[pigeon] Standardize host api error handling

packages/pigeon/CHANGELOG.md

@@ -1,10 +1,19 @@
+## 9.0.2
+
+* [java] Adds a `GeneratedApi.FlutterError` exception for passing custom error parameters (code, message, details).
+* [kotlin] Adds a `FlutterError` exception for passing custom error parameters (code, message, details).
+* [kotlin] Adds a `errorClassName` option in `KotlinOptions` for custom error class names.
+* [java] Removes legacy try catch in async apis.
+* Adds `FlutterError` handling integration tests for all platforms.
+
 ## 9.0.1
 
 * Updates links for the merge of flutter/plugins into flutter/packages.
 
 ## 9.0.0
 
-* **Breaking Change** Updates `DartOptions` to be immutable and adds const to the constructor.
+* **Breaking Change** Updates `DartOptions` to be immutable and 
+adds const to the constructor.
 * [java] Reverts `final` changes to Flutter Api classes.
 
 ## 8.0.0

packages/pigeon/lib/generator_tools.dart

@@ -11,7 +11,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '9.0.1';
+const String pigeonVersion = '9.0.2';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/java_generator.dart

@@ -606,46 +606,50 @@ class JavaGenerator extends StructuredGenerator<JavaOptions> {
                 : _javaTypeForDartType(method.returnType);
             indent.writeln(
                 'ArrayList<Object> wrapped = new ArrayList<Object>();');
-            indent.write('try ');
-            indent.addScoped('{', '}', () {
-              final List<String> methodArgument = <String>[];
-              if (method.arguments.isNotEmpty) {
+            final List<String> methodArgument = <String>[];
+            if (method.arguments.isNotEmpty) {
+              indent.writeln(
+                  'ArrayList<Object> args = (ArrayList<Object>) message;');
+              indent.write('if (args == null) ');
+              indent.addScoped('{', '}', () {
                 indent.writeln(
-                    'ArrayList<Object> args = (ArrayList<Object>) message;');
-                indent.writeln('assert args != null;');
-                enumerate(method.arguments, (int index, NamedType arg) {
-                  // The StandardMessageCodec can give us [Integer, Long] for
-                  // a Dart 'int'.  To keep things simple we just use 64bit
-                  // longs in Pigeon with Java.
-                  final bool isInt = arg.type.baseName == 'int';
-                  final String argType =
-                      isInt ? 'Number' : _javaTypeForDartType(arg.type);
-                  final String argName = _getSafeArgumentName(index, arg);
-                  final String argExpression = isInt
-                      ? '($argName == null) ? null : $argName.longValue()'
-                      : argName;
-                  String accessor = 'args.get($index)';
-                  if (isEnum(root, arg.type)) {
-                    accessor = _intToEnum(accessor, arg.type.baseName);
-                  } else if (argType != 'Object') {
-                    accessor = '($argType) $accessor';
-                  }
-                  indent.writeln('$argType $argName = $accessor;');
-                  if (!arg.type.isNullable) {
-                    indent.write('if ($argName == null) ');
-                    indent.addScoped('{', '}', () {
-                      indent.writeln(
-                          'throw new NullPointerException("$argName unexpectedly null.");');
-                    });
-                  }
-                  methodArgument.add(argExpression);
-                });
-              }
-              if (method.isAsynchronous) {
-                final String resultValue =
-                    method.returnType.isVoid ? 'null' : 'result';
-                const String resultName = 'resultCallback';
-                indent.format('''
+                    'reply.reply(wrapError(new IllegalArgumentException("Arguments expected but none received.")));');
+                indent.writeln('return;');
+              });
+              enumerate(method.arguments, (int index, NamedType arg) {
+                // The StandardMessageCodec can give us [Integer, Long] for
+                // a Dart 'int'.  To keep things simple we just use 64bit
+                // longs in Pigeon with Java.
+                final bool isInt = arg.type.baseName == 'int';
+                final String argType =
+                    isInt ? 'Number' : _javaTypeForDartType(arg.type);
+                final String argName = _getSafeArgumentName(index, arg);
+                final String argExpression = isInt
+                    ? '($argName == null) ? null : $argName.longValue()'
+                    : argName;
+                String accessor = 'args.get($index)';
+                if (isEnum(root, arg.type)) {
+                  accessor = _intToEnum(accessor, arg.type.baseName);
+                } else if (argType != 'Object') {
+                  accessor = '($argType) $accessor';
+                }
+                indent.writeln('$argType $argName = $accessor;');
+                if (!arg.type.isNullable) {
+                  indent.write('if ($argName == null) ');
+                  indent.addScoped('{', '}', () {
+                    indent.writeln(
+                        'reply.reply(wrapError(new NullPointerException("aStringArg unexpectedly null.")));');
+                    indent.writeln('return;');
+                  });
+                }
+                methodArgument.add(argExpression);
+              });
+            }
+            if (method.isAsynchronous) {
+              final String resultValue =
+                  method.returnType.isVoid ? 'null' : 'result';
+              const String resultName = 'resultCallback';
+              indent.format('''
 Result<$returnType> $resultName = 
 \t\tnew Result<$returnType>() {
 \t\t\tpublic void success($returnType result) {
@@ -659,31 +663,33 @@ Result<$returnType> $resultName =
 \t\t\t}
 \t\t};
 ''');
-                methodArgument.add(resultName);
-              }
-              final String call =
-                  'api.${method.name}(${methodArgument.join(', ')})';
-              if (method.isAsynchronous) {
-                indent.writeln('$call;');
-              } else if (method.returnType.isVoid) {
-                indent.writeln('$call;');
-                indent.writeln('wrapped.add(0, null);');
-              } else {
-                indent.writeln('$returnType output = $call;');
-                indent.writeln('wrapped.add(0, output);');
-              }
-            }, addTrailingNewline: false);
-            indent.add(' catch (Error | RuntimeException exception) ');
-            indent.addScoped('{', '}', () {
-              indent.writeln(
-                  'ArrayList<Object> wrappedError = wrapError(exception);');
-              if (method.isAsynchronous) {
-                indent.writeln('reply.reply(wrappedError);');
-              } else {
-                indent.writeln('wrapped = wrappedError;');
-              }
-            });
-            if (!method.isAsynchronous) {
+              methodArgument.add(resultName);
+            }
+            final String call =
+                'api.${method.name}(${methodArgument.join(', ')})';
+            if (method.isAsynchronous) {
+              indent.writeln('$call;');
+            } else {
+              indent.write('try ');
+              indent.addScoped('{', '}', () {
+                if (method.returnType.isVoid) {
+                  indent.writeln('$call;');
+                  indent.writeln('wrapped.add(0, null);');
+                } else {
+                  indent.writeln('$returnType output = $call;');
+                  indent.writeln('wrapped.add(0, output);');
+                }
+              });
+              indent.add(' catch (Throwable exception) ');
+              indent.addScoped('{', '}', () {
+                indent.writeln(
+                    'ArrayList<Object> wrappedError = wrapError(exception);');
+                if (method.isAsynchronous) {
+                  indent.writeln('reply.reply(wrappedError);');
+                } else {
+                  indent.writeln('wrapped = wrappedError;');
+                }
+              });
               indent.writeln('reply.reply(wrapped);');
             }
           });
@@ -765,22 +771,48 @@ Result<$returnType> $resultName =
     });
   }
 
+  void _writeErrorClass(Indent indent) {
+    indent.write('public static class FlutterError extends RuntimeException ');
+    indent.addScoped('{', '}', () {
+      indent.writeln('public final String code;');
+      indent.writeln('public final String message;');
+      indent.writeln('public final Object details;');
+      indent.newln();
+      indent.writeln(
+          'public FlutterError(@NonNull String code, @Nullable String message, @Nullable Object details) ');
+      indent.writeScoped('{', '}', () {
+        indent.writeln('super(message);');
+        indent.writeln('this.code = code;');
+        indent.writeln('this.message = message;');
+        indent.writeln('this.details = details;');
+      });
+    });
+  }
+
   void _writeWrapError(Indent indent) {
     indent.format('''
 @NonNull
 private static ArrayList<Object> wrapError(@NonNull Throwable exception) {
 \tArrayList<Object> errorList = new ArrayList<Object>(3);
-\terrorList.add(exception.toString());
-\terrorList.add(exception.getClass().getSimpleName());
-\terrorList.add(
-\t\t"Cause: " + exception.getCause() + ", Stacktrace: " + Log.getStackTraceString(exception));
+\tif (exception instanceof FlutterError) {
+\t\tFlutterError error = (FlutterError) exception;
+\t\terrorList.add(error.code);
+\t\terrorList.add(error.message);
+\t\terrorList.add(error.details);
+\t} else {
+\t\terrorList.add(exception.toString());
+\t\terrorList.add(exception.getClass().getSimpleName());
+\t\terrorList.add(
+\t\t\t"Cause: " + exception.getCause() + ", Stacktrace: " + Log.getStackTraceString(exception));
+\t}
 \treturn errorList;
 }''');
   }
 
   @override
   void writeGeneralUtilities(
       JavaOptions generatorOptions, Root root, Indent indent) {
+    _writeErrorClass(indent);
     _writeWrapError(indent);
   }
 

packages/pigeon/lib/kotlin_generator.dart

@@ -28,23 +28,25 @@ const DocumentCommentSpecification _docCommentSpec =
 /// Options that control how Kotlin code will be generated.
 class KotlinOptions {
   /// Creates a [KotlinOptions] object
-  const KotlinOptions({
-    this.package,
-    this.copyrightHeader,
-  });
+  const KotlinOptions(
+      {this.package, this.copyrightHeader, this.errorClassName});
 
   /// The package where the generated class will live.
   final String? package;
 
   /// A copyright header that will get prepended to generated code.
   final Iterable<String>? copyrightHeader;
 
+  /// The name of the error class used for passing custom error parameters.
+  final String? errorClassName;
+
   /// Creates a [KotlinOptions] from a Map representation where:
   /// `x = KotlinOptions.fromMap(x.toMap())`.
   static KotlinOptions fromMap(Map<String, Object> map) {
     return KotlinOptions(
       package: map['package'] as String?,
       copyrightHeader: map['copyrightHeader'] as Iterable<String>?,
+      errorClassName: map['errorClassName'] as String?,
     );
   }
 
@@ -54,6 +56,7 @@ class KotlinOptions {
     final Map<String, Object> result = <String, Object>{
       if (package != null) 'package': package!,
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
+      if (errorClassName != null) 'errorClassName': errorClassName!,
     };
     return result;
   }
@@ -404,6 +407,7 @@ class KotlinGenerator extends StructuredGenerator<KotlinOptions> {
   ///     fun setUp(binaryMessenger: BinaryMessenger, api: Api) {...}
   ///   }
   /// }
+  ///
   @override
   void writeHostApi(
     KotlinOptions generatorOptions,
@@ -552,7 +556,7 @@ class KotlinGenerator extends StructuredGenerator<KotlinOptions> {
                         indent.writeln('wrapped = listOf<Any?>($call)');
                       }
                     }, addTrailingNewline: false);
-                    indent.add(' catch (exception: Error) ');
+                    indent.add(' catch (exception: Throwable) ');
                     indent.addScoped('{', '}', () {
                       indent.writeln('wrapped = wrapError(exception)');
                     });
@@ -625,25 +629,49 @@ class KotlinGenerator extends StructuredGenerator<KotlinOptions> {
     });
   }
 
-  void _writeWrapError(Indent indent) {
+  void _writeWrapError(KotlinOptions generatorOptions, Indent indent) {
     indent.newln();
-    indent.write('private fun wrapError(exception: Throwable): List<Any> ');
+    indent.write('private fun wrapError(exception: Throwable): List<Any?> ');
     indent.addScoped('{', '}', () {
-      indent.write('return ');
-      indent.addScoped('listOf<Any>(', ')', () {
-        indent.writeln('exception.javaClass.simpleName,');
-        indent.writeln('exception.toString(),');
-        indent.writeln(
-            '"Cause: " + exception.cause + ", Stacktrace: " + Log.getStackTraceString(exception)');
+      indent.write(
+          'if (exception is ${generatorOptions.errorClassName ?? "FlutterError"}) ');
+      indent.addScoped('{', '}', () {
+        indent.write('return ');
+        indent.addScoped('listOf(', ')', () {
+          indent.writeln('exception.code,');
+          indent.writeln('exception.message,');
+          indent.writeln('exception.details');
+        });
+      }, addTrailingNewline: false);
+      indent.addScoped(' else {', '}', () {
+        indent.write('return ');
+        indent.addScoped('listOf(', ')', () {
+          indent.writeln('exception.javaClass.simpleName,');
+          indent.writeln('exception.toString(),');
+          indent.writeln(
+              '"Cause: " + exception.cause + ", Stacktrace: " + Log.getStackTraceString(exception)');
+        });
       });
     });
   }
 
+  void _writeErrorClass(KotlinOptions generatorOptions, Indent indent) {
+    indent.newln();
+    indent.write('class ${generatorOptions.errorClassName ?? "FlutterError"} ');
+    indent.addScoped('(', ')', () {
+      indent.writeln('val code: String,');
+      indent.writeln('override val message: String? = null,');
+      indent.writeln('val details: Any? = null');
+    }, addTrailingNewline: false);
+    indent.addln(' : Throwable()');
+  }
+
   @override
   void writeGeneralUtilities(
       KotlinOptions generatorOptions, Root root, Indent indent) {
     _writeWrapResult(indent);
-    _writeWrapError(indent);
+    _writeWrapError(generatorOptions, indent);
+    _writeErrorClass(generatorOptions, indent);
   }
 }
 

packages/pigeon/lib/pigeon_lib.dart

@@ -633,6 +633,7 @@ class KotlinGeneratorAdapter implements GeneratorAdapter {
     KotlinOptions kotlinOptions =
         options.kotlinOptions ?? const KotlinOptions();
     kotlinOptions = kotlinOptions.merge(KotlinOptions(
+        errorClassName: kotlinOptions.errorClassName ?? 'FlutterError',
         copyrightHeader: options.copyrightHeader != null
             ? _lineReader(options.copyrightHeader!)
             : null));

packages/pigeon/mock_handler_tester/test/message.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v9.0.1), do not edit directly.
+// Autogenerated from Pigeon (v9.0.2), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name, unnecessary_import
 

packages/pigeon/mock_handler_tester/test/test.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Autogenerated from Pigeon (v9.0.1), do not edit directly.
+// Autogenerated from Pigeon (v9.0.2), do not edit directly.
 // See also: https://pub.dev/packages/pigeon
 // ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, unnecessary_import
 // ignore_for_file: avoid_relative_lib_imports