Fix jrubyGH-2182 on jruby-1_7

core/src/main/java/org/jruby/RubyStruct.java

@@ -556,7 +556,14 @@ private IRubyObject inspectStruct(final ThreadContext context) {
             // FIXME: MRI has special case for constants here
             buffer.append(RubyString.objAsString(context, member.eltInternal(i)).getByteList());
             buffer.append('=');
-            buffer.append(inspect(context, values[i]).getByteList());
+            RubyString valueInspect = inspect(context, values[i]);
+            if (valueInspect.isAsciiOnly()) {
+                buffer.append(valueInspect.getByteList());
+            } else {
+                String str = ByteList.decode(buffer.bytes(), buffer.getEncoding().getCharsetName());
+                str += valueInspect;
+                buffer = new ByteList(str.getBytes(), valueInspect.getByteList().getEncoding());
+            }
         }
 
         buffer.append('>');

spec/regression/GH-2182_struct_inspect_has_ascii_encoding_spec.rb

@@ -0,0 +1,20 @@
+# -*- encoding: utf-8 -*-
+
+# https://github.com/jruby/jruby/issues/2182
+if RUBY_VERSION > '1.9'
+  describe 'Struct#inspect' do
+    it 'returns correct value' do
+      s1 = Struct.new(:aa).new("ΆἅἇἈ")
+      s1.inspect.should == "#<struct aa=\"ΆἅἇἈ\">"
+      s1.inspect.encoding.should == Encoding::UTF_8
+
+      s2 = Struct.new(:a, :b).new("ΆἅἇἈ", "abc")
+      s2.inspect.should == "#<struct a=\"ΆἅἇἈ\", b=\"abc\">"
+      s2.inspect.encoding.should == Encoding::UTF_8
+
+      s3 = Struct.new(:b).new("abc")
+      s3.inspect.should == "#<struct b=\"abc\">"
+      s3.inspect.encoding.should == Encoding::ASCII_8BIT
+    end
+  end
+end