Rename mixin protos and add a check for undefined mixin name

lib/message_generator.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of protoc;
 
 class MessageGenerator extends ProtobufContainer {
   /// Returns the mixin for this message, or null if none.
   ///
   /// First searches [declaredMixins], then internal mixins declared by
   /// [findMixin].
-  static PbMixin _getMixin(DescriptorProto desc,
+  static PbMixin _getMixin(DescriptorProto desc, FileDescriptorProto file,
       Map<String, PbMixin> declaredMixins, PbMixin defaultMixin) {
-    PbMixin getMixinByName(String name) {
-      if (name.isEmpty) return null; // don't use a mixin (override any default)
-      return declaredMixins[name] ?? findMixin(name);
-    }
-
     if (!desc.hasOptions() || !desc.options.hasExtension(Dart_options.mixin)) {
       return defaultMixin;
     }
 
     String name = desc.options.getExtension(Dart_options.mixin);
-    return getMixinByName(name);
+    if (name.isEmpty) return null; // don't use any mixins (override default)
+    var mixin = declaredMixins[name] ?? findMixin(name);
+    if (mixin == null) {
+      throw throw '${desc.name} in ${file.name}: mixin "$name" not found';

[frederikmutzel, 2016/06/28 08:15:13]

double throw

[skybrian, 2016/06/28 08:40:34]

Fixed.

+    }
+    return mixin;
   }
 
   final String classname;
   final String fqname;
   final PbMixin mixin;
 
   final ProtobufContainer _parent;
   final DescriptorProto _descriptor;
   final List<EnumGenerator> _enumGenerators = <EnumGenerator>[];
   final List<MessageGenerator> _messageGenerators = <MessageGenerator>[];
   final List<ExtensionGenerator> _extensionGenerators = <ExtensionGenerator>[];
 
   // populated by resolve()
   List<ProtobufField> _fieldList;
 
   MessageGenerator(DescriptorProto descriptor, ProtobufContainer parent,
       Map<String, PbMixin> declaredMixins, PbMixin defaultMixin)
       : _descriptor = descriptor,
         _parent = parent,
         classname = (parent.classname == '')
             ? descriptor.name
             : '${parent.classname}_${descriptor.name}',
         fqname = (parent == null || parent.fqname == null)
             ? descriptor.name
             : (parent.fqname == '.'
                 ? '.${descriptor.name}'
                 : '${parent.fqname}.${descriptor.name}'),
-        mixin = _getMixin(descriptor, declaredMixins, defaultMixin) {
+        mixin = _getMixin(descriptor, parent.fileGen.descriptor, declaredMixins,
+            defaultMixin) {
     for (EnumDescriptorProto e in _descriptor.enumType) {
       _enumGenerators.add(new EnumGenerator(e, this));
     }
 
     for (DescriptorProto n in _descriptor.nestedType) {
       _messageGenerators
           .add(new MessageGenerator(n, this, declaredMixins, defaultMixin));
     }
 
     for (FieldDescriptorProto x in _descriptor.extension) {
@@ skipping 317 matching lines @@
 
     for (var m in _messageGenerators) {
       m.generateConstants(out);
     }
 
     for (var e in _enumGenerators) {
       e.generateConstants(out);
     }
   }
 }