Add failing tests case for #426

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/dataformat/xml/failing/PolymorphicList426Test.java

@@ -0,0 +1,112 @@
+package com.fasterxml.jackson.dataformat.xml.failing;
+
+import java.io.IOException;
+import java.util.List;
+
+import com.fasterxml.jackson.annotation.*;
+
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver;
+import com.fasterxml.jackson.databind.jsontype.impl.TypeIdResolverBase;
+
+import com.fasterxml.jackson.dataformat.xml.XmlTestBase;
+import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
+import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
+
+public class PolymorphicList426Test extends XmlTestBase
+{
+    static class Auto {
+        @JacksonXmlProperty(localName = "Object")
+        @JacksonXmlElementWrapper(useWrapping = false)
+//        @JsonInclude(JsonInclude.Include.NON_EMPTY)
+        public List<CarParts> carParts;
+    }
+
+    @JsonTypeIdResolver(CarPartsResolver.class)
+    @JsonTypeInfo(use = JsonTypeInfo.Id.CUSTOM, include = JsonTypeInfo.As.PROPERTY, property = "type")
+    abstract static class CarParts {
+        @JacksonXmlProperty(isAttribute = true) // The is triggering the issue.
+        public String uid;
+    
+        @JacksonXmlProperty(localName = "Object")
+        @JacksonXmlElementWrapper(useWrapping = false)
+//        @JsonInclude(JsonInclude.Include.NON_EMPTY)
+        public List<CarParts> carParts;
+    }
+
+    static class Engine extends CarParts{}
+    static class Chassis extends CarParts{}
+    static class Motor extends CarParts{}
+    static class Body extends CarParts{}
+
+    static class CarPartsResolver extends TypeIdResolverBase {
+        private JavaType superType;
+
+        @Override
+        public void init(JavaType javaType) {
+            this.superType = javaType;
+        }
+
+        @Override
+        public String idFromValue(Object o) {
+            return idFromValueAndType(o, o.getClass());
+        }
+
+        @Override
+        public String idFromValueAndType(Object o, Class<?> aClass) {
+            return aClass.getSimpleName();
+        }
+
+        @Override
+        public JavaType typeFromId(DatabindContext context, String id) throws IOException {
+            Class<?> subType = null;
+            switch (id) {
+                case "Engine": subType = Engine.class; break;
+                case "Chassis": subType = Chassis.class; break;
+                case "Motor": subType = Motor.class; break;
+                case "Body": subType = Body.class; break;
+            }
+            return context.constructSpecializedType(superType, subType);
+        }
+
+        @Override
+        public JsonTypeInfo.Id getMechanism() {
+            return JsonTypeInfo.Id.CUSTOM;
+        }
+    }
+
+    /*
+    /********************************************************
+    /* Test methods
+    /********************************************************
+     */
+
+    private final ObjectMapper MAPPER = newMapper();
+
+    // [dataformat-xml#426]
+    public void testPolymorphicList426() throws Exception
+    {
+        String xml = "" +
+                "<Auto>\n" +
+                "    <Object uid=\"1\" type=\"Engine\">\n" +
+                "        <Object uid=\"2\" type=\"Chassis\"></Object>\n" +
+                "        <Object uid=\"3\" type=\"Motor\"></Object>\n" +
+                "    </Object>\n" +
+                "    <Object uid=\"4\" type=\"Body\"></Object>\n" +
+                "</Auto>";
+        Auto result = MAPPER.readValue(xml, Auto.class);
+        assertNotNull(result);
+        assertNotNull(result.carParts);
+        assertEquals(2, result.carParts.size());
+        CarParts cp = result.carParts.get(0);
+
+        // for debugging:
+//System.err.println("XML:\n"+MAPPER.writeValueAsString(result));        
+
+        assertNotNull(cp);
+        assertNotNull(cp.carParts);
+
+        // So far so good, but fails here:
+        assertEquals(2, cp.carParts.size());
+    }
+}