Fixed #383

Author: cowtowncoder

release-notes/VERSION

@@ -13,6 +13,8 @@ Project: jackson-databind
  (reported by Starkom@github)
 #357: StackOverflowError with contentConverter that returns array type
  (reported by Florian S)
+#383: Recursive `@JsonUnwrapped` (`child` with same type) fail: "No _valueDeserializer assigned"
+ (reported by tdavis@github)
 #403: Make FAIL_ON_NULL_FOR_PRIMITIVES apply to primitive arrays and other types that wrap primitives
  (reported by Harleen S)
 #476: Allow "Serialize as POJO" using `@JsonFormat(shape=Shape.OBJECT)` class annotation

src/main/java/com/fasterxml/jackson/databind/SerializerProvider.java

@@ -528,6 +528,8 @@ public JsonSerializer<Object> findValueSerializer(Class<?> valueType, BeanProper
      * full generics-aware type instead of raw class.
      * This is necessary for accurate handling of external type information,
      * to handle polymorphic types.
+     *<p>
+     * Note: this call will also contextualize serializer before returning it.
      * 
      * @param property When creating secondary serializers, property for which
      *   serializer is needed: annotations of the property (or bean that contains it)

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

@@ -39,6 +39,14 @@ public class BeanDeserializer
      */
     protected transient Exception _nullFromCreator;
 
+    /**
+     * State marker we need in order to avoid infinite recursion for some cases
+     * (not very clean, alas, but has to do for now)
+     *
+     * @since 2.9
+     */
+    private volatile transient NameTransformer _currentlyTransforming;
+
     /*
     /**********************************************************
     /* Life-cycle, construction, initialization
@@ -86,18 +94,22 @@ public BeanDeserializer(BeanDeserializerBase src, BeanPropertyMap props) {
     }
 
     @Override
-    public JsonDeserializer<Object> unwrappingDeserializer(NameTransformer unwrapper)
+    public JsonDeserializer<Object> unwrappingDeserializer(NameTransformer transformer)
     {
         // bit kludgy but we don't want to accidentally change type; sub-classes
         // MUST override this method to support unwrapped properties...
         if (getClass() != BeanDeserializer.class) {
             return this;
         }
-        /* main thing really is to just enforce ignoring of unknown
-         * properties; since there may be multiple unwrapped values
-         * and properties for all may be interleaved...
-         */
-        return new BeanDeserializer(this, unwrapper);
+        // 25-Mar-2017, tatu: Not clean at all, but for [databind#383] we do need
+        //   to keep track of accidental recursion...
+        if (_currentlyTransforming == transformer) {
+            return this;
+        }
+        _currentlyTransforming = transformer;
+        try {
+            return new BeanDeserializer(this, transformer);
+        } finally { _currentlyTransforming = null; }
     }
 
     @Override

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

@@ -478,18 +478,23 @@ public void resolve(DeserializationContext ctxt)
                 prop = _resolvedObjectIdProperty(ctxt, prop);
             }
             // Support unwrapped values (via @JsonUnwrapped)
-            SettableBeanProperty u = _resolveUnwrappedProperty(ctxt, prop);
-            if (u != null) {
-                prop = u;
-                if (unwrapped == null) {
-                    unwrapped = new UnwrappedPropertyHandler();
+            NameTransformer xform = _findPropertyUnwrapper(ctxt, prop);
+            if (xform != null) {
+                JsonDeserializer<Object> orig = prop.getValueDeserializer();
+                JsonDeserializer<Object> unwrapping = orig.unwrappingDeserializer(xform);
+                if (unwrapping != orig && unwrapping != null) {
+                    prop = prop.withValueDeserializer(unwrapping);
+                    if (unwrapped == null) {
+                        unwrapped = new UnwrappedPropertyHandler();
+                    }
+                    unwrapped.addProperty(prop);
+                    // 12-Dec-2014, tatu: As per [databind#647], we will have problems if
+                    //    the original property is left in place. So let's remove it now.
+                    // 25-Mar-2017, tatu: Wonder if this could be problematic wrt creators?
+                    //    (that is, should be remove it from creator too)
+                    _beanProperties.remove(prop);
+                    continue;
                 }
-                unwrapped.addProperty(prop);
-                // 12-Dec-2014, tatu: As per [databind#647], we will have problems if
-                //    the original property is left in place. So let's remove it now.
-                // 25-Mar-2017, tatu: Wonder if this could be problematic wrt creators?
-                _beanProperties.remove(prop);
-                continue;
             }
 
             // 26-Oct-2016, tatu: Need to have access to value deserializer to know if
@@ -796,7 +801,7 @@ protected SettableBeanProperty _resolvedObjectIdProperty(DeserializationContext
      * Helper method called to see if given property might be so-called unwrapped
      * property: these require special handling.
      */
-    protected SettableBeanProperty _resolveUnwrappedProperty(DeserializationContext ctxt,
+    protected NameTransformer _findPropertyUnwrapper(DeserializationContext ctxt,
             SettableBeanProperty prop)
         throws JsonMappingException
     {
@@ -811,13 +816,7 @@ protected SettableBeanProperty _resolveUnwrappedProperty(DeserializationContext
                             "Can not define Creator property \"%s\" as `@JsonUnwrapped`: combination not yet supported",
                             prop.getName()));
                 }
-                
-                JsonDeserializer<Object> orig = prop.getValueDeserializer();
-                JsonDeserializer<Object> unwrapping = orig.unwrappingDeserializer(unwrapper);
-                if (unwrapping != orig && unwrapping != null) {
-                    // might be cleaner to create new instance; but difficult to do reliably, so:
-                    return prop.withValueDeserializer(unwrapping);
-                }
+                return unwrapper;
             }
         }
         return null;

src/test/java/com/fasterxml/jackson/failing/TestUnwrappedRecursive383.java renamed to src/test/java/com/fasterxml/jackson/databind/struct/TestUnwrappedRecursive383.java

@@ -1,4 +1,4 @@
-package com.fasterxml.jackson.failing;
+package com.fasterxml.jackson.databind.struct;
 
 import com.fasterxml.jackson.annotation.*;