Add field name to initialization map exceptions

ruby/ext/google/protobuf_c/message.c

@@ -197,7 +197,7 @@ int Message_initialize_kwarg(VALUE key, VALUE val, VALUE _self) {
   f = upb_msgdef_ntofz(self->descriptor->msgdef, name);
   if (f == NULL) {
     rb_raise(rb_eArgError,
-             "Unknown field name in initialization map entry.");
+             "Unknown field name '%s' in initialization map entry.", name);
   }
 
   if (is_map_field(f)) {
@@ -205,7 +205,7 @@ int Message_initialize_kwarg(VALUE key, VALUE val, VALUE _self) {
 
     if (TYPE(val) != T_HASH) {
       rb_raise(rb_eArgError,
-               "Expected Hash object as initializer value for map field.");
+               "Expected Hash object as initializer value for map field '%s'.", name);
     }
     map = layout_get(self->descriptor->layout, Message_data(self), f);
     Map_merge_into_self(map, val);
@@ -214,7 +214,7 @@ int Message_initialize_kwarg(VALUE key, VALUE val, VALUE _self) {
 
     if (TYPE(val) != T_ARRAY) {
       rb_raise(rb_eArgError,
-               "Expected array as initializer value for repeated field.");
+               "Expected array as initializer value for repeated field '%s'.", name);
     }
     ary = layout_get(self->descriptor->layout, Message_data(self), f);
     for (int i = 0; i < RARRAY_LEN(val); i++) {

ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java

@@ -86,14 +86,14 @@ public class RubyMessage extends RubyObject {
 
                     if (Utils.isMapEntry(fieldDescriptor)) {
                         if (!(value instanceof RubyHash))
-                            throw runtime.newArgumentError("Expected Hash object as initializer value for map field.");
+                            throw runtime.newArgumentError("Expected Hash object as initializer value for map field '" +  key.asJavaString() + "'.");
 
                         final RubyMap map = newMapForField(context, fieldDescriptor);
                         map.mergeIntoSelf(context, value);
                         maps.put(fieldDescriptor, map);
                     } else if (fieldDescriptor.isRepeated()) {
                         if (!(value instanceof RubyArray))
-                            throw runtime.newArgumentError("Expected array as initializer var for repeated field.");
+                            throw runtime.newArgumentError("Expected array as initializer value for repeated field '" +  key.asJavaString() + "'.");
                         RubyRepeatedField repeatedField = rubyToRepeatedField(context, fieldDescriptor, value);
                         addRepeatedField(fieldDescriptor, repeatedField);
                     } else {

ruby/tests/basic.rb

@@ -203,6 +203,23 @@ module BasicTest
       assert_match(/hello/, e.message)
     end
 
+    def test_initialization_map_errors
+      e = assert_raise ArgumentError do
+        TestMessage.new(:hello => "world")
+      end
+      assert_match(/hello/, e.message)
+
+      e = assert_raise ArgumentError do
+        MapMessage.new(:map_string_int32 => "hello")
+      end
+      assert_equal e.message, "Expected Hash object as initializer value for map field 'map_string_int32'."
+
+      e = assert_raise ArgumentError do
+        TestMessage.new(:repeated_uint32 => "hello")
+      end
+      assert_equal e.message, "Expected array as initializer value for repeated field 'repeated_uint32'."
+    end
+
     def test_type_errors
       m = TestMessage.new
       assert_raise TypeError do