Generate constructor arguments again, add a flag to disable

protoc_plugin/CHANGELOG.md

@@ -1,3 +1,15 @@
+## 21.0.3
+
+* New protoc_plugin flag `generate_constructor_arguments` added to bring back
+  the old message factory methods with arguments. These arguments were removed
+  in 21.0.0 ([#703]) as they caused bloat in generated binaries in some cases.
+
+  Example usage:
+
+  ```
+  protoc --dart_out='generate_constructor_arguments,<other options>:.' ...
+  ```
+
 ## 21.0.2
 
 * Fix missing protobuf import in generated grpc files. ([#844])

protoc_plugin/lib/src/base_type.dart

@@ -56,6 +56,9 @@ class BaseType {
   String getRepeatedDartType(FileGenerator fileGen) =>
       '$coreImportPrefix.List<${getDartType(fileGen)}>';
 
+  String getRepeatedDartTypeIterable(FileGenerator fileGen) =>
+      '$coreImportPrefix.Iterable<${getDartType(fileGen)}>';
+
   factory BaseType(FieldDescriptorProto field, GenerationContext ctx) {
     String constSuffix;
 

protoc_plugin/lib/src/message_generator.dart

@@ -324,7 +324,8 @@ class MessageGenerator extends ProtobufContainer {
       NamedLocation(
           name: classname, fieldPathSegment: fieldPath, start: 'class '.length)
     ], () {
-      out.println('factory $classname() => create();');
+      _generateFactory(out);
+
       out.printlnAnnotated('$classname._() : super();', [
         NamedLocation(name: classname, fieldPathSegment: fieldPath, start: 0)
       ]);
@@ -424,6 +425,51 @@ class MessageGenerator extends ProtobufContainer {
     out.println();
   }
 
+  void _generateFactory(IndentingWriter out) {
+    if (fileGen.options.generateConstructorArguments) {
+      out.print('factory $classname(');
+      if (_fieldList.isNotEmpty) {
+        out.println('{');
+        for (final field in _fieldList) {
+          _emitDeprecatedIf(field.isDeprecated, out);
+          if (field.isRepeated && !field.isMapField) {
+            out.println(
+                '  ${field.baseType.getRepeatedDartTypeIterable(fileGen)}? ${field.memberNames!.fieldName},');
+          } else {
+            out.println(
+                '  ${field.getDartType()}? ${field.memberNames!.fieldName},');
+          }
+        }
+        out.print('}');
+      }
+      if (_fieldList.isNotEmpty) {
+        out.println(') {');
+        out.println('  final _result = create();');
+        for (final field in _fieldList) {
+          out.println('  if (${field.memberNames!.fieldName} != null) {');
+          if (field.isDeprecated) {
+            out.println(
+                '    // ignore: deprecated_member_use_from_same_package');
+          }
+          if (field.isRepeated || field.isMapField) {
+            out.println(
+                '    _result.${field.memberNames!.fieldName}.addAll(${field.memberNames!.fieldName});');
+          } else {
+            out.println(
+                '    _result.${field.memberNames!.fieldName} = ${field.memberNames!.fieldName};');
+          }
+          out.println('  }');
+        }
+        out.println('  return _result;');
+        out.println('}');
+      } else {
+        out.println(') => create();');
+      }
+    } else {
+      out.println('factory $classname() => create();');
+    }
+  }
+
   // Returns true if the message type has any required fields.  If it doesn't,
   // we can optimize out calls to its isInitialized()/_findInvalidFields()
   // methods.

protoc_plugin/lib/src/options.dart

@@ -50,8 +50,12 @@ bool genericOptionsParser(CodeGeneratorRequest request,
 class GenerationOptions {
   final bool useGrpc;
   final bool generateMetadata;
+  final bool generateConstructorArguments;
 
-  GenerationOptions({this.useGrpc = false, this.generateMetadata = false});
+  GenerationOptions(
+      {this.useGrpc = false,
+      this.generateMetadata = false,
+      this.generateConstructorArguments = false});
 }
 
 /// A parser for a name-value pair option. Options parsed in
@@ -84,13 +88,27 @@ class GenerateMetadataParser implements SingleOptionParser {
   @override
   void parse(String name, String? value, OnError onError) {
     if (value != null) {
-      onError('Invalid metadata option. No value expected.');
+      onError('Invalid generate_kythe_info option. No value expected.');
       return;
     }
     generateKytheInfo = true;
   }
 }
 
+class GenerateConstructorArgumentsParser implements SingleOptionParser {
+  bool generateConstructorArguments = false;
+
+  @override
+  void parse(String name, String? value, OnError onError) {
+    if (value != null) {
+      onError(
+          'Invalid generate_constructor_arguments option. No value expected.');
+      return;
+    }
+    generateConstructorArguments = true;
+  }
+}
+
 /// Parser used by the compiler, which supports the `rpc` option (see
 /// [GrpcOptionParser]) and any additional option added in [parsers]. If
 /// [parsers] has a key for `rpc`, it will be ignored.
@@ -102,13 +120,21 @@ GenerationOptions? parseGenerationOptions(
 
   final grpcOptionParser = GrpcOptionParser();
   newParsers['grpc'] = grpcOptionParser;
+
   final generateMetadataParser = GenerateMetadataParser();
   newParsers['generate_kythe_info'] = generateMetadataParser;
 
+  final generateConstructorArgumentsParser =
+      GenerateConstructorArgumentsParser();
+  newParsers['generate_constructor_arguments'] =
+      generateConstructorArgumentsParser;
+
   if (genericOptionsParser(request, response, newParsers)) {
     return GenerationOptions(
         useGrpc: grpcOptionParser.grpcEnabled,
-        generateMetadata: generateMetadataParser.generateKytheInfo);
+        generateMetadata: generateMetadataParser.generateKytheInfo,
+        generateConstructorArguments:
+            generateConstructorArgumentsParser.generateConstructorArguments);
   }
   return null;
 }

protoc_plugin/pubspec.yaml

@@ -1,5 +1,5 @@
 name: protoc_plugin
-version: 21.0.2
+version: 21.0.3
 description: A protobuf protoc compiler plugin used to generate Dart code.
 repository: https://github.com/google/protobuf.dart/tree/master/protoc_plugin