Add test for xsi:nil hierarchy bug (#366)

src/test/java/com/fasterxml/jackson/dataformat/xml/deser/XsiNil354Test.java

@@ -14,6 +14,20 @@ public DoubleWrapper(Double value) {
         }
     }
 
+    protected static class Parent {
+        public Level1 level1;
+    }
+
+    protected static class Level1 {
+        public Level2 level2;
+        public String field; // this should not be needed, but an unknown element is thrown without it
+    }
+
+    protected static class Level2 {
+        public String ignored;
+        public String field;
+    }
+
     private final XmlMapper MAPPER = newMapper();
 
     public void testWithDoubleAsNull() throws Exception
@@ -29,7 +43,7 @@ public void testWithDoubleAsNull() throws Exception
                 DoubleWrapper.class);
         assertNotNull(bean);
         assertNull(bean.d);
-        
+
         // actually we should perhaps also verify there is no content but... for now, let's leave it.
     }
 
@@ -57,4 +71,25 @@ public void testRootPojoAsNonNull() throws Exception
                 Point.class);
         assertNotNull(bean);
     }
+
+    public void testDoesNotAffectHierarchy() throws Exception
+    {
+        String xml = "<Parent xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">"
+                + "<level1>"
+                + "<level2>"
+                + "<ignored xsi:nil=\"true\"/>"
+                + "<field>test-value</field>"
+                + "</level2>"
+                + "</level1>"
+                + "</Parent>";
+        Parent bean = MAPPER.readValue(xml, Parent.class);
+
+        assertNotNull(bean);
+
+        // this should not be set, but having an xsi:nil field before it causes it to set the next field on the wrong class
+        assertEquals("test-value", bean.level1.field);
+
+        // fails because field is set on level1 instead of on level2
+        assertEquals("test-value", bean.level1.level2.field);
+    }
 }