fix: if name is null, fallback to class's simpleName

Author: kenzhang-mark43

modules/swagger-core/src/main/java/io/swagger/v3/core/jackson/ModelResolver.java

@@ -867,7 +867,7 @@ public Schema resolve(AnnotatedType annotatedType, ModelConverterContext context
             StringUtils.isNotBlank(model.getName()))
         {
             if (context.getDefinedModels().containsKey(model.getName())) {
-                model = new Schema().name(model.getName()).$ref(constructRef(model.getName()));
+                model = new Schema().$ref(constructRef(model.getName()));
             }
         } else if (model != null && model.get$ref() != null) {
             model = new Schema().$ref(StringUtils.isNotEmpty(model.get$ref()) ? model.get$ref() : model.getName());
@@ -1968,6 +1968,9 @@ protected Schema resolveWrapping(JavaType type, ModelConverterContext context, S
                 if (JsonTypeInfo.Id.CLASS.equals(id)) {
                     name = type.getRawClass().getName();
                 }
+                if(JsonTypeInfo.Id.NAME.equals(id) && name == null) {
+                    name = type.getRawClass().getSimpleName();
+                }
                 Schema wrapperSchema = new ObjectSchema();
                 wrapperSchema.name(model.getName());
                 wrapperSchema.addProperties(name, model);

modules/swagger-core/src/test/java/io/swagger/v3/core/resolving/Ticket2884Test.java

@@ -52,7 +52,11 @@ public void test2884() {
     @Test
     public void test2884_null() {
         ResolvedSchema schema = ModelConverters.getInstance().readAllAsResolvedSchema(new AnnotatedType(Ticket2884ModelClass.class).resolveAsRef(true));
-        Object o = schema.schema.getProperties().get(Ticket2884ModelClass.class.getSimpleName());
+        Schema o = (Schema)schema.schema.getProperties().get(Ticket2884ModelClass.class.getSimpleName());
         Assert.assertNotNull(o);
+        Assert.assertTrue(o.get$ref().contains(Ticket2884ModelClass.class.getSimpleName()));
+        SerializationMatchers.assertEqualsToYaml(schema.schema.getProperties(), "Ticket2884ModelClass:\n" +
+                "  $ref: '#/components/schemas/Ticket2884ModelClass'");
+
     }
 }