Serializer Problem with unordered groups

[cdietrich]

Searializer behaves wrong for unordered groups

serializing existing models with unordered groups and adding a new element to an existing * part leads to an invalid model

Model:
	'model' site=ID '{'
        (
            xxxxValue=XXXXValue? &
            properties+=PropertyAssignment*
        )
    '}'
;	
XXXXValue:
    "xxxx" "=" value=INT
;

PropertyAssignment:
    name=ID "=" value=INT
;

import com.google.inject.Inject
import org.eclipse.xtext.serializer.ISerializer
import org.eclipse.xtext.testing.InjectWith
import org.eclipse.xtext.testing.XtextRunner
import org.eclipse.xtext.testing.util.ParseHelper
import org.junit.Assert
import org.junit.Test
import org.junit.runner.RunWith
import org.xtext.example.mydsl3.myDsl.Model
import org.xtext.example.mydsl3.myDsl.MyDslFactory

import static org.junit.Assert.assertEquals

@RunWith(XtextRunner)
@InjectWith(MyDslInjectorProvider)
class MyDslParsingTest{

	@Inject
	ParseHelper<Model> parseHelper
	
	@Inject extension ISerializer serializer

	@Test 
	def void loadModel() {
		val result = parseHelper.parse('''
			model mymodel {
			    yyyy = 1
			    xxxx = 2
			}
		''')
		Assert.assertNotNull(result)
		println(result.eResource.errors)
		result.properties += MyDslFactory.eINSTANCE.createPropertyAssignment => [
		    name = "xxxxx"
		    value = 1
		]
		
		val ser = result.serialize
		println(ser)
		println(parseHelper.parse(ser).eResource.errors)
		assertEquals(0, parseHelper.parse(ser).eResource.errors.size)
	}

}

[cdietrich]

workaround: throw away node model before serializing

https://github.com/eclipse/xtext-core/blob/f9b6d1bebe09dc5775d45671d255384a8160015c/org.eclipse.xtext.testing/src/org/eclipse/xtext/testing/serializer/SerializerTestHelper.java#L145