Fix #1604

release-notes/VERSION

@@ -5,11 +5,13 @@ Project: jackson-databind
 
 2.8.11 (not yet released)
 
+#1604: Nested type arguments doesn't work with polymorphic types
 #1767: Allow `DeserializationProblemHandler` to respond to primitive types
  (reported by nhtzr@github)
 #1768: Improve `TypeFactory.constructFromCanonical()` to work with
   `java.lang.reflect.Type.getTypeName()` format
 
+
 2.8.10 (24-Aug-2017)
 
 #1657: `StdDateFormat` deserializes dates with no tz/offset as UTC instead of

src/main/java/com/fasterxml/jackson/databind/type/PlaceholderForType.java

@@ -0,0 +1,109 @@
+package com.fasterxml.jackson.databind.type;
+
+import com.fasterxml.jackson.databind.JavaType;
+
+/**
+ * Helper type used when introspecting bindings for already resolved types,
+ * needed for specialization.
+ *
+ * @since 2.8.11
+ */
+public class PlaceholderForType extends TypeBase
+{
+    private static final long serialVersionUID = 1L;
+
+    protected final int _ordinal;
+
+    /**
+     * Type assigned during wildcard resolution (which follows type
+     * structure resolution)
+     */
+    protected JavaType _actualType;
+
+    public PlaceholderForType(int ordinal)
+    {
+        super(Object.class, TypeBindings.emptyBindings(),
+                TypeFactory.unknownType(), null, 1, // super-class, super-interfaces, hashCode
+                null, null, false); // value/type handler, as-static
+        _ordinal = ordinal;
+    }
+
+    public JavaType actualType() { return _actualType; }
+    public void actualType(JavaType t) { _actualType = t; }
+
+    // Override to get better diagnostics
+    @Override
+    protected String buildCanonicalName() {
+        return toString();
+    }
+
+    @Override
+    public StringBuilder getGenericSignature(StringBuilder sb) {
+        return getErasedSignature(sb);
+    }
+
+    @Override
+    public StringBuilder getErasedSignature(StringBuilder sb) {
+        sb.append('$').append(_ordinal+1);
+        return sb;
+    }
+
+    @Override
+    public JavaType withTypeHandler(Object h) {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType withContentTypeHandler(Object h) {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType withValueHandler(Object h) {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType withContentValueHandler(Object h) {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType withContentType(JavaType contentType) {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType withStaticTyping() {
+        return _unsupported();
+    }
+
+    @Override
+    public JavaType refine(Class<?> rawType, TypeBindings bindings, JavaType superClass, JavaType[] superInterfaces) {
+        return _unsupported();
+    }
+
+    @Override
+    protected JavaType _narrow(Class<?> subclass) {
+        return _unsupported();
+    }
+
+    @Override
+    public boolean isContainerType() {
+        return false;
+    }
+
+    @Override
+    public String toString() {
+        return getErasedSignature(new StringBuilder()).toString();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return (o == this);
+    }
+
+    private <T> T _unsupported() {
+        throw new UnsupportedOperationException("Operation should not be attempted on "+getClass().getName());
+    }
+}

src/main/java/com/fasterxml/jackson/databind/type/ReferenceType.java

@@ -25,7 +25,7 @@ public class ReferenceType extends SimpleType
      * @since 2.8
      */
     protected final JavaType _anchorType;
-    
+
     protected ReferenceType(Class<?> cls, TypeBindings bindings,
             JavaType superClass, JavaType[] superInts, JavaType refType,
             JavaType anchorType,

src/main/java/com/fasterxml/jackson/databind/type/SimpleType.java

@@ -211,7 +211,7 @@ public JavaType refine(Class<?> rawType, TypeBindings bindings,
         // SimpleType means something not-specialized, so:
         return null;
     }
-    
+
     @Override
     protected String buildCanonicalName()
     {

src/main/java/com/fasterxml/jackson/databind/type/TypeFactory.java

@@ -399,102 +399,94 @@ public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass)
                 newType = _fromClass(null, subclass, TypeBindings.emptyBindings());     
                 break;
             }
-
-            // If not, we'll need to do more thorough forward+backwards resolution. Sigh.
-
-            // 20-Oct-2015, tatu: Container, Map-types somewhat special. There is
-            //    a way to fully resolve and merge hierarchies; but that gets expensive
-            //    so let's, for now, try to create close-enough approximation that
-            //    is not 100% same, structurally, but has equivalent information for
-            //    our specific neeeds.
-            // 29-Mar-2016, tatu: See [databind#1173]  (and test `TypeResolverTest`)
-            //  for a case where this code does get invoked: not ideal
-            // 29-Jun-2016, tatu: As to bindings, this works for [databind#1215], but
-            //  not certain it would reliably work... but let's hope for best for now
+            // (4) If all else fails, do the full traversal using placeholders
             TypeBindings tb = _bindingsForSubtype(baseType, typeParamCount, subclass);
-            if (baseType.isInterface()) {
-                newType = baseType.refine(subclass, tb, null, new JavaType[] { baseType });
-            } else {
-                newType = baseType.refine(subclass, tb, baseType, NO_TYPES);
-            }
-            // Only SimpleType returns null, but if so just resolve regularly
-            if (newType == null) {
-                newType = _fromClass(null, subclass, tb);
-            }
+            newType = _fromClass(null, subclass, tb);
+
         } while (false);
 
         // 25-Sep-2016, tatu: As per [databind#1384] also need to ensure handlers get
         //   copied as well
         newType = newType.withHandlersFrom(baseType);
         return newType;
+    }
 
-        // 20-Oct-2015, tatu: Old simplistic approach
-
-        /*
-        // Currently mostly SimpleType instances can become something else
-        if (baseType instanceof SimpleType) {
-            // and only if subclass is an array, Collection or Map
-            if (subclass.isArray()
-                || Map.class.isAssignableFrom(subclass)
-                || Collection.class.isAssignableFrom(subclass)) {
-                // need to assert type compatibility...
-                if (!baseType.getRawClass().isAssignableFrom(subclass)) {
-                    throw new IllegalArgumentException("Class "+subclass.getClass().getName()+" not subtype of "+baseType);
-                }
-                // this _should_ work, right?
-                JavaType subtype = _fromClass(null, subclass, TypeBindings.emptyBindings());
-                // one more thing: handlers to copy?
-                Object h = baseType.getValueHandler();
-                if (h != null) {
-                    subtype = subtype.withValueHandler(h);
-                }
-                h = baseType.getTypeHandler();
-                if (h != null) {
-                    subtype = subtype.withTypeHandler(h);
-                }
-                return subtype;
-            }
+    private TypeBindings _bindingsForSubtype(JavaType baseType, int typeParamCount, Class<?> subclass)
+    {
+        PlaceholderForType[] placeholders = new PlaceholderForType[typeParamCount];
+        for (int i = 0; i < typeParamCount; ++i) {
+            placeholders[i] = new PlaceholderForType(i);
         }
-        // But there is the need for special case for arrays too, it seems
-        if (baseType instanceof ArrayType) {
-            if (subclass.isArray()) {
-                // actually see if it might be a no-op first:
-                ArrayType at = (ArrayType) baseType;
-                Class<?> rawComp = subclass.getComponentType();
-                if (at.getContentType().getRawClass() == rawComp) {
-                    return baseType;
-                }
-                JavaType componentType = _fromAny(null, rawComp, null);
-                return ((ArrayType) baseType).withComponentType(componentType);
-            }
+        TypeBindings b = TypeBindings.create(subclass, placeholders);
+        // First: pseudo-resolve to get placeholders in place:
+        JavaType tmpSub = _fromClass(null, subclass, b);
+        // Then find super-type
+        JavaType baseWithPlaceholders = tmpSub.findSuperType(baseType.getRawClass());
+        if (baseWithPlaceholders == null) { // should be found but...
+            throw new IllegalArgumentException(String.format(
+                    "Internal error: unable to locate supertype (%s) from resolved subtype %s", baseType.getRawClass().getName(),
+                    subclass.getName()));
+        }
+        // and traverse type hierarchies to both verify and to resolve placeholders
+        String error = _resolveTypePlaceholders(baseType, baseWithPlaceholders);
+        if (error != null) {
+            throw new IllegalArgumentException("Failed to specialize base type "+baseType.toCanonical()+" as "
+                    +subclass.getName()+", problem: "+error);
         }
 
-        // otherwise regular narrowing should work just fine
-        return baseType.narrowBy(subclass);
-        */
+        final JavaType[] typeParams = new JavaType[typeParamCount];
+        for (int i = 0; i < typeParamCount; ++i) {
+            JavaType t = placeholders[i].actualType();
+            // 18-Oct-2017, tatu: Looks like sometimes we have incomplete bindings (even if not
+            //     common, it is possible if subtype is type-erased class with added type
+            //     variable -- see test(s) with "bogus" type(s)).
+            if (t == null) {
+                t = unknownType();
+            }
+            typeParams[i] = t;
+        }
+        return TypeBindings.create(subclass, typeParams);
     }
 
-    private TypeBindings _bindingsForSubtype(JavaType baseType, int typeParamCount, Class<?> subclass)
+    private String _resolveTypePlaceholders(JavaType sourceType, JavaType actualType)
+        throws IllegalArgumentException
     {
-        // But otherwise gets bit tricky, as we need to partially resolve the type hierarchy
-        // (hopefully passing null Class for root is ok)
-        int baseCount = baseType.containedTypeCount();
-        if (baseCount == typeParamCount) {
-            if (typeParamCount == 1) {
-                return TypeBindings.create(subclass, baseType.containedType(0));
-            }
-            if (typeParamCount == 2) {
-                return TypeBindings.create(subclass, baseType.containedType(0),
-                        baseType.containedType(1));
+        List<JavaType> expectedTypes = sourceType.getBindings().getTypeParameters();
+        List<JavaType> actualTypes = actualType.getBindings().getTypeParameters();
+        for (int i = 0, len = expectedTypes.size(); i < len; ++i) {
+            JavaType exp = expectedTypes.get(i);
+            JavaType act = actualTypes.get(i);
+            if (!_verifyAndResolvePlaceholders(exp, act)) {
+                return String.format("Type parameter #%d/%d differs; can not specialize %s with %s",
+                        (i+1), len, exp.toCanonical(), act.toCanonical());
             }
-            List<JavaType> types = new ArrayList<JavaType>(baseCount);
-            for (int i = 0; i < baseCount; ++i) {
-                types.add(baseType.containedType(i));
+        }
+        return null;
+    }
+
+    private boolean _verifyAndResolvePlaceholders(JavaType exp, JavaType act)
+    {
+        // See if we have an actual type placeholder to resolve; if yes, replace
+        if (act instanceof PlaceholderForType) {
+            ((PlaceholderForType) act).actualType(exp);
+            return true;
+        }
+        // if not, try to verify compatibility. But note that we can not
+        // use simple equality as we need to resolve recursively
+        if (exp.getRawClass() != act.getRawClass()) {
+            return false;
+        }
+        // But we can check type parameters "blindly"
+        List<JavaType> expectedTypes = exp.getBindings().getTypeParameters();
+        List<JavaType> actualTypes = act.getBindings().getTypeParameters();
+        for (int i = 0, len = expectedTypes.size(); i < len; ++i) {
+            JavaType exp2 = expectedTypes.get(i);
+            JavaType act2 = actualTypes.get(i);
+            if (!_verifyAndResolvePlaceholders(exp2, act2)) {
+                return false;
             }
-            return TypeBindings.create(subclass, types);
         }
-        // Otherwise, two choices: match N first, or empty. Do latter, for now
-        return TypeBindings.emptyBindings();
+        return true;
     }
 
     /**
@@ -1394,13 +1386,12 @@ protected JavaType _fromParamType(ClassStack context, ParameterizedType ptype,
         // always of type Class: if not, need to add more code to resolve it to Class.        
         Type[] args = ptype.getActualTypeArguments();
         int paramCount = (args == null) ? 0 : args.length;
-        JavaType[] pt;
         TypeBindings newBindings;        
 
         if (paramCount == 0) {
             newBindings = EMPTY_BINDINGS;
         } else {
-            pt = new JavaType[paramCount];
+            JavaType[] pt = new JavaType[paramCount];
             for (int i = 0; i < paramCount; ++i) {
                 pt[i] = _fromAny(context, args[i], parentBindings);
             }

src/test/java/com/fasterxml/jackson/failing/NestedTypes1604Test.java → src/test/java/com/fasterxml/jackson/databind/type/NestedTypes1604Test.java

@@ -1,4 +1,4 @@
-package com.fasterxml.jackson.failing;
+package com.fasterxml.jackson.databind.type;
 
 import java.util.ArrayList;
 import java.util.List;