Avoid allowCustom argument

packages/CHANGELOG.ejson.md

@@ -2,9 +2,6 @@
 
 - `fromEJson<T>` now accepts a `defaultValue` argument that is returned if  
   `null` is passed as `ejson`.
-- `fromEJson<T>` now accepts a `allowCustom` argument that can be used to specify
-  the custom decoders are allowed to be used. Defaults to `null`, which specify that
-  currently set value on the stack should be used. At top level the default is `true`.
 - `register<T>` takes an optional `superTypes` argument to specify the super 
   types of `T` if needed.
 

packages/ejson/lib/src/decoding.dart

@@ -65,25 +65,19 @@ final _decoders = CombinedMapView([customDecoders, commonDecoders]);
 ///
 /// Throws [InvalidEJson] if [ejson] is not valid for [T].
 /// Throws [MissingDecoder] if no decoder is registered for [T].
-T fromEJson<T>(EJsonValue ejson, {bool? allowCustom, T? defaultValue}) {
-  final oldAllowCustom = _allowCustom;
-  _allowCustom = allowCustom ?? _allowCustom;
-  try {
-    final type = T;
-    final nullable = type.isNullable;
-    if (!nullable && ejson == null && defaultValue != null) return defaultValue;
-    final decoder = nullable ? _decodeNullable : _decoders[type.base];
-    if (decoder == null) {
-      throw MissingDecoder._(ejson, type);
-    }
-    final args = nullable ? [type.nonNull] : type.args;
-    if (args.isEmpty) {
-      return decoder(ejson) as T; // minor optimization
-    }
-    return decoder.callWith(typeArguments: args, parameters: [ejson]) as T;
-  } finally {
-    _allowCustom = oldAllowCustom;
+T fromEJson<T>(EJsonValue ejson, {T? defaultValue}) {
+  final type = T;
+  final nullable = type.isNullable;
+  if (ejson == null && defaultValue != null) return defaultValue;
+  final decoder = nullable ? _decodeNullable : _decoders[type.base];
+  if (decoder == null) {
+    throw MissingDecoder._(ejson, type);
   }
+  final args = nullable ? [type.nonNull] : type.args;
+  if (args.isEmpty) {
+    return decoder(ejson) as T; // minor optimization
+  }
+  return decoder.callWith(typeArguments: args, parameters: [ejson]) as T;
 }
 
 /// Parses [source] to [EJsonValue] and convert to type [T].
@@ -116,37 +110,23 @@ dynamic _decodeAny(EJsonValue ejson) {
     {'\$oid': _} => _decodeObjectId(ejson),
     {'\$binary': {'base64': _, 'subType': '04'}} => _decodeUuid(ejson),
     {'\$binary': _} => _decodeBinary(ejson),
-    List<dynamic> _ => _decodeArray<dynamic>(ejson),
-    Set<dynamic> _ => _decodeSet<dynamic>(ejson),
-    Map<dynamic, dynamic> _ => _tryDecodeCustomIfAllowed(ejson) ?? _decodeDocument<String, dynamic>(ejson), // other maps goes last!!
+    List _ => _decodeArray<dynamic>(ejson),
+    Set _ => _decodeSet<dynamic>(ejson),
+    Map _ => _decodeDocument<String, dynamic>(ejson), // other maps goes last!!
     _ => raiseInvalidEJson<dynamic>(ejson),
   };
 }
 
-bool _allowCustom = true;
-dynamic _tryDecodeCustomIfAllowed(EJsonValue ejson) {
-  if (_allowCustom) {
-    for (final decoder in customDecoders.values) {
-      try {
-        return decoder(ejson);
-      } catch (_) {
-        // ignore
-      }
-    }
-  }
-  return null;
-}
-
 List<T> _decodeArray<T>(EJsonValue ejson) {
   return switch (ejson) {
-    Iterable<dynamic> i => i.map((ejson) => fromEJson<T>(ejson)).toList(),
+    Iterable i => i.map((ejson) => fromEJson<T>(ejson)).toList(),
     _ => raiseInvalidEJson(ejson),
   };
 }
 
 Set<T> _decodeSet<T>(EJsonValue ejson) {
   return switch (ejson) {
-    Iterable<dynamic> i => i.map((ejson) => fromEJson<T>(ejson)).toSet(),
+    Iterable i => i.map((ejson) => fromEJson<T>(ejson)).toSet(),
     _ => raiseInvalidEJson(ejson),
   };
 }
@@ -167,20 +147,23 @@ DateTime _decodeDate(EJsonValue ejson) {
 }
 
 DBRef<KeyT> _decodeDBRef<KeyT>(EJsonValue ejson) {
-  return switch (ejson) {
-    {'\$ref': String collection, '\$id': EJsonValue id} => DBRef<KeyT>(collection, fromEJson<KeyT>(id)),
-    _ => raiseInvalidEJson(ejson),
-  };
+  switch (ejson) {
+    case {'\$ref': String collection, '\$id': EJsonValue id}:
+      KeyT key = fromEJson(id);
+      return DBRef.new.callWith(parameters: [collection, key], typeArguments: [key.runtimeType]) as DBRef<KeyT>;
+    default:
+      return raiseInvalidEJson(ejson);
+  }
 }
 
 Defined<T> _decodeDefined<T>(EJsonValue ejson) {
   if (ejson case {'\$undefined': 1}) return raiseInvalidEJson(ejson);
-  return Defined<T>(fromEJson<T>(ejson));
+  return Defined(fromEJson(ejson));
 }
 
 Map<K, V> _decodeDocument<K, V>(EJsonValue ejson) {
   return switch (ejson) {
-    Map<dynamic, dynamic> m => m.map((key, value) => MapEntry(key as K, fromEJson<V>(value))),
+    Map m => m.map((key, value) => MapEntry(key as K, fromEJson(value))),
     _ => raiseInvalidEJson(ejson),
   };
 }
@@ -263,14 +246,14 @@ Symbol _decodeSymbol(EJsonValue ejson) {
 
 Undefined<T> _decodeUndefined<T>(EJsonValue ejson) {
   return switch (ejson) {
-    {'\$undefined': 1} => Undefined<T>(),
+    {'\$undefined': 1} => Undefined(),
     _ => raiseInvalidEJson(ejson),
   };
 }
 
 UndefinedOr<T> _decodeUndefinedOr<T>(EJsonValue ejson) {
   return switch (ejson) {
-    {'\$undefined': 1} => Undefined<T>(),
+    {'\$undefined': 1} => Undefined(),
     _ => _decodeDefined(ejson),
   };
 }

packages/ejson/lib/src/types.dart

@@ -31,6 +31,8 @@ enum EJsonType {
 /// and [MinKey](https://www.mongodb.com/docs/manual/reference/mongodb-extended-json/#mongodb-bsontype-MinKey)
 enum BsonKey { min, max }
 
+/// See [DBRef](https://github.com/mongodb/specifications/blob/master/source/dbref.md)
+/// This is not technically a BSON type, but a common convention. 
 final class DBRef<KeyT> {
   // Do we need to support the database name?
   final String collection;

packages/ejson/test/ejson_test.dart

@@ -10,9 +10,41 @@ import 'package:ejson/ejson.dart';
 import 'package:objectid/objectid.dart';
 import 'package:sane_uuid/uuid.dart';
 import 'package:test/test.dart';
+import 'package:type_plus/type_plus.dart';
 
 import 'person.dart';
 
+bool _canDecodeAny<T>([Type? type]) {
+  commonDecoders; // ensure common types has been registered;
+  type ??= T;
+  if (type.isNullable) return _canDecodeAny(type.base);
+  if ([
+    dynamic,
+    Null,
+    Object,
+    bool,
+    double,
+    int,
+    num,
+    String,
+    DateTime,
+    BsonKey,
+    Symbol,
+    ObjectId,
+    Uuid,
+    Uint8List,
+  ].contains(type)) return true;
+  if ([
+    List,
+    Set,
+    Map,
+    DBRef,
+    Undefined,
+    UndefinedOr,
+  ].contains(type.base)) return type.args.every(_canDecodeAny);
+  return false;
+}
+
 void _testCase<T>(T value, EJsonValue expected) {
   test('encode from $value of type $T', () {
     expect(toEJson(value), expected);
@@ -46,7 +78,7 @@ void _testCase<T>(T value, EJsonValue expected) {
     expect(() => fromEJson(expected), returnsNormally);
   });
 
-  if (value is! Defined && value is! DBRef) {
+  if (_canDecodeAny<T>()) {
     test('roundtrip $value of type $T as dynamic', () {
       // no <T> here, so dynamic
       expect(fromEJson(toEJson(value)), value);

packages/ejson_generator/test/ctor_test.dart

@@ -85,13 +85,6 @@ void _testCase<T>(T value, EJsonValue expected) {
   test('roundtrip $expected as $T', () {
     expect(toEJson(fromEJson<T>(expected)), expected);
   });
-
-  test('roundtrip $expected of type $T as dynamic', () {
-    // no <T> here, so dynamic
-    final decoded = fromEJson<dynamic>(expected);
-    expect(decoded, isA<T>());
-    expect(toEJson(decoded), expected);
-  });
 }
 
 void main() {

packages/realm_dart/lib/src/handles/native/init.dart

@@ -158,7 +158,7 @@ EJsonValue encodeRealmValue(RealmValue value) {
 }
 
 RealmValue decodeRealmValue(EJsonValue ejson) {
-  Object? decoded = fromEJson(ejson, allowCustom: false);
+  final decoded = fromEJson<dynamic>(ejson);
   if (decoded is DBRef) {
     final t = TypePlus.fromId(decoded.collection);
     final o = RealmObjectBase.createObject(t, null);