect(const Value<int>.absentIfNull(null).present, isFalse);
+    expect(const Value<int?>.absentIfNull(12).present, isTrue);
+    expect(const Value<int>.absentIfNull(23).present, isTrue);
   });
 
   test('companions support hash and equals', () {