Correctly parse lists of enums in Dart generated code (#7157)

* Correctly parse lists of enums in Dart generated code

* Add a test for #6869

* Commit generated code

* Fixed missing newline-at-eof

dart/test/flat_buffers_test.dart

@@ -13,6 +13,7 @@ import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import './monster_test_my_game.example_generated.dart' as example;
 import './monster_test_my_game.example2_generated.dart' as example2;
+import './list_of_enums_generated.dart' as example3;
 
 main() {
   defineReflectiveSuite(() {
@@ -20,6 +21,7 @@ main() {
     defineReflectiveTests(ObjectAPITest);
     defineReflectiveTests(CheckOtherLangaugesData);
     defineReflectiveTests(GeneratorTest);
+    defineReflectiveTests(ListOfEnumsTest);
   });
 }
 
@@ -902,3 +904,17 @@ class GeneratorTest {
         same(example.AnyAmbiguousAliasesTypeId.values));
   }
 }
+
+// See #6869
+@reflectiveTest
+class ListOfEnumsTest {
+  void test_listOfEnums() async {
+    var mytable = example3.MyTableObjectBuilder(
+      options: [example3.OptionsEnum.A, example3.OptionsEnum.B, example3.OptionsEnum.C]);
+    var bytes = mytable.toBytes();
+    var mytable_read = example3.MyTable(bytes);
+    expect(mytable_read.options![0].value, example3.OptionsEnum.A.value);
+    expect(mytable_read.options![1].value, example3.OptionsEnum.B.value);
+    expect(mytable_read.options![2].value, example3.OptionsEnum.C.value);
+  }
+}

dart/test/list_of_enums.fbs

@@ -0,0 +1,10 @@
+enum OptionsEnum : uint32
+{
+    A = 1,
+    B = 2,
+    C = 3
+}
+
+table MyTable {
+    options : [OptionsEnum];
+}

src/idl_gen_dart.cpp

@@ -308,7 +308,7 @@ class DartGenerator : public BaseGenerator {
             "> {\n";
     code += "  const _" + name + "Reader();\n\n";
     code += "  @override\n";
-    code += "  int get size => 1;\n\n";
+    code += "  int get size => " + EnumSize(enum_def.underlying_type) + ";\n\n";
     code += "  @override\n";
     code +=
         "  " + name + " read(" + _kFb + ".BufferContext bc, int offset) =>\n";
@@ -339,6 +339,24 @@ class DartGenerator : public BaseGenerator {
     }
   }
 
+  static std::string EnumSize(const Type &type) {
+    switch (type.base_type) {
+      case BASE_TYPE_BOOL:
+      case BASE_TYPE_CHAR:
+      case BASE_TYPE_UTYPE:
+      case BASE_TYPE_UCHAR: return "1";
+      case BASE_TYPE_SHORT:
+      case BASE_TYPE_USHORT: return "2";
+      case BASE_TYPE_INT:
+      case BASE_TYPE_UINT:
+      case BASE_TYPE_FLOAT: return "4";
+      case BASE_TYPE_LONG:
+      case BASE_TYPE_ULONG:
+      case BASE_TYPE_DOUBLE: return "8";
+      default: return "1";
+    }
+  }
+
   std::string GenReaderTypeName(const Type &type, Namespace *current_namespace,
                                 const FieldDef &def,
                                 bool parent_is_vector = false, bool lazy = true,

tests/DartTest.sh

@@ -25,6 +25,8 @@ cp monster_test.fbs ../dart/test
 
 cd ../dart
 
+../flatc --dart --gen-object-api -o ./test ./test/list_of_enums.fbs
+
 # update packages
 dart pub get
 # Execute the sample.

tests/monster_test_my_game.example_generated.dart

@@ -152,7 +152,7 @@ class _LongEnumReader extends fb.Reader<LongEnum> {
   const _LongEnumReader();
 
   @override
-  int get size => 1;
+  int get size => 8;
 
   @override
   LongEnum read(fb.BufferContext bc, int offset) =>