From a0f3f3d8016846cec0784bbeede3474e59fc9ac9 Mon Sep 17 00:00:00 2001
From: Isaac Adeni Adariku <isaacadariku05@gmail.com>
Date: Tue, 11 Oct 2022 12:14:52 +0100
Subject: [PATCH 1/6] Update web.md

Following this depreciated change [https://github.com/simolus3/drift/commit/1af6bb78d98ee7b57f099624619a323eafd67576#:~:text=%40Deprecated(%27Use%20the,this(executor)%3B], the documentation for the web.md needs to be updated. This PR updates the documentation to reflect the changes.
---
 docs/pages/docs/Other engines/web.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/pages/docs/Other engines/web.md b/docs/pages/docs/Other engines/web.md
index 34bf1d77..7842e96c 100644
--- a/docs/pages/docs/Other engines/web.md	
+++ b/docs/pages/docs/Other engines/web.md	
@@ -167,7 +167,7 @@ void main() {
 
   final db = WebDatabase.withStorage(DriftWebStorage.indexedDb('worker',
       migrateFromLocalStorage: false, inWebWorker: true));
-  final server = DriftServer(DatabaseConnection.fromExecutor(db));
+  final server = DriftServer(DatabaseConnection(db));
 
   self.onConnect.listen((event) {
     final msg = event as MessageEvent;
@@ -294,4 +294,4 @@ With this setup, sqlite3 can be used on the web without an external library:
 
 This snippet also works in a service worker.
 
-If you're running into any issues with the new backend, please post them [here](https://github.com/simolus3/sqlite3.dart/issues).
\ No newline at end of file
+If you're running into any issues with the new backend, please post them [here](https://github.com/simolus3/sqlite3.dart/issues).

From ba28b51125a02504ae05074534378559f0a27742 Mon Sep 17 00:00:00 2001
From: Alexander Wilde <alexander.wilde87@gmail.com>
Date: Fri, 14 Oct 2022 19:07:32 +0100
Subject: [PATCH 2/6] Decouple JsonTypeConverter from TypeConverter

---
 docs/lib/snippets/expressions.dart            |  1 -
 drift/lib/src/runtime/types/converters.dart   | 36 ++++++++++++++-----
 drift/test/generated/todos.dart               |  8 ++++-
 drift/test/generated/todos.g.dart             |  6 ++--
 drift_dev/lib/src/analyzer/dart_types.dart    |  4 +++
 drift_dev/lib/src/analyzer/helper.dart        | 13 ++++++-
 drift_dev/lib/src/model/types.dart            | 14 ++++++++
 .../lib/src/model/used_type_converter.dart    | 16 ++++++---
 .../src/writer/tables/data_class_writer.dart  |  4 +--
 .../analyzer/dart/type_converter_test.dart    |  2 +-
 10 files changed, 83 insertions(+), 21 deletions(-)

diff --git a/docs/lib/snippets/expressions.dart b/docs/lib/snippets/expressions.dart
index 43927164..6c979900 100644
--- a/docs/lib/snippets/expressions.dart
+++ b/docs/lib/snippets/expressions.dart
@@ -10,7 +10,6 @@ extension Expressions on MyDatabase {
     return (select(categories)..where((row) => hasNoTodo)).get();
   }
   // #enddocregion emptyCategories
-
 }
 
 // #docregion bitwise
diff --git a/drift/lib/src/runtime/types/converters.dart b/drift/lib/src/runtime/types/converters.dart
index 8171458b..4a362bb1 100644
--- a/drift/lib/src/runtime/types/converters.dart
+++ b/drift/lib/src/runtime/types/converters.dart
@@ -35,16 +35,20 @@ abstract class TypeConverter<D, S> {
 /// `.drift` files) refers to a type converter that inherits from
 /// [JsonTypeConverter], it will also be used for the conversion from and to
 /// JSON.
-mixin JsonTypeConverter<D, S> on TypeConverter<D, S> {
+abstract class JsonTypeConverter<D, S, J> extends TypeConverter<D, S> {
+  /// Empty constant constructor so that subclasses can have a constant
+  /// constructor.
+  const JsonTypeConverter();
+
   /// Map a value from the Data class to json.
   ///
   /// Defaults to doing the same conversion as for Dart -> SQL, [toSql].
-  S toJson(D value) => toSql(value);
+  J toJson(D value);
 
   /// Map a value from json to something understood by the data class.
   ///
   /// Defaults to doing the same conversion as for SQL -> Dart, [toSql].
-  D fromJson(S json) => fromSql(json);
+  D fromJson(J json);
 
   /// Wraps an [inner] type converter that only considers non-nullable values
   /// as a type converter that handles null values too.
@@ -52,8 +56,9 @@ mixin JsonTypeConverter<D, S> on TypeConverter<D, S> {
   /// The returned type converter will use the [inner] type converter for non-
   /// null values. Further, `null` is mapped to `null` in both directions (from
   /// Dart to SQL and vice-versa).
-  static JsonTypeConverter<D?, S?> asNullable<D, S extends Object>(
-      TypeConverter<D, S> inner) {
+  static JsonTypeConverter<D?, S?, J?>
+      asNullable<D, S extends Object, J extends Object>(
+          JsonTypeConverter<D, S, J> inner) {
     return _NullWrappingTypeConverterWithJson(inner);
   }
 }
@@ -150,9 +155,10 @@ class _NullWrappingTypeConverter<D, S extends Object>
   S requireToSql(D value) => _inner.toSql(value);
 }
 
-class _NullWrappingTypeConverterWithJson<D, S extends Object>
-    extends NullAwareTypeConverter<D, S> with JsonTypeConverter<D?, S?> {
-  final TypeConverter<D, S> _inner;
+class _NullWrappingTypeConverterWithJson<D, S extends Object, J extends Object>
+    extends NullAwareTypeConverter<D, S>
+    implements JsonTypeConverter<D?, S?, J?> {
+  final JsonTypeConverter<D, S, J> _inner;
 
   const _NullWrappingTypeConverterWithJson(this._inner);
 
@@ -161,4 +167,18 @@ class _NullWrappingTypeConverterWithJson<D, S extends Object>
 
   @override
   S requireToSql(D value) => _inner.toSql(value);
+
+  D requireFromJson(J json) => _inner.fromJson(json);
+
+  @override
+  D? fromJson(J? json) {
+    return json == null ? null : requireFromJson(json);
+  }
+
+  J? requireToJson(D? value) => _inner.toJson(value as D);
+
+  @override
+  J? toJson(D? value) {
+    return value == null ? null : requireToJson(value);
+  }
 }
diff --git a/drift/test/generated/todos.dart b/drift/test/generated/todos.dart
index 0168dbf6..dd5fdff5 100644
--- a/drift/test/generated/todos.dart
+++ b/drift/test/generated/todos.dart
@@ -135,8 +135,14 @@ class CustomConverter extends TypeConverter<MyCustomObject, String> {
 }
 
 class CustomJsonConverter extends CustomConverter
-    with JsonTypeConverter<MyCustomObject, String> {
+    implements JsonTypeConverter<MyCustomObject, String, String> {
   const CustomJsonConverter();
+
+  @override
+  MyCustomObject fromJson(String json) => fromSql(json);
+
+  @override
+  String toJson(MyCustomObject value) => toSql(value);
 }
 
 abstract class CategoryTodoCountView extends View {
diff --git a/drift/test/generated/todos.g.dart b/drift/test/generated/todos.g.dart
index 9bc1c990..a58388c1 100644
--- a/drift/test/generated/todos.g.dart
+++ b/drift/test/generated/todos.g.dart
@@ -1252,7 +1252,7 @@ class PureDefault extends DataClass implements Insertable<PureDefault> {
     serializer ??= driftRuntimeOptions.defaultSerializer;
     return PureDefault(
       txt: $PureDefaultsTable.$converter0n
-          .fromJson(serializer.fromJson<String?>(json['txt'])),
+          .fromJson(serializer.fromJson<String>(json['txt'])),
     );
   }
   factory PureDefault.fromJsonString(String encodedJson,
@@ -1373,9 +1373,9 @@ class $PureDefaultsTable extends PureDefaults
     return $PureDefaultsTable(attachedDatabase, alias);
   }
 
-  static JsonTypeConverter<MyCustomObject, String> $converter0 =
+  static JsonTypeConverter<MyCustomObject, String, String> $converter0 =
       const CustomJsonConverter();
-  static JsonTypeConverter<MyCustomObject?, String?> $converter0n =
+  static JsonTypeConverter<MyCustomObject?, String?, String?> $converter0n =
       JsonTypeConverter.asNullable($converter0);
 }
 
diff --git a/drift_dev/lib/src/analyzer/dart_types.dart b/drift_dev/lib/src/analyzer/dart_types.dart
index f3647dfb..1d33cba8 100644
--- a/drift_dev/lib/src/analyzer/dart_types.dart
+++ b/drift_dev/lib/src/analyzer/dart_types.dart
@@ -152,6 +152,8 @@ UsedTypeConverter? readTypeConverter(
   final staticType = dartExpression.staticType;
   final asTypeConverter =
       staticType != null ? helper.asTypeConverter(staticType) : null;
+  final asJsonTypeConverter =
+      staticType != null ? helper.asJsonTypeConverter(staticType) : null;
 
   if (asTypeConverter == null) {
     reportError('Not a type converter');
@@ -160,6 +162,7 @@ UsedTypeConverter? readTypeConverter(
 
   final dartType = asTypeConverter.typeArguments[0];
   final sqlType = asTypeConverter.typeArguments[1];
+  final jsonType = asJsonTypeConverter?.typeArguments[2] ?? sqlType;
 
   final typeSystem = library.typeSystem;
   final dartTypeNullable = typeSystem.isNullable(dartType);
@@ -195,6 +198,7 @@ UsedTypeConverter? readTypeConverter(
     expression: dartExpression.toSource(),
     dartType: resolvedDartType ?? DriftDartType.of(dartType),
     sqlType: sqlType,
+    jsonType: jsonType,
     dartTypeIsNullable: dartTypeNullable,
     sqlTypeIsNullable: sqlTypeNullable,
     alsoAppliesToJsonConversion: appliesToJsonToo,
diff --git a/drift_dev/lib/src/analyzer/helper.dart b/drift_dev/lib/src/analyzer/helper.dart
index 5b563dd7..8a5e343e 100644
--- a/drift_dev/lib/src/analyzer/helper.dart
+++ b/drift_dev/lib/src/analyzer/helper.dart
@@ -26,13 +26,24 @@ class HelperLibrary {
     return type.asInstanceOf(converter);
   }
 
+  /// Converts the given Dart [type] into an instantiation of the
+  /// `TypeConverter` class from drift.
+  ///
+  /// Returns `null` if [type] is not a subtype of `TypeConverter`.
+  InterfaceType? asJsonTypeConverter(DartType type) {
+    final converter = helperLibrary.exportNamespace.get('JsonTypeConverter')
+        as InterfaceElement;
+    return type.asInstanceOf(converter);
+  }
+
   bool isJsonAwareTypeConverter(DartType? type, LibraryElement context) {
     final jsonMixin = helperLibrary.exportNamespace.get('JsonTypeConverter')
         as InterfaceElement;
     final jsonConverterType = jsonMixin.instantiate(
       typeArguments: [
         context.typeProvider.dynamicType,
-        context.typeProvider.dynamicType
+        context.typeProvider.dynamicType,
+        context.typeProvider.dynamicType,
       ],
       nullabilitySuffix: NullabilitySuffix.none,
     );
diff --git a/drift_dev/lib/src/model/types.dart b/drift_dev/lib/src/model/types.dart
index b9672154..03ff81df 100644
--- a/drift_dev/lib/src/model/types.dart
+++ b/drift_dev/lib/src/model/types.dart
@@ -136,6 +136,20 @@ extension OperationOnTypes on HasType {
 
     return variableTypeCode();
   }
+
+  /// The dart type that matches the values of this column. For instance, if a
+  /// table has declared an `IntColumn`, the matching dart type name would be
+  /// [int].
+  String jsonTypeCode() {
+    final converter = typeConverter;
+    if (converter != null) {
+      var inner = converter.jsonType.codeString();
+      if (converter.canBeSkippedForNulls && nullable) inner += '?';
+      return isArray ? 'List<$inner>' : inner;
+    }
+
+    return variableTypeCode();
+  }
 }
 
 const Map<DriftSqlType, String> dartTypeNames = {
diff --git a/drift_dev/lib/src/model/used_type_converter.dart b/drift_dev/lib/src/model/used_type_converter.dart
index ea91a24a..f5525dbb 100644
--- a/drift_dev/lib/src/model/used_type_converter.dart
+++ b/drift_dev/lib/src/model/used_type_converter.dart
@@ -31,6 +31,10 @@ class UsedTypeConverter {
   /// mapped values in the database.
   final DartType sqlType;
 
+  /// The "JSON" type of this type converter. This is the type used to represent
+  /// mapped values in the database.
+  final DartType jsonType;
+
   /// Whether the Dart-value output of this type converter is nullable.
   ///
   /// In other words, [dartType] is potentially nullable.
@@ -80,6 +84,7 @@ class UsedTypeConverter {
     required this.expression,
     required this.dartType,
     required this.sqlType,
+    required this.jsonType,
     required this.dartTypeIsNullable,
     required this.sqlTypeIsNullable,
     this.alsoAppliesToJsonConversion = false,
@@ -115,6 +120,7 @@ class UsedTypeConverter {
       sqlTypeIsNullable: false,
       dartTypeIsNullable: false,
       sqlType: typeProvider.intType,
+      jsonType: typeProvider.intType,
     );
   }
 
@@ -133,11 +139,13 @@ class UsedTypeConverter {
   String converterNameInCode({bool makeNullable = false}) {
     var sqlDartType = sqlType.getDisplayString(withNullability: true);
     if (makeNullable) sqlDartType += '?';
+    var jsonDartType = jsonType.getDisplayString(withNullability: true);
+    if (makeNullable) jsonDartType += '?';
 
-    final className =
-        alsoAppliesToJsonConversion ? 'JsonTypeConverter' : 'TypeConverter';
-
-    return '$className<${dartTypeCode(makeNullable)}, $sqlDartType>';
+    if (alsoAppliesToJsonConversion) {
+      return 'JsonTypeConverter<${dartTypeCode(makeNullable)}, $sqlDartType, $jsonDartType>';
+    }
+    return 'TypeConverter<${dartTypeCode(makeNullable)}, $sqlDartType>';
   }
 }
 
diff --git a/drift_dev/lib/src/writer/tables/data_class_writer.dart b/drift_dev/lib/src/writer/tables/data_class_writer.dart
index b4183229..e511799c 100644
--- a/drift_dev/lib/src/writer/tables/data_class_writer.dart
+++ b/drift_dev/lib/src/writer/tables/data_class_writer.dart
@@ -107,7 +107,7 @@ class DataClassWriter {
 
       final typeConverter = column.typeConverter;
       if (typeConverter != null && typeConverter.alsoAppliesToJsonConversion) {
-        final type = column.innerColumnType(nullable: column.nullable);
+        final type = typeConverter.jsonType;
         final fromConverter = "serializer.fromJson<$type>(json['$jsonKey'])";
         final converterField =
             typeConverter.tableAndField(forNullableColumn: column.nullable);
@@ -151,7 +151,7 @@ class DataClassWriter {
         final converterField =
             typeConverter.tableAndField(forNullableColumn: column.nullable);
         value = '$converterField.toJson($value)';
-        dartType = column.innerColumnType(nullable: true);
+        dartType = column.jsonTypeCode();
       }
 
       _buffer.write("'$name': serializer.toJson<$dartType>($value),");
diff --git a/drift_dev/test/analyzer/dart/type_converter_test.dart b/drift_dev/test/analyzer/dart/type_converter_test.dart
index 297568c5..62fa5e7c 100644
--- a/drift_dev/test/analyzer/dart/type_converter_test.dart
+++ b/drift_dev/test/analyzer/dart/type_converter_test.dart
@@ -15,7 +15,7 @@ void main() {
 import 'package:drift/drift.dart';
 
 TypeConverter<String, String> withoutJson() => throw 'stub';
-JsonTypeConverter<String, String> withJson() => throw 'stub';
+JsonTypeConverter<String, String, String> withJson() => throw 'stub';
 
 class Users extends Table {
   TextColumn get foo => text().map(withoutJson())();

From ff9d419559fccc5c2dfa74a474697be263b51377 Mon Sep 17 00:00:00 2001
From: Alexander Wilde <alexander.wilde87@gmail.com>
Date: Sat, 15 Oct 2022 23:47:58 +0100
Subject: [PATCH 3/6] Backwards compatible attempt

---
 drift/lib/src/drift_dev_helper.dart           |  3 +-
 drift/lib/src/runtime/types/converters.dart   | 46 +++++++++++++++----
 drift/test/generated/todos.dart               |  8 +---
 drift/test/generated/todos.g.dart             |  9 ++--
 drift_dev/lib/src/analyzer/dart_types.dart    |  2 +-
 drift_dev/lib/src/analyzer/helper.dart        | 10 ++--
 .../lib/src/model/used_type_converter.dart    |  2 +-
 .../lib/src/writer/tables/table_writer.dart   |  2 +-
 .../analyzer/dart/type_converter_test.dart    |  2 +-
 9 files changed, 53 insertions(+), 31 deletions(-)

diff --git a/drift/lib/src/drift_dev_helper.dart b/drift/lib/src/drift_dev_helper.dart
index cd21be52..85e31942 100644
--- a/drift/lib/src/drift_dev_helper.dart
+++ b/drift/lib/src/drift_dev_helper.dart
@@ -1,2 +1,3 @@
 // This field is analyzed by drift_dev to easily obtain common types.
-export 'runtime/types/converters.dart' show TypeConverter, JsonTypeConverter;
+export 'runtime/types/converters.dart'
+    show TypeConverter, JsonTypeConverter, JsonTypeConverterWithDifferentTypes;
diff --git a/drift/lib/src/runtime/types/converters.dart b/drift/lib/src/runtime/types/converters.dart
index 4a362bb1..0c140df6 100644
--- a/drift/lib/src/runtime/types/converters.dart
+++ b/drift/lib/src/runtime/types/converters.dart
@@ -33,13 +33,9 @@ abstract class TypeConverter<D, S> {
 /// to SQL (and vice-versa).
 /// When a [BuildGeneralColumn.map] column (or a `MAPPED BY` constraint in
 /// `.drift` files) refers to a type converter that inherits from
-/// [JsonTypeConverter], it will also be used for the conversion from and to
+/// [JsonTypeConverterWithDifferentTypes], it will also be used for the conversion from and to
 /// JSON.
-abstract class JsonTypeConverter<D, S, J> extends TypeConverter<D, S> {
-  /// Empty constant constructor so that subclasses can have a constant
-  /// constructor.
-  const JsonTypeConverter();
-
+mixin JsonTypeConverterWithDifferentTypes<D, S, J> on TypeConverter<D, S> {
   /// Map a value from the Data class to json.
   ///
   /// Defaults to doing the same conversion as for Dart -> SQL, [toSql].
@@ -56,9 +52,39 @@ abstract class JsonTypeConverter<D, S, J> extends TypeConverter<D, S> {
   /// The returned type converter will use the [inner] type converter for non-
   /// null values. Further, `null` is mapped to `null` in both directions (from
   /// Dart to SQL and vice-versa).
-  static JsonTypeConverter<D?, S?, J?>
+  static JsonTypeConverterWithDifferentTypes<D?, S?, J?>
       asNullable<D, S extends Object, J extends Object>(
-          JsonTypeConverter<D, S, J> inner) {
+          JsonTypeConverterWithDifferentTypes<D, S, J> inner) {
+    return _NullWrappingTypeConverterWithJson(inner);
+  }
+}
+
+/// A mixin for [TypeConverter]s that should also apply to drift's builtin
+/// JSON serialization of data classes.
+///
+/// By default, a [TypeConverter] only applies to the serialization from Dart
+/// to SQL (and vice-versa).
+/// When a [BuildGeneralColumn.map] column (or a `MAPPED BY` constraint in
+/// `.drift` files) refers to a type converter that inherits from
+/// [JsonTypeConverter], it will also be used for the conversion from and to
+/// JSON.
+mixin JsonTypeConverter<D, S>
+    implements JsonTypeConverterWithDifferentTypes<D, S, S> {
+  @override
+  S toJson(D value) => toSql(value);
+
+  @override
+  D fromJson(S json) => fromSql(json);
+
+  /// Wraps an [inner] type converter that only considers non-nullable values
+  /// as a type converter that handles null values too.
+  ///
+  /// The returned type converter will use the [inner] type converter for non-
+  /// null values. Further, `null` is mapped to `null` in both directions (from
+  /// Dart to SQL and vice-versa).
+  static JsonTypeConverterWithDifferentTypes<D?, S?, J?>
+      asNullable<D, S extends Object, J extends Object>(
+          JsonTypeConverterWithDifferentTypes<D, S, J> inner) {
     return _NullWrappingTypeConverterWithJson(inner);
   }
 }
@@ -157,8 +183,8 @@ class _NullWrappingTypeConverter<D, S extends Object>
 
 class _NullWrappingTypeConverterWithJson<D, S extends Object, J extends Object>
     extends NullAwareTypeConverter<D, S>
-    implements JsonTypeConverter<D?, S?, J?> {
-  final JsonTypeConverter<D, S, J> _inner;
+    implements JsonTypeConverterWithDifferentTypes<D?, S?, J?> {
+  final JsonTypeConverterWithDifferentTypes<D, S, J> _inner;
 
   const _NullWrappingTypeConverterWithJson(this._inner);
 
diff --git a/drift/test/generated/todos.dart b/drift/test/generated/todos.dart
index dd5fdff5..0168dbf6 100644
--- a/drift/test/generated/todos.dart
+++ b/drift/test/generated/todos.dart
@@ -135,14 +135,8 @@ class CustomConverter extends TypeConverter<MyCustomObject, String> {
 }
 
 class CustomJsonConverter extends CustomConverter
-    implements JsonTypeConverter<MyCustomObject, String, String> {
+    with JsonTypeConverter<MyCustomObject, String> {
   const CustomJsonConverter();
-
-  @override
-  MyCustomObject fromJson(String json) => fromSql(json);
-
-  @override
-  String toJson(MyCustomObject value) => toSql(value);
 }
 
 abstract class CategoryTodoCountView extends View {
diff --git a/drift/test/generated/todos.g.dart b/drift/test/generated/todos.g.dart
index a58388c1..b3c0ee71 100644
--- a/drift/test/generated/todos.g.dart
+++ b/drift/test/generated/todos.g.dart
@@ -1373,10 +1373,11 @@ class $PureDefaultsTable extends PureDefaults
     return $PureDefaultsTable(attachedDatabase, alias);
   }
 
-  static JsonTypeConverter<MyCustomObject, String, String> $converter0 =
-      const CustomJsonConverter();
-  static JsonTypeConverter<MyCustomObject?, String?, String?> $converter0n =
-      JsonTypeConverter.asNullable($converter0);
+  static JsonTypeConverterWithDifferentTypes<MyCustomObject, String, String>
+      $converter0 = const CustomJsonConverter();
+  static JsonTypeConverterWithDifferentTypes<MyCustomObject?, String?, String?>
+      $converter0n =
+      JsonTypeConverterWithDifferentTypes.asNullable($converter0);
 }
 
 class CategoryTodoCountViewData extends DataClass {
diff --git a/drift_dev/lib/src/analyzer/dart_types.dart b/drift_dev/lib/src/analyzer/dart_types.dart
index 1d33cba8..24a0df30 100644
--- a/drift_dev/lib/src/analyzer/dart_types.dart
+++ b/drift_dev/lib/src/analyzer/dart_types.dart
@@ -181,7 +181,7 @@ UsedTypeConverter? readTypeConverter(
           "potentially map to `null` which can't be stored in the database.");
     } else if (!canBeSkippedForNulls) {
       final alternative = appliesToJsonToo
-          ? 'JsonTypeConverter.asNullable'
+          ? 'JsonTypeConverterWithDifferentTypes.asNullable'
           : 'NullAwareTypeConverter.wrap';
 
       reportError('This column is nullable, but the type converter has a non-'
diff --git a/drift_dev/lib/src/analyzer/helper.dart b/drift_dev/lib/src/analyzer/helper.dart
index 8a5e343e..f6053153 100644
--- a/drift_dev/lib/src/analyzer/helper.dart
+++ b/drift_dev/lib/src/analyzer/helper.dart
@@ -27,18 +27,18 @@ class HelperLibrary {
   }
 
   /// Converts the given Dart [type] into an instantiation of the
-  /// `TypeConverter` class from drift.
+  /// `JsonTypeConverter` class from drift.
   ///
   /// Returns `null` if [type] is not a subtype of `TypeConverter`.
   InterfaceType? asJsonTypeConverter(DartType type) {
-    final converter = helperLibrary.exportNamespace.get('JsonTypeConverter')
-        as InterfaceElement;
+    final converter = helperLibrary.exportNamespace
+        .get('JsonTypeConverterWithDifferentTypes') as InterfaceElement;
     return type.asInstanceOf(converter);
   }
 
   bool isJsonAwareTypeConverter(DartType? type, LibraryElement context) {
-    final jsonMixin = helperLibrary.exportNamespace.get('JsonTypeConverter')
-        as InterfaceElement;
+    final jsonMixin = helperLibrary.exportNamespace
+        .get('JsonTypeConverterWithDifferentTypes') as InterfaceElement;
     final jsonConverterType = jsonMixin.instantiate(
       typeArguments: [
         context.typeProvider.dynamicType,
diff --git a/drift_dev/lib/src/model/used_type_converter.dart b/drift_dev/lib/src/model/used_type_converter.dart
index f5525dbb..e4846181 100644
--- a/drift_dev/lib/src/model/used_type_converter.dart
+++ b/drift_dev/lib/src/model/used_type_converter.dart
@@ -143,7 +143,7 @@ class UsedTypeConverter {
     if (makeNullable) jsonDartType += '?';
 
     if (alsoAppliesToJsonConversion) {
-      return 'JsonTypeConverter<${dartTypeCode(makeNullable)}, $sqlDartType, $jsonDartType>';
+      return 'JsonTypeConverterWithDifferentTypes<${dartTypeCode(makeNullable)}, $sqlDartType, $jsonDartType>';
     }
     return 'TypeConverter<${dartTypeCode(makeNullable)}, $sqlDartType>';
   }
diff --git a/drift_dev/lib/src/writer/tables/table_writer.dart b/drift_dev/lib/src/writer/tables/table_writer.dart
index db5550f6..fbaf6993 100644
--- a/drift_dev/lib/src/writer/tables/table_writer.dart
+++ b/drift_dev/lib/src/writer/tables/table_writer.dart
@@ -336,7 +336,7 @@ class TableWriter extends TableOrViewWriter {
             converter.converterNameInCode(makeNullable: true);
 
         final wrap = converter.alsoAppliesToJsonConversion
-            ? 'JsonTypeConverter.asNullable'
+            ? 'JsonTypeConverterWithDifferentTypes.asNullable'
             : 'NullAwareTypeConverter.wrap';
 
         final code = '$wrap(${converter.fieldName})';
diff --git a/drift_dev/test/analyzer/dart/type_converter_test.dart b/drift_dev/test/analyzer/dart/type_converter_test.dart
index 62fa5e7c..297568c5 100644
--- a/drift_dev/test/analyzer/dart/type_converter_test.dart
+++ b/drift_dev/test/analyzer/dart/type_converter_test.dart
@@ -15,7 +15,7 @@ void main() {
 import 'package:drift/drift.dart';
 
 TypeConverter<String, String> withoutJson() => throw 'stub';
-JsonTypeConverter<String, String, String> withJson() => throw 'stub';
+JsonTypeConverter<String, String> withJson() => throw 'stub';
 
 class Users extends Table {
   TextColumn get foo => text().map(withoutJson())();

From 09951adda6c2f88e5e060dab5f092741cd5dd907 Mon Sep 17 00:00:00 2001
From: Alexander Wilde <alexander.wilde87@gmail.com>
Date: Tue, 18 Oct 2022 01:06:22 +0100
Subject: [PATCH 4/6] JsonTypeConverterWithDifferentTypes -> JsonTypeConverter2

---
 drift/lib/src/drift_dev_helper.dart           |  2 +-
 drift/lib/src/runtime/types/converters.dart   | 19 +++++++++----------
 drift/test/generated/todos.g.dart             |  9 ++++-----
 drift_dev/lib/src/analyzer/dart_types.dart    |  2 +-
 drift_dev/lib/src/analyzer/helper.dart        |  8 ++++----
 .../lib/src/model/used_type_converter.dart    |  2 +-
 .../lib/src/writer/tables/table_writer.dart   |  2 +-
 7 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/drift/lib/src/drift_dev_helper.dart b/drift/lib/src/drift_dev_helper.dart
index 85e31942..d667d296 100644
--- a/drift/lib/src/drift_dev_helper.dart
+++ b/drift/lib/src/drift_dev_helper.dart
@@ -1,3 +1,3 @@
 // This field is analyzed by drift_dev to easily obtain common types.
 export 'runtime/types/converters.dart'
-    show TypeConverter, JsonTypeConverter, JsonTypeConverterWithDifferentTypes;
+    show TypeConverter, JsonTypeConverter, JsonTypeConverter2;
diff --git a/drift/lib/src/runtime/types/converters.dart b/drift/lib/src/runtime/types/converters.dart
index 0c140df6..6e0ab070 100644
--- a/drift/lib/src/runtime/types/converters.dart
+++ b/drift/lib/src/runtime/types/converters.dart
@@ -33,9 +33,9 @@ abstract class TypeConverter<D, S> {
 /// to SQL (and vice-versa).
 /// When a [BuildGeneralColumn.map] column (or a `MAPPED BY` constraint in
 /// `.drift` files) refers to a type converter that inherits from
-/// [JsonTypeConverterWithDifferentTypes], it will also be used for the conversion from and to
+/// [JsonTypeConverter2], it will also be used for the conversion from and to
 /// JSON.
-mixin JsonTypeConverterWithDifferentTypes<D, S, J> on TypeConverter<D, S> {
+mixin JsonTypeConverter2<D, S, J> on TypeConverter<D, S> {
   /// Map a value from the Data class to json.
   ///
   /// Defaults to doing the same conversion as for Dart -> SQL, [toSql].
@@ -52,9 +52,9 @@ mixin JsonTypeConverterWithDifferentTypes<D, S, J> on TypeConverter<D, S> {
   /// The returned type converter will use the [inner] type converter for non-
   /// null values. Further, `null` is mapped to `null` in both directions (from
   /// Dart to SQL and vice-versa).
-  static JsonTypeConverterWithDifferentTypes<D?, S?, J?>
+  static JsonTypeConverter2<D?, S?, J?>
       asNullable<D, S extends Object, J extends Object>(
-          JsonTypeConverterWithDifferentTypes<D, S, J> inner) {
+          JsonTypeConverter2<D, S, J> inner) {
     return _NullWrappingTypeConverterWithJson(inner);
   }
 }
@@ -68,8 +68,7 @@ mixin JsonTypeConverterWithDifferentTypes<D, S, J> on TypeConverter<D, S> {
 /// `.drift` files) refers to a type converter that inherits from
 /// [JsonTypeConverter], it will also be used for the conversion from and to
 /// JSON.
-mixin JsonTypeConverter<D, S>
-    implements JsonTypeConverterWithDifferentTypes<D, S, S> {
+mixin JsonTypeConverter<D, S> implements JsonTypeConverter2<D, S, S> {
   @override
   S toJson(D value) => toSql(value);
 
@@ -82,9 +81,9 @@ mixin JsonTypeConverter<D, S>
   /// The returned type converter will use the [inner] type converter for non-
   /// null values. Further, `null` is mapped to `null` in both directions (from
   /// Dart to SQL and vice-versa).
-  static JsonTypeConverterWithDifferentTypes<D?, S?, J?>
+  static JsonTypeConverter2<D?, S?, J?>
       asNullable<D, S extends Object, J extends Object>(
-          JsonTypeConverterWithDifferentTypes<D, S, J> inner) {
+          JsonTypeConverter2<D, S, J> inner) {
     return _NullWrappingTypeConverterWithJson(inner);
   }
 }
@@ -183,8 +182,8 @@ class _NullWrappingTypeConverter<D, S extends Object>
 
 class _NullWrappingTypeConverterWithJson<D, S extends Object, J extends Object>
     extends NullAwareTypeConverter<D, S>
-    implements JsonTypeConverterWithDifferentTypes<D?, S?, J?> {
-  final JsonTypeConverterWithDifferentTypes<D, S, J> _inner;
+    implements JsonTypeConverter2<D?, S?, J?> {
+  final JsonTypeConverter2<D, S, J> _inner;
 
   const _NullWrappingTypeConverterWithJson(this._inner);
 
diff --git a/drift/test/generated/todos.g.dart b/drift/test/generated/todos.g.dart
index b3c0ee71..16c66f2d 100644
--- a/drift/test/generated/todos.g.dart
+++ b/drift/test/generated/todos.g.dart
@@ -1373,11 +1373,10 @@ class $PureDefaultsTable extends PureDefaults
     return $PureDefaultsTable(attachedDatabase, alias);
   }
 
-  static JsonTypeConverterWithDifferentTypes<MyCustomObject, String, String>
-      $converter0 = const CustomJsonConverter();
-  static JsonTypeConverterWithDifferentTypes<MyCustomObject?, String?, String?>
-      $converter0n =
-      JsonTypeConverterWithDifferentTypes.asNullable($converter0);
+  static JsonTypeConverter2<MyCustomObject, String, String> $converter0 =
+      const CustomJsonConverter();
+  static JsonTypeConverter2<MyCustomObject?, String?, String?> $converter0n =
+      JsonTypeConverter2.asNullable($converter0);
 }
 
 class CategoryTodoCountViewData extends DataClass {
diff --git a/drift_dev/lib/src/analyzer/dart_types.dart b/drift_dev/lib/src/analyzer/dart_types.dart
index 24a0df30..bff4315d 100644
--- a/drift_dev/lib/src/analyzer/dart_types.dart
+++ b/drift_dev/lib/src/analyzer/dart_types.dart
@@ -181,7 +181,7 @@ UsedTypeConverter? readTypeConverter(
           "potentially map to `null` which can't be stored in the database.");
     } else if (!canBeSkippedForNulls) {
       final alternative = appliesToJsonToo
-          ? 'JsonTypeConverterWithDifferentTypes.asNullable'
+          ? 'JsonTypeConverter2.asNullable'
           : 'NullAwareTypeConverter.wrap';
 
       reportError('This column is nullable, but the type converter has a non-'
diff --git a/drift_dev/lib/src/analyzer/helper.dart b/drift_dev/lib/src/analyzer/helper.dart
index f6053153..fc956746 100644
--- a/drift_dev/lib/src/analyzer/helper.dart
+++ b/drift_dev/lib/src/analyzer/helper.dart
@@ -31,14 +31,14 @@ class HelperLibrary {
   ///
   /// Returns `null` if [type] is not a subtype of `TypeConverter`.
   InterfaceType? asJsonTypeConverter(DartType type) {
-    final converter = helperLibrary.exportNamespace
-        .get('JsonTypeConverterWithDifferentTypes') as InterfaceElement;
+    final converter = helperLibrary.exportNamespace.get('JsonTypeConverter2')
+        as InterfaceElement;
     return type.asInstanceOf(converter);
   }
 
   bool isJsonAwareTypeConverter(DartType? type, LibraryElement context) {
-    final jsonMixin = helperLibrary.exportNamespace
-        .get('JsonTypeConverterWithDifferentTypes') as InterfaceElement;
+    final jsonMixin = helperLibrary.exportNamespace.get('JsonTypeConverter2')
+        as InterfaceElement;
     final jsonConverterType = jsonMixin.instantiate(
       typeArguments: [
         context.typeProvider.dynamicType,
diff --git a/drift_dev/lib/src/model/used_type_converter.dart b/drift_dev/lib/src/model/used_type_converter.dart
index e4846181..6c1573fb 100644
--- a/drift_dev/lib/src/model/used_type_converter.dart
+++ b/drift_dev/lib/src/model/used_type_converter.dart
@@ -143,7 +143,7 @@ class UsedTypeConverter {
     if (makeNullable) jsonDartType += '?';
 
     if (alsoAppliesToJsonConversion) {
-      return 'JsonTypeConverterWithDifferentTypes<${dartTypeCode(makeNullable)}, $sqlDartType, $jsonDartType>';
+      return 'JsonTypeConverter2<${dartTypeCode(makeNullable)}, $sqlDartType, $jsonDartType>';
     }
     return 'TypeConverter<${dartTypeCode(makeNullable)}, $sqlDartType>';
   }
diff --git a/drift_dev/lib/src/writer/tables/table_writer.dart b/drift_dev/lib/src/writer/tables/table_writer.dart
index fbaf6993..2ad46c58 100644
--- a/drift_dev/lib/src/writer/tables/table_writer.dart
+++ b/drift_dev/lib/src/writer/tables/table_writer.dart
@@ -336,7 +336,7 @@ class TableWriter extends TableOrViewWriter {
             converter.converterNameInCode(makeNullable: true);
 
         final wrap = converter.alsoAppliesToJsonConversion
-            ? 'JsonTypeConverterWithDifferentTypes.asNullable'
+            ? 'JsonTypeConverter2.asNullable'
             : 'NullAwareTypeConverter.wrap';
 
         final code = '$wrap(${converter.fieldName})';

From 92bb5a7fa1adad579075be80ab199935430f5992 Mon Sep 17 00:00:00 2001
From: Simon Binder <oss@simonbinder.eu>
Date: Tue, 18 Oct 2022 20:36:09 +0200
Subject: [PATCH 5/6] Add test and changelog

---
 drift/CHANGELOG.md                          |  5 ++++
 drift/lib/src/runtime/types/converters.dart | 28 ++++++++-------------
 drift/pubspec.yaml                          |  2 +-
 drift/test/generated/todos.dart             | 12 ++++++++-
 drift/test/generated/todos.g.dart           | 14 +++++------
 drift/test/serialization_test.dart          |  8 ++++--
 drift_dev/lib/src/model/types.dart          |  5 ++--
 drift_dev/pubspec.yaml                      |  4 +--
 8 files changed, 44 insertions(+), 34 deletions(-)

diff --git a/drift/CHANGELOG.md b/drift/CHANGELOG.md
index 60d68b5d..66591d38 100644
--- a/drift/CHANGELOG.md
+++ b/drift/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 2.3.0-dev
+
+- Add the `JsonTypeConverter2` mixin. It behaves similar to the existing json
+  type converters, but can use a different SQL and JSON type.
+
 ## 2.2.0
 
 - Always escape column names, avoiding the costs of using a regular expression
diff --git a/drift/lib/src/runtime/types/converters.dart b/drift/lib/src/runtime/types/converters.dart
index 6e0ab070..a6b3011b 100644
--- a/drift/lib/src/runtime/types/converters.dart
+++ b/drift/lib/src/runtime/types/converters.dart
@@ -29,12 +29,11 @@ abstract class TypeConverter<D, S> {
 /// A mixin for [TypeConverter]s that should also apply to drift's builtin
 /// JSON serialization of data classes.
 ///
-/// By default, a [TypeConverter] only applies to the serialization from Dart
-/// to SQL (and vice-versa).
-/// When a [BuildGeneralColumn.map] column (or a `MAPPED BY` constraint in
-/// `.drift` files) refers to a type converter that inherits from
-/// [JsonTypeConverter2], it will also be used for the conversion from and to
-/// JSON.
+/// Unlike the old [JsonTypeConverter] mixin, this more general mixin allows
+/// using a different type when serializing to JSON ([J]) than the type used in
+/// SQL ([S]).
+/// For the cases where the JSON serialization and the mapping to SQL use the
+/// same types, it may be more convenient to mix-in [JsonTypeConverter] instead.
 mixin JsonTypeConverter2<D, S, J> on TypeConverter<D, S> {
   /// Map a value from the Data class to json.
   ///
@@ -68,24 +67,17 @@ mixin JsonTypeConverter2<D, S, J> on TypeConverter<D, S> {
 /// `.drift` files) refers to a type converter that inherits from
 /// [JsonTypeConverter], it will also be used for the conversion from and to
 /// JSON.
+///
+/// If the serialized JSON has a different type than the type in SQL ([S]), use
+/// a [JsonTypeConverter2]. For instance, this could be useful if your type
+/// converter between Dart and SQL maps to a string in SQL, but to a `Map` in
+/// JSON.
 mixin JsonTypeConverter<D, S> implements JsonTypeConverter2<D, S, S> {
   @override
   S toJson(D value) => toSql(value);
 
   @override
   D fromJson(S json) => fromSql(json);
-
-  /// Wraps an [inner] type converter that only considers non-nullable values
-  /// as a type converter that handles null values too.
-  ///
-  /// The returned type converter will use the [inner] type converter for non-
-  /// null values. Further, `null` is mapped to `null` in both directions (from
-  /// Dart to SQL and vice-versa).
-  static JsonTypeConverter2<D?, S?, J?>
-      asNullable<D, S extends Object, J extends Object>(
-          JsonTypeConverter2<D, S, J> inner) {
-    return _NullWrappingTypeConverterWithJson(inner);
-  }
 }
 
 /// Implementation for an enum to int converter that uses the index of the enum
diff --git a/drift/pubspec.yaml b/drift/pubspec.yaml
index 4f2df168..a96cc96f 100644
--- a/drift/pubspec.yaml
+++ b/drift/pubspec.yaml
@@ -1,6 +1,6 @@
 name: drift
 description: Drift is a reactive library to store relational data in Dart and Flutter applications.
-version: 2.2.0
+version: 2.3.0-dev
 repository: https://github.com/simolus3/drift
 homepage: https://drift.simonbinder.eu/
 issue_tracker: https://github.com/simolus3/drift/issues
diff --git a/drift/test/generated/todos.dart b/drift/test/generated/todos.dart
index 0168dbf6..02d46fc7 100644
--- a/drift/test/generated/todos.dart
+++ b/drift/test/generated/todos.dart
@@ -135,8 +135,18 @@ class CustomConverter extends TypeConverter<MyCustomObject, String> {
 }
 
 class CustomJsonConverter extends CustomConverter
-    with JsonTypeConverter<MyCustomObject, String> {
+    with JsonTypeConverter2<MyCustomObject, String, Map> {
   const CustomJsonConverter();
+
+  @override
+  MyCustomObject fromJson(Map json) {
+    return MyCustomObject(json['data'] as String);
+  }
+
+  @override
+  Map toJson(MyCustomObject value) {
+    return {'data': value.data};
+  }
 }
 
 abstract class CategoryTodoCountView extends View {
diff --git a/drift/test/generated/todos.g.dart b/drift/test/generated/todos.g.dart
index 16c66f2d..c5bf0896 100644
--- a/drift/test/generated/todos.g.dart
+++ b/drift/test/generated/todos.g.dart
@@ -1252,7 +1252,7 @@ class PureDefault extends DataClass implements Insertable<PureDefault> {
     serializer ??= driftRuntimeOptions.defaultSerializer;
     return PureDefault(
       txt: $PureDefaultsTable.$converter0n
-          .fromJson(serializer.fromJson<String>(json['txt'])),
+          .fromJson(serializer.fromJson<Map<dynamic, dynamic>>(json['txt'])),
     );
   }
   factory PureDefault.fromJsonString(String encodedJson,
@@ -1264,8 +1264,8 @@ class PureDefault extends DataClass implements Insertable<PureDefault> {
   Map<String, dynamic> toJson({ValueSerializer? serializer}) {
     serializer ??= driftRuntimeOptions.defaultSerializer;
     return <String, dynamic>{
-      'txt': serializer
-          .toJson<String?>($PureDefaultsTable.$converter0n.toJson(txt)),
+      'txt': serializer.toJson<Map<dynamic, dynamic>?>(
+          $PureDefaultsTable.$converter0n.toJson(txt)),
     };
   }
 
@@ -1373,10 +1373,10 @@ class $PureDefaultsTable extends PureDefaults
     return $PureDefaultsTable(attachedDatabase, alias);
   }
 
-  static JsonTypeConverter2<MyCustomObject, String, String> $converter0 =
-      const CustomJsonConverter();
-  static JsonTypeConverter2<MyCustomObject?, String?, String?> $converter0n =
-      JsonTypeConverter2.asNullable($converter0);
+  static JsonTypeConverter2<MyCustomObject, String, Map<dynamic, dynamic>>
+      $converter0 = const CustomJsonConverter();
+  static JsonTypeConverter2<MyCustomObject?, String?, Map<dynamic, dynamic>?>
+      $converter0n = JsonTypeConverter2.asNullable($converter0);
 }
 
 class CategoryTodoCountViewData extends DataClass {
diff --git a/drift/test/serialization_test.dart b/drift/test/serialization_test.dart
index c04b00b9..f3b8f18d 100644
--- a/drift/test/serialization_test.dart
+++ b/drift/test/serialization_test.dart
@@ -82,8 +82,12 @@ void main() {
     });
 
     test('applies json type converter', () {
-      expect(PureDefault(txt: MyCustomObject('foo')).toJson(), {'txt': 'foo'});
-      expect(PureDefault.fromJson({'txt': 'foo'}),
+      const serialized = {
+        'txt': {'data': 'foo'}
+      };
+
+      expect(PureDefault(txt: MyCustomObject('foo')).toJson(), serialized);
+      expect(PureDefault.fromJson(serialized),
           PureDefault(txt: MyCustomObject('foo')));
     });
 
diff --git a/drift_dev/lib/src/model/types.dart b/drift_dev/lib/src/model/types.dart
index 03ff81df..097ed43d 100644
--- a/drift_dev/lib/src/model/types.dart
+++ b/drift_dev/lib/src/model/types.dart
@@ -137,9 +137,8 @@ extension OperationOnTypes on HasType {
     return variableTypeCode();
   }
 
-  /// The dart type that matches the values of this column. For instance, if a
-  /// table has declared an `IntColumn`, the matching dart type name would be
-  /// [int].
+  /// The Dart type that matches the values of this column when serialized to
+  /// JSON.
   String jsonTypeCode() {
     final converter = typeConverter;
     if (converter != null) {
diff --git a/drift_dev/pubspec.yaml b/drift_dev/pubspec.yaml
index 1d7d7b91..7d10c1dc 100644
--- a/drift_dev/pubspec.yaml
+++ b/drift_dev/pubspec.yaml
@@ -1,6 +1,6 @@
 name: drift_dev
 description: Dev-dependency for users of drift. Contains a the generator and development tools.
-version: 2.2.0+1
+version: 2.3.0-dev
 repository: https://github.com/simolus3/drift
 homepage: https://drift.simonbinder.eu/
 issue_tracker: https://github.com/simolus3/drift/issues
@@ -25,7 +25,7 @@ dependencies:
   io: ^1.0.3
 
   # Drift-specific analysis and apis
-  drift: '>=2.0.0 <2.3.0'
+  drift: '>=2.3.0 <2.4.0'
   sqlite3: '>=0.1.6 <2.0.0'
   sqlparser: ^0.23.3
 

From 51f4c282832980f740677ebc014108ff20af3ba6 Mon Sep 17 00:00:00 2001
From: Simon Binder <oss@simonbinder.eu>
Date: Tue, 18 Oct 2022 20:39:50 +0200
Subject: [PATCH 6/6] Document new type converters

---
 docs/pages/docs/Advanced Features/type_converters.md | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/docs/pages/docs/Advanced Features/type_converters.md b/docs/pages/docs/Advanced Features/type_converters.md
index 08eca372..ba71d93f 100644
--- a/docs/pages/docs/Advanced Features/type_converters.md	
+++ b/docs/pages/docs/Advanced Features/type_converters.md	
@@ -123,6 +123,13 @@ If you want to apply the same conversion to JSON as well, make your type convert
 You can also override the `toJson` and `fromJson` methods to customize serialization as long as the types
 stay the compatible.
 
-If you want to serialize to a different JSON type (e.g. you have a type converter `<MyObject, int>` in SQL but
-want to map to a string in JSON), you'll have to write a custom [`ValueSerializer`](https://drift.simonbinder.eu/api/drift/valueserializer-class)
+If the JSON type you want to serialize to is different to the SQL type you're
+mapping to, you can mix-in `JsonTypeConverter2` instead.
+For instance, say you have a type converter mapping to a complex Dart type
+`MyObject`. In SQL, you might want to store this as an `String`. But when
+serializing to JSON, you may want to use a `Map<String, Object?>`. Here, simply
+add the `JsonTypeConverter2<MyObject, String, Map<String, Object?>>` mixin to
+your type converter.
+
+As an alternative to using JSON type converters, you can use a custom [`ValueSerializer`](https://drift.simonbinder.eu/api/drift/valueserializer-class)
 and pass it to the serialization methods.