Custom directives are stripped during schema printting?

[dotansimha]

Trying to understand why my custom GraphQL directives are stripped when printSchema is executed (also using ``).

Found this line of code (isSpecDirective):

graphql-js/src/utilities/schemaPrinter.js

Lines 33 to 43 in 4f5e351

	export function printIntrospectionSchema(schema: GraphQLSchema): string {
	return printFilteredSchema(schema, isSpecDirective, isIntrospectionType);
	}
	function isSpecDirective(directiveName: string): boolean {
	return (
	directiveName === 'skip' ||
	directiveName === 'include' ||
	directiveName === 'deprecated'
	);
	}

Is there a reason for removing custom directives? I understand the @deprecated is a special directive and it effects more than just the docs, but I want to implement a custom directive such as skip or include - but the printer/introspection removes them.

[mrjj]

There were an answer on this:
#869

[leebyron]

@skip and @include cannot be added as custom directives - they will always be implemented using the built-in spec-compliant versions.

Other custom directives will be included. I've just added a test which confirms this