Fixed #1581

Author: cowtowncoder

src/main/java/com/fasterxml/jackson/databind/introspect/AnnotationIntrospectorPair.java

@@ -781,10 +781,12 @@ public boolean hasAnySetterAnnotation(AnnotatedMethod am) {
     }
 
     protected boolean _isExplicitClassOrOb(Object maybeCls, Class<?> implicit) {
+        if ((maybeCls == null) || (maybeCls == implicit)) {
+            return false;
+        }
         if (maybeCls instanceof Class<?>) {
-            Class<?> cls = (Class<?>) maybeCls;
-            return (cls != implicit) && !ClassUtil.isBogusClass(cls);
+            return !ClassUtil.isBogusClass((Class<?>) maybeCls);
         }
-        return false;
+        return true;
     }
 }

src/test/java/com/fasterxml/jackson/databind/introspect/IntrospectorPairTest.java

@@ -10,8 +10,12 @@
 
 import com.fasterxml.jackson.databind.*;
 import com.fasterxml.jackson.databind.cfg.MapperConfig;
+import com.fasterxml.jackson.databind.deser.std.StringDeserializer;
+import com.fasterxml.jackson.databind.deser.std.UntypedObjectDeserializer;
 import com.fasterxml.jackson.databind.jsontype.NamedType;
 import com.fasterxml.jackson.databind.jsontype.TypeResolverBuilder;
+import com.fasterxml.jackson.databind.ser.std.StringSerializer;
+import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
 
 // started with [databind#1025] in mind
 @SuppressWarnings("serial")
@@ -45,12 +49,38 @@ public JsonInclude.Value findPropertyInclusion(Annotated a) {
         }
     }
 
+    static class IntrospectorWithHandlers extends AnnotationIntrospector {
+        final JsonDeserializer<?> _deserializer;
+        final JsonSerializer<?> _serializer;
+
+        public IntrospectorWithHandlers(JsonDeserializer<?> deser,
+                JsonSerializer<?> ser) {
+            _deserializer = deser;
+            _serializer = ser;
+        }
+
+        @Override
+        public Version version() {
+            return Version.unknownVersion();
+        }
+
+        @Override
+        public Object findDeserializer(Annotated am) {
+            return _deserializer;
+        }
+
+        @Override
+        public Object findSerializer(Annotated am) {
+            return _serializer;
+        }
+    }
+
     static class IntrospectorWithMap extends AnnotationIntrospector
     {
         private final Map<String, Object> values = new HashMap<>();
 
         private Version version = Version.unknownVersion();
-        
+
         public IntrospectorWithMap add(String key, Object value) {
             values.put(key, value);
             return this;
@@ -223,7 +253,7 @@ public void testAnnotationBundle() throws Exception
         assertFalse(new AnnotationIntrospectorPair(NO_ANNOTATIONS, NO_ANNOTATIONS)
                 .isAnnotationBundle(null));
     }
-    
+
     /*
     /**********************************************************
     /* Test methods, general class annotations
@@ -305,6 +335,48 @@ public void testFindClassDescription() throws Exception
 
     // // // 3 deprecated methods, skip
 
+    /*
+    /**********************************************************
+    /* Test methods, ser/deser
+    /**********************************************************
+     */
+
+    public void testFindSerializer() throws Exception
+    {
+        final JsonSerializer<?> serString = new StringSerializer();
+        final JsonSerializer<?> serToString = ToStringSerializer.instance;
+
+        AnnotationIntrospector intr1 = new IntrospectorWithHandlers(null, serString);
+        AnnotationIntrospector intr2 = new IntrospectorWithHandlers(null, serToString);
+        AnnotationIntrospector nop = AnnotationIntrospector.nopInstance();
+        
+        assertSame(serString,
+                new AnnotationIntrospectorPair(intr1, intr2).findSerializer(null));
+        assertSame(serToString,
+                new AnnotationIntrospectorPair(intr2, intr1).findSerializer(null));
+        // also: no-op instance should not block real one, regardless
+        assertSame(serString,
+                new AnnotationIntrospectorPair(nop, intr1).findSerializer(null));
+    }
+
+    public void testFindDeserializer() throws Exception
+    {
+        final JsonDeserializer<?> deserString = StringDeserializer.instance;
+        final JsonDeserializer<?> deserObject = UntypedObjectDeserializer.Vanilla.std;
+
+        AnnotationIntrospector intr1 = new IntrospectorWithHandlers(deserString, null);
+        AnnotationIntrospector intr2 = new IntrospectorWithHandlers(deserObject, null);
+        AnnotationIntrospector nop = AnnotationIntrospector.nopInstance();
+
+        assertSame(deserString,
+                new AnnotationIntrospectorPair(intr1, intr2).findDeserializer(null));
+        assertSame(deserObject,
+                new AnnotationIntrospectorPair(intr2, intr1).findDeserializer(null));
+        // also: no-op instance should not block real one, regardless
+        assertSame(deserString,
+                new AnnotationIntrospectorPair(nop, intr1).findDeserializer(null));
+    }
+
     /*
     /******************************************************
     /* Property auto-detection