4 files changed, 48 insertions, 7 deletions
diff --git a/ruby/ext/google/protobuf_c/message.c b/ruby/ext/google/protobuf_c/message.c
index ebe2f1ab..283939c9 100644
--- a/ruby/ext/google/protobuf_c/message.c
+++ b/ruby/ext/google/protobuf_c/message.c
@@ -166,7 +166,7 @@ VALUE Message_method_missing(int argc, VALUE* argv, VALUE _self) {
                                           name, name_len);
 
   if (f == NULL) {
-    rb_raise(rb_eArgError, "Unknown field");
+    return rb_call_super(argc, argv);
   }
 
   if (setter) {
@@ -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++) {
diff --git a/ruby/ext/google/protobuf_c/upb.c b/ruby/ext/google/protobuf_c/upb.c
index 048a163a..9e6aa674 100644
--- a/ruby/ext/google/protobuf_c/upb.c
+++ b/ruby/ext/google/protobuf_c/upb.c
@@ -8537,7 +8537,7 @@ bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max) {
 **       to perfectly match the output of reference encoders that always use the
 **       optimal amount of space for each length.
 **
-**   (2) requires guessing the the size upfront, and if multiple lengths are
+**   (2) requires guessing the size upfront, and if multiple lengths are
 **       guessed wrong the minimum required number of memmove() operations may
 **       be complicated to compute correctly.  Implemented properly, it may have
 **       a useful amortized or average cost, but more investigation is required
diff --git a/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java b/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java
index 547ab22c..39213c4d 100644
--- a/ruby/src/main/java/com/google/protobuf/jruby/RubyMessage.java
+++ b/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.newTypeError("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 {
@@ -217,6 +217,9 @@ public class RubyMessage extends RubyObject {
             RubyDescriptor rubyDescriptor = (RubyDescriptor) getDescriptor(context, metaClass);
             IRubyObject oneofDescriptor = rubyDescriptor.lookupOneof(context, args[0]);
             if (oneofDescriptor.isNil()) {
+                if (!hasField(args[0])) {
+                    return Helpers.invokeSuper(context, this, metaClass, "method_missing", args, Block.NULL_BLOCK);
+                }
                 return index(context, args[0]);
             }
             RubyOneofDescriptor rubyOneofDescriptor = (RubyOneofDescriptor) oneofDescriptor;
@@ -233,6 +236,10 @@ public class RubyMessage extends RubyObject {
             if (field.end_with_p(context, equalSign).isTrue()) {
                 field.chomp_bang(context, equalSign);
             }
+
+            if (!hasField(field)) {
+                return Helpers.invokeSuper(context, this, metaClass, "method_missing", args, Block.NULL_BLOCK);
+            }
             return indexSet(context, field, args[1]);
         }
     }
@@ -435,6 +442,11 @@ public class RubyMessage extends RubyObject {
         return ret;
     }
 
+    private boolean hasField(IRubyObject fieldName) {
+        String nameStr = fieldName.asJavaString();
+        return this.descriptor.findFieldByName(Utils.escapeIdentifier(nameStr)) != null;
+    }
+
     private void checkRepeatedFieldType(ThreadContext context, IRubyObject value,
                                         Descriptors.FieldDescriptor fieldDescriptor) {
         Ruby runtime = context.runtime;
diff --git a/ruby/tests/basic.rb b/ruby/tests/basic.rb
index 40c20078..da85520f 100644
--- a/ruby/tests/basic.rb
+++ b/ruby/tests/basic.rb
@@ -191,6 +191,35 @@ module BasicTest
       assert m1.hash != m2.hash
     end
 
+    def test_unknown_field_errors
+      e = assert_raise NoMethodError do
+        TestMessage.new.hello
+      end
+      assert_match(/hello/, e.message)
+
+      e = assert_raise NoMethodError do
+        TestMessage.new.hello = "world"
+      end
+      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