ClassCastException: graphql.schema.GraphQLObjectType cannot be cast to graphql.schema.GraphQLInputType

We are using same schema for Query and Mutation. While generation of schema it gives below error,

Exception in thread "main" java.lang.ClassCastException: graphql.schema.GraphQLObjectType cannot be cast to graphql.schema.GraphQLInputType
	at graphql.schema.GraphQLArgument.replaceTypeReferences(GraphQLArgument.java:30)
	at graphql.schema.SchemaUtil.resolveTypeReferencesForFieldsContainer(SchemaUtil.java:153)
	at graphql.schema.SchemaUtil.replaceTypeReferences(SchemaUtil.java:141)
	at graphql.schema.GraphQLSchema$Builder.build(GraphQLSchema.java:110)
	at graphql.schema.GraphQLSchema$Builder.build(GraphQLSchema.java:104)
	at com.opshub.oim.graphql.common.GraphQLConstants.main(GraphQLConstants.java:107)

Here is the main program to reproduce the issue,

public static void main(final String[] args) {
		final GraphQLInputObjectType attributeListInputObjectType = GraphQLInputObjectType.newInputObject().name("attributes")
				.description("attribute")
				.field(GraphQLInputObjectField.newInputObjectField().type(GraphQLString).name("key").build())
				.field(GraphQLInputObjectField.newInputObjectField().type(GraphQLString).name("value").build()).build();

		final GraphQLObjectType attributeListObjectType = GraphQLObjectType.newObject().name("attributes").description("attribute")
				.field(newFieldDefinition().type(GraphQLString).name("key").build())
				.field(newFieldDefinition().type(GraphQLString).name("value").build()).build();

		final GraphQLObjectType systemForMutation = GraphQLObjectType.newObject().name("systems").description("systems")
				.field(newFieldDefinition().name("attributes").type(new GraphQLList(attributeListInputObjectType)).build())
				.field(newFieldDefinition().name("attributes1").type(attributeListObjectType).build())
				.field(newFieldDefinition().type(new GraphQLTypeReference("systems")).name("parentSystem").build())
				.build();

		final GraphQLObjectType systemForQuery = GraphQLObjectType.newObject().name("systems").description("systems")
				.field(newFieldDefinition().name("attributes").type(new GraphQLList(attributeListObjectType)).build())
				.field(newFieldDefinition().name("attributes1").type(attributeListObjectType).build())
				.field(newFieldDefinition().type(new GraphQLTypeReference("systems")).name("parentSystem").build())
				.build();

		final GraphQLFieldDefinition systemWithArgsForMutation = newFieldDefinition().name("systems").type(systemForMutation)
				.dataFetcher(new SystemDataFetcher())
				.argument(GraphQLArgument.newArgument().name("attributes").type(new GraphQLList(attributeListInputObjectType)).build())
				.argument(GraphQLArgument.newArgument().name("attributes1").type(attributeListInputObjectType).build()).build();

		final GraphQLFieldDefinition systemWithArgsForQuery = newFieldDefinition().name("systems").type(systemForQuery)
				.dataFetcher(new SystemDataFetcher())
				.argument(GraphQLArgument.newArgument().name("attributes").type(new GraphQLList(attributeListObjectType)).build())
				.argument(GraphQLArgument.newArgument().name("attributes1").type(attributeListInputObjectType).build()).build();
		final GraphQLObjectType queryType = GraphQLObjectType.newObject().name("query").field(systemWithArgsForQuery).build();
		final GraphQLObjectType mutation = GraphQLObjectType.newObject().name("mutation").field(systemWithArgsForMutation).build();

		final GraphQLSchema schema = GraphQLSchema.newSchema().query(queryType).mutation(mutation).build();

}

Looks like, GraphQL use internal schema caching for resolveTypeReference method.

I think, If we change SchemaUtil.java below line or condition with and then it should work,

 GraphQLType resolveTypeReference(GraphQLType type, Map<String, GraphQLType> typeMap)
	/*     */ {
		/* 165 */ if ((type instanceof GraphQLTypeReference) **||** (typeMap.containsKey(type.getName()))) {

Regards, OpsHub Inc.

[danielocampo2]

@andimarek but does this limitation applies to any object in your schema? If we have 2 different queries with a parameter, say, “userID” then that means that we can’t use that same parameter name even if it represents exactly the same data for both queries? Thanks!

[andimarek]

@opshubdata As @bbakerman mentioned you can’t have to types with the same name: but you used attributes1 two times. We will improve the error message, but this will not fix your problem: you have to use unique type names.