CORDA-2264 enable appending enum constants (#4347)

* CORDA-2264 enable appending enum constants

* Remove paths B and C, rename test

serialization/src/main/kotlin/net/corda/serialization/internal/amqp/EvolutionSerializerFactory.kt

@@ -149,14 +149,18 @@ class DefaultEvolutionSerializerFactory(
 
         val conversions = members.associate { it to findLocal(it) }
         val convertedOrdinals = remoteOrdinals.asSequence().map { (member, ord) -> ord to conversions[member]!! }.toMap()
-        if (localOrdinals.any { (name, ordinal) -> convertedOrdinals[ordinal] != name })
+
-            throw EvolutionSerializationException(
+        if (constantsAreReordered(localOrdinals, convertedOrdinals)) throw EvolutionSerializationException(this,
-                    this,
                 "Constants have been reordered, additions must be appended to the end")
 
         return EnumEvolutionSerializer(localTypeInformation.observedType, localSerializerFactory, conversions, localOrdinals)
     }
 
+    private fun constantsAreReordered(localOrdinals: Map<String, Int>, convertedOrdinals: Map<Int, String>): Boolean =
+        if (localOrdinals.size <= convertedOrdinals.size) {
+            localOrdinals.any { (name, ordinal) -> convertedOrdinals[ordinal] != name }
+        } else convertedOrdinals.any { (ordinal, name) -> localOrdinals[name] != ordinal }
+
     private fun RemoteTypeInformation.Composable.buildComposableEvolutionSerializer(
             localTypeInformation: LocalTypeInformation.Composable,
             constructor: LocalConstructorInformation,

serialization/src/test/kotlin/net/corda/serialization/internal/amqp/EnumEvolveTests.kt

@@ -13,6 +13,7 @@ import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatThrownBy
 import org.junit.Ignore
 import org.junit.Test
+import java.io.File
 import java.io.NotSerializableException
 import java.net.URI
 import kotlin.test.assertEquals
@@ -424,4 +425,33 @@ class EnumEvolveTests {
                     EvolvabilityTests::class.java.getResource(resource).readBytes()))
         }.isInstanceOf(NotSerializableException::class.java)
     }
+
+    // Version of the class as it was serialised
+    //
+    // enum class ExtendedEnum { A, B, C }
+    //
+    // Version of the class as it's used in the test
+    @CordaSerializationTransformEnumDefaults (
+            CordaSerializationTransformEnumDefault("E", "C"),
+            CordaSerializationTransformEnumDefault("D", "C")
+    )
+    enum class ExtendedEnum { A, B, C, D, E}
+
+    // See https://r3-cev.atlassian.net/browse/CORDA-2264.
+    @Test
+    fun extendEnum() {
+        val resource = "${javaClass.simpleName}.${testName()}"
+        val sf = testDefaultFactory()
+
+        data class C(val e: ExtendedEnum)
+
+        // Uncomment to re-generate test files
+        // val so = SerializationOutput(sf)
+        // File(URI("$localPath/$resource.A")).writeBytes(so.serialize(C(ExtendedEnum.A)).bytes)
+
+        val path1 = EvolvabilityTests::class.java.getResource("$resource.A")
+
+        val obj1 = DeserializationInput(sf).deserialize(SerializedBytes<C>(File(path1.toURI()).readBytes()))
+        assertEquals(ExtendedEnum.A, obj1.e)
+    }
 }