[pigeon] fixed null support for java enums (#528)

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.12
+
+* [java] Fixes enum support for null values.
+
 ## 1.0.11
 
 * [ci] Starts transition to a Dart test runner, adds windows support.

packages/pigeon/lib/generator_tools.dart

@@ -8,7 +8,7 @@ import 'dart:mirrors';
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '1.0.11';
+const String pigeonVersion = '1.0.12';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/java_generator.dart

@@ -474,13 +474,13 @@ void generateJava(JavaOptions options, Root root, StringSink sink) {
                 root.enums,
                 (NamedType x) => _javaTypeForBuiltinDartType(x.type));
             String toWriteValue = '';
+            final String fieldName = field.name;
             if (!hostDatatype.isBuiltin &&
                 rootClassNameSet.contains(field.type.baseName)) {
-              final String fieldName = field.name;
               toWriteValue = '($fieldName == null) ? null : $fieldName.toMap()';
             } else if (!hostDatatype.isBuiltin &&
                 rootEnumNameSet.contains(field.type.baseName)) {
-              toWriteValue = '${field.name}.index';
+              toWriteValue = '$fieldName == null ? null : $fieldName.index';
             } else {
               toWriteValue = field.name;
             }
@@ -492,13 +492,14 @@ void generateJava(JavaOptions options, Root root, StringSink sink) {
         indent.scoped('{', '}', () {
           indent.writeln('${klass.name} fromMapResult = new ${klass.name}();');
           for (final NamedType field in klass.fields) {
-            indent.writeln('Object ${field.name} = map.get("${field.name}");');
+            final String fieldVariable = field.name;
+            indent.writeln('Object $fieldVariable = map.get("${field.name}");');
             if (rootEnumNameSet.contains(field.type.baseName)) {
               indent.writeln(
-                  'fromMapResult.${field.name} = ${field.type.baseName}.values()[(int)${field.name}];');
+                  'fromMapResult.${field.name} = $fieldVariable == null ? null : ${field.type.baseName}.values()[(int)$fieldVariable];');
             } else {
               indent.writeln(
-                  'fromMapResult.${field.name} = ${_castObject(field, root.classes, root.enums, field.name)};');
+                  'fromMapResult.${field.name} = ${_castObject(field, root.classes, root.enums, fieldVariable)};');
             }
           }
           indent.writeln('return fromMapResult;');

packages/pigeon/platform_tests/android_unit_tests/android/app/src/test/java/com/example/android_unit_tests/EnumTest.java

@@ -0,0 +1,21 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package com.example.android_unit_tests;
+
+import static org.junit.Assert.*;
+
+import java.util.Map;
+import org.junit.Test;
+
+public class EnumTest {
+  @Test
+  public void nullValue() {
+    Enum.Data value = new Enum.Data();
+    value.setState(null);
+    Map<String, Object> map = value.toMap();
+    Enum.Data readValue = Enum.Data.fromMap(map);
+    assertEquals(value.getState(), readValue.getState());
+  }
+}

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/master/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 1.0.11 # This must match the version in lib/generator_tools.dart
+version: 1.0.12 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: '>=2.12.0 <3.0.0'

packages/pigeon/run_tests.sh

@@ -320,6 +320,7 @@ run_android_unittests() {
   gen_android_unittests_code ./pigeons/all_void.dart AllVoid
   gen_android_unittests_code ./pigeons/android_unittests.dart Pigeon
   gen_android_unittests_code ./pigeons/async_handlers.dart AsyncHandlers
+  gen_android_unittests_code ./pigeons/enum.dart Enum
   gen_android_unittests_code ./pigeons/host2flutter.dart Host2Flutter
   gen_android_unittests_code ./pigeons/java_double_host_api.dart JavaDoubleHostApi
   gen_android_unittests_code ./pigeons/list.dart PigeonList

packages/pigeon/test/java_generator_test.dart

@@ -609,8 +609,14 @@ void main() {
     expect(code, contains('private Enum1(final int index) {'));
     expect(code, contains('      this.index = index;'));
 
-    expect(code, contains('toMapResult.put("enum1", enum1.index);'));
-    expect(code, contains('fromMapResult.enum1 = Enum1.values()[(int)enum1];'));
+    expect(
+        code,
+        contains(
+            'toMapResult.put("enum1", enum1 == null ? null : enum1.index);'));
+    expect(
+        code,
+        contains(
+            'fromMapResult.enum1 = enum1 == null ? null : Enum1.values()[(int)enum1];'));
   });
 
   Iterable<String> _makeIterable(String string) sync* {