Merge branch '2.10' into 2.11

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -52,6 +52,8 @@ Project: jackson-databind
 #2602: ByteBufferSerializer produces unexpected results with a duplicated ByteBuffer
   and a position > 0
  (reported by Eduard T)
+#2605: Failure to deserializer polymorphic subtypes of base type `Enum`
+ (reported by uewle@github)
 #2610: `EXTERNAL_PROPERTY` doesn't work with `@JsonIgnoreProperties`
  (reported, fix suggested by Alexander S)
 

src/main/java/com/fasterxml/jackson/databind/deser/BasicDeserializerFactory.java

@@ -1460,6 +1460,15 @@ public JsonDeserializer<?> createEnumDeserializer(DeserializationContext ctxt,
         JsonDeserializer<?> deser = _findCustomEnumDeserializer(enumClass, config, beanDesc);
 
         if (deser == null) {
+            // 12-Feb-2020, tatu: while we can't really create real deserializer for `Enum.class`,
+            //    it is necessary to allow it in one specific case: see [databind#2605] for details
+            //    but basically it can be used as polymorphic base.
+            //    We could check `type.getTypeHandler()` to look for that case but seems like we
+            //    may as well simply create placeholder (AbstractDeserializer) regardless
+            if (enumClass == Enum.class) {
+                return AbstractDeserializer.constructForNonPOJO(beanDesc);
+            }
+
             ValueInstantiator valueInstantiator = _constructDefaultValueInstantiator(ctxt, beanDesc);
             SettableBeanProperty[] creatorProps = (valueInstantiator == null) ? null
                     : valueInstantiator.getFromObjectArguments(ctxt.getConfig());

src/main/java/com/fasterxml/jackson/databind/deser/DeserializerCache.java

@@ -363,8 +363,11 @@ protected JsonDeserializer<?> _createDeserializer2(DeserializationContext ctxt,
         throws JsonMappingException
     {
         final DeserializationConfig config = ctxt.getConfig();
-        // If not, let's see which factory method to use:
-        if (type.isEnumType()) {
+        // If not, let's see which factory method to use
+
+        // 12-Feb-20202, tatu: Need to ensure that not only all Enum implementations get
+        //    there, but also `Enum` -- latter wrt [databind#2605], polymorphic usage
+        if (ClassUtil.isEnumType(type.getRawClass())) { // type.isEnumType()) {
             return factory.createEnumDeserializer(ctxt, type, beanDesc);
         }
         if (type.isContainerType()) {

src/test/java/com/fasterxml/jackson/databind/jsontype/TestEnumTyping.java

@@ -46,59 +46,82 @@ public void setValue(Object o) {
             value = o;
         }
     }
-    
+
+    // for [databind#2605]
+    static class EnumContaintingClass<ENUM_TYPE extends Enum<ENUM_TYPE>> {
+        @JsonTypeInfo(
+            use = JsonTypeInfo.Id.CLASS,
+            include = JsonTypeInfo.As.PROPERTY,
+            property = "@class"
+        )
+        public ENUM_TYPE selected;
+
+        protected EnumContaintingClass() { }
+
+        public EnumContaintingClass(ENUM_TYPE selected) {
+          this.selected = selected;
+        }
+    }
+
     /*
     /**********************************************************
     /* Unit tests
     /**********************************************************
      */
 
+    private final ObjectMapper MAPPER = newJsonMapper();
+
     public void testTagList() throws Exception
     {
-        ObjectMapper m = new ObjectMapper();
         TagList list = new TagList();
         list.add(Tag.A);
         list.add(Tag.B);
-        String json = m.writeValueAsString(list);
+        String json = MAPPER.writeValueAsString(list);
 
-        TagList result = m.readValue(json, TagList.class);
+        TagList result = MAPPER.readValue(json, TagList.class);
         assertEquals(2, result.size());
         assertSame(Tag.A, result.get(0));
         assertSame(Tag.B, result.get(1));
     }
 
     public void testEnumInterface() throws Exception
     {
-        ObjectMapper m = new ObjectMapper();
-        String json = m.writeValueAsString(Tag.B);
-        EnumInterface result = m.readValue(json, EnumInterface.class);
+        String json = MAPPER.writeValueAsString(Tag.B);
+        EnumInterface result = MAPPER.readValue(json, EnumInterface.class);
         assertSame(Tag.B, result);
     }
 
     public void testEnumInterfaceList() throws Exception
     {
-        ObjectMapper m = new ObjectMapper();
         EnumInterfaceList list = new EnumInterfaceList();
         list.add(Tag.A);
         list.add(Tag.B);
-        String json = m.writeValueAsString(list);
+        String json = MAPPER.writeValueAsString(list);
 
-        EnumInterfaceList result = m.readValue(json, EnumInterfaceList.class);
+        EnumInterfaceList result = MAPPER.readValue(json, EnumInterfaceList.class);
         assertEquals(2, result.size());
         assertSame(Tag.A, result.get(0));
         assertSame(Tag.B, result.get(1));
     }
 
     public void testUntypedEnum() throws Exception
     {
-        ObjectMapper mapper = new ObjectMapper();
-        String str = mapper.writeValueAsString(new UntypedEnumBean(TestEnum.B));
-        UntypedEnumBean result = mapper.readValue(str, UntypedEnumBean.class);
+        String str = MAPPER.writeValueAsString(new UntypedEnumBean(TestEnum.B));
+        UntypedEnumBean result = MAPPER.readValue(str, UntypedEnumBean.class);
         assertNotNull(result);
         assertNotNull(result.value);
         Object ob = result.value;
         assertSame(TestEnum.class, ob.getClass());
         assertEquals(TestEnum.B, result.value);
     }
-    
+
+    // for [databind#2605]
+    public void testRoundtrip() throws Exception
+    {
+        EnumContaintingClass<TestEnum> input = new EnumContaintingClass<TestEnum>(TestEnum.B);
+        String json = MAPPER.writeValueAsString(input);
+//      Object o = MAPPER.readerFor(EnumContaintingClass.class).readValue(json);
+        Object o = MAPPER.readValue(json, EnumContaintingClass.class);
+        assertNotNull(o);
+    }
 }