[Pigeon] Added comment to opt out of nnbd for now

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.1.7
+
+* Fixed Dart compilation for later versions that support null safety, opting out
+  of it for now.
+
 ## 0.1.6
 
 * Fixed unused variable linter warning in Dart code under certain conditions.

packages/pigeon/lib/dart_generator.dart

@@ -138,6 +138,7 @@ void generateDart(Root root, StringSink sink) {
   indent.writeln(
       'import \'dart:typed_data\' show Uint8List, Int32List, Int64List, Float64List;');
   indent.writeln('');
+  indent.writeln('// @dart = 2.8');
 
   for (Class klass in root.classes) {
     sink.write('class ${klass.name} ');

packages/pigeon/lib/generator_tools.dart

@@ -8,7 +8,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon.
-const String pigeonVersion = '0.1.6';
+const String pigeonVersion = '0.1.7';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/pubspec.yaml

@@ -1,5 +1,5 @@
 name: pigeon
-version: 0.1.6
+version: 0.1.7
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 homepage: https://github.com/flutter/packages/tree/master/packages/pigeon
 dependencies:

packages/pigeon/test/dart_generator_test.dart

@@ -180,4 +180,21 @@ void main() {
     expect(code, matches('\'${Keys.result}\': output._toMap()'));
     expect(code, contains('return <dynamic, dynamic>{};'));
   });
+
+  test('opt out of nndb', () {
+    final Class klass = Class()
+      ..name = 'Foobar'
+      ..fields = <Field>[
+        Field()
+          ..name = 'field1'
+          ..dataType = 'dataType1'
+      ];
+    final Root root = Root()
+      ..apis = <Api>[]
+      ..classes = <Class>[klass];
+    final StringBuffer sink = StringBuffer();
+    generateDart(root, sink);
+    final String code = sink.toString();
+    expect(code, contains('// @dart = 2.8'));
+  });
 }