Add generic types for strong mode

lib/src/protobuf/field_set.dart

 // Copyright (c) 2015, 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 protobuf;
 
 final _emptyList = new List.unmodifiable([]);
 
 /// All the data in a GeneratedMessage.
 ///
@@ skipping 14 matching lines @@
   _ExtensionFieldSet _extensions;
 
   /// Contains all the unknown fields, or null if there aren't any.
   UnknownFieldSet _unknownFields;
 
   _FieldSet(this._message, BuilderInfo meta, this._eventPlugin)
       : this._meta = meta,
         _values = _makeValueList(meta.fieldInfo);
 
   static _makeValueList(Map<int, FieldInfo> infos) {
-      if (infos.isEmpty) return _emptyList;
-      return new List(infos.length);
+    if (infos.isEmpty) return _emptyList;
+    return new List(infos.length);
   }
 
   // Metadata about multiple fields
 
   String get _messageName => _meta.messageName;
   bool get _isReadOnly => _message._isReadOnly;
   bool get _hasRequiredFields => _meta.hasRequiredFields;
 
   /// The FieldInfo for each non-extension field.
   Iterable<FieldInfo> get _infos => _meta.fieldInfo.values;
@@ skipping 56 matching lines @@
     }
     if (_hasExtensions) {
       var fi = _extensions._getInfoOrNull(tagNumber);
       if (fi != null) {
         return _extensions._getFieldOrDefault(fi);
       }
     }
     throw new ArgumentError("tag $tagNumber not defined in $_messageName");
   }
 
-  _getDefault(FieldInfo fi) {
+  /*T*/ _getDefault/*<T>*/(FieldInfo/*<T>*/ fi) {
     if (!fi.isRepeated) return fi.makeDefault();
     if (_isReadOnly) return _emptyList;
 
     // TODO(skybrian) we could avoid this by generating another
     // method for repeated fields:
     //   msg.mutableFoo().add(123);
-    var value = _message.createRepeatedField(fi.tagNumber, fi);
+    var value = fi._createRepeatedField(_message);
     _setNonExtensionFieldUnchecked(fi, value);
     return value;
   }
 
   _getFieldOrNullByTag(int tagNumber) {
     var fi = _getFieldInfoOrNull(tagNumber);
     if (fi == null) return null;
     return _getFieldOrNull(fi);
   }
 
@@ skipping 74 matching lines @@
       _setNonExtensionFieldUnchecked(fi, value);
     }
   }
 
   /// Returns the list to use for adding to a repeated field.
   ///
   /// Works for both extended and non-extended fields.
   /// Creates and stores the repeated field if it doesn't exist.
   /// If it's an extension and the list doesn't exist, validates and stores it.
   /// Suitable for decoders.
-  List _ensureRepeatedField(FieldInfo fi) {
+  List/*<T>*/ _ensureRepeatedField/*<T>*/(FieldInfo/*<T>*/ fi) {
     assert(!_isReadOnly);
     assert(fi.isRepeated);
     if (fi.index == null) {
       return _ensureExtensions()._ensureRepeatedField(fi);
     }
     var value = _getFieldOrNull(fi);
-    if (value != null) return value;
+    if (value != null) return value as List/*<T>*/;

[Søren Gjesse, 2016/04/01 06:24:28]

This is more a strong mode question.

Why is this explicit cast required? The return type is known, so it could just
be implicit.

[Leaf, 2016/04/01 17:09:56]

We (strong mode) warn on categories of casts that are likely to fail in DDC but
succeed in regular checked mode.  Casting from List<dynamic> to List<NotDynamic>
is one of those categories.  We allow an explicit cast so that you can do the
conversion if you're sure that the runtime value will actually have the right
reified type.

[skybrian, 2016/04/01 18:01:40]

The return type of _getFieldOrNull is dynamic. I tried turning it into a generic
method, but ran into complications, and it didn't seem to make the warning go
away.

 
-    value = _message.createRepeatedField(fi.tagNumber, fi);
-    _setNonExtensionFieldUnchecked(fi, value);
-    return value;
+    var newValue = fi._createRepeatedField(_message);
+    _setNonExtensionFieldUnchecked(fi, newValue);
+    return newValue;
   }
 
   /// Sets a non-extended field and fires events.
   void _setNonExtensionFieldUnchecked(FieldInfo fi, value) {
     if (_hasObservers) {
       _eventPlugin.beforeSetField(fi, value);
     }
     _values[fi.index] = value;
   }
 
   // Generated method implementations
 
   /// The implementation of a generated getter.
-  _$get(int index, int tagNumber, defaultValue) {
+  /*T*/ _$get/*<T>*/(int index, int tagNumber, /*T*/ defaultValue) {
     assert(_nonExtensionInfo(tagNumber).index == index);
     var value = _values[index];
     if (value != null) return value;
     if (defaultValue != null) return defaultValue;
     return _getDefault(_nonExtensionInfo(tagNumber));
   }
 
   /// The implementation of a generated has method.
   bool _$has(int index, int tagNumber) {
     assert(_nonExtensionInfo(tagNumber).index == index);
     var value = _values[index];
     if (value == null) return false;
     if (value is List) return value.isNotEmpty;
     return true;
   }
 
   /// The implementation of a generated setter.
   ///
   /// In production, does no validation other than a null check.
   /// Only handles non-repeated, non-extension fields.
   /// Also, doesn't handle enums or messages which need per-type validation.
   void _$set(int index, int tagNumber, value) {
     assert(_nonExtensionInfo(tagNumber).index == index);
     assert(!_nonExtensionInfo(tagNumber).isRepeated);
     assert(_$check(tagNumber, value));
     if (_isReadOnly) {
       throw new UnsupportedError(
-        "attempted to call a setter on a read-only message ($_messageName)");
+          "attempted to call a setter on a read-only message ($_messageName)");
     }
     if (value == null) {
       _$check(tagNumber, value); // throw exception for null value
     }
     if (_hasObservers) {
       _eventPlugin.beforeSetField(_nonExtensionInfo(tagNumber), value);
     }
     _values[index] = value;
   }
 
@@ skipping 232 matching lines @@
   void _appendInvalidFields(List<String> problems, String prefix) {
     if (!_hasRequiredFields) return;
     for (var fi in _infos) {
       var value = _values[fi.index];
       fi._appendInvalidFields(problems, value, prefix);
     }
     // TODO(skybrian): search extensions as well
     // https://github.com/dart-lang/dart-protobuf/issues/46
   }
 }