Add a test for handling of "unknown type id"

Author: cowtowncoder

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

@@ -889,7 +889,12 @@ public JavaType handleUnknownTypeId(JavaType baseType, String id,
                 if (type.hasRawClass(Void.class)) {
                     return null;
                 }
-                return type;
+                // But ensure there's type compatibility
+                if (type.isTypeOrSubTypeOf(baseType.getRawClass())) {
+                    return type;
+                }
+                throw unknownTypeException(baseType, id,
+                        "problem handler tried to resolve into non-subtype: "+type);
             }
             h = h.next();
         }

src/test/java/com/fasterxml/jackson/databind/filter/ProblemHandlerTest.java

@@ -0,0 +1,48 @@
+package com.fasterxml.jackson.databind.filter;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.deser.DeserializationProblemHandler;
+
+public class ProblemHandlerTest extends BaseMapTest
+{
+    static class TypeIdHandler
+        extends DeserializationProblemHandler
+    {
+        @Override
+        public JavaType handleUnknownTypeId(DeserializationContext ctxt,
+                JavaType baseType, String subTypeId,
+                String failureMsg)
+            throws IOException
+        {
+            return ctxt.constructType(Impl.class);
+        }
+    }
+
+    @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type")
+    static class Base { }
+    static class Impl extends Base {
+        public int a;
+    }
+
+    static class BaseWrapper {
+        public Base value;
+    }
+    
+    /*
+    /**********************************************************
+    /* Test methods
+    /**********************************************************
+     */
+
+    public void testInvalidTypeId() throws Exception
+    {
+        ObjectMapper mapper = new ObjectMapper()
+            .addHandler(new TypeIdHandler());
+        BaseWrapper w = mapper.readValue("{\"value\":{\"type\":\"foo\",\"a\":4}}",
+                BaseWrapper.class);
+        assertNotNull(w);
+    }
+}

src/test/java/com/fasterxml/jackson/databind/filter/TestUnknownPropertyDeserialization.java

@@ -42,7 +42,7 @@ public TestBean() { }
      * just marks unknown property/ies when encountered, along with
      * Json value of the property.
      */
-    final static class MyHandler
+    static class MyHandler
         extends DeserializationProblemHandler
     {
         @Override