Add assertion on specifiedBy in extendSchema test

Author: m14t

src/utilities/__tests__/extendSchema-test.js

@@ -345,13 +345,23 @@ describe('extendSchema', () => {
       }
 
       scalar Foo
+
+      directive @foo on SCALAR
     `);
     const extensionSDL = dedent`
-      extend scalar Foo @specified(by: "https://example.com/foo_spec")
+      extend scalar Foo @foo
+
+      extend scalar Foo @specified(by: "https://first.com/foo_spec")
+
+      extend scalar Foo @specified(by: "https://second.com/foo_spec")
     `;
+
     const extendedSchema = extendSchema(schema, parse(extensionSDL));
     const foo = extendedSchema.getType('Foo');
 
+    // Assert that the last specifiedBy takes precedence
+    expect(foo.toConfig().specifiedBy).to.equal('https://second.com/foo_spec');
+
     expect(validateSchema(extendedSchema)).to.deep.equal([]);
     expect(printExtensionNodes(foo)).to.deep.equal(extensionSDL);
   });

src/utilities/extendSchema.js

@@ -40,6 +40,7 @@ import {
   type EnumValueDefinitionNode,
   type DirectiveDefinitionNode,
   type ScalarTypeDefinitionNode,
+  type ScalarTypeExtensionNode,
 } from '../language/ast';
 
 import { assertValidSDLExtension } from '../validation/validate';
@@ -329,9 +330,14 @@ export function extendSchemaImpl(
   function extendScalarType(type: GraphQLScalarType): GraphQLScalarType {
     const config = type.toConfig();
     const extensions = typeExtensionsMap[config.name] || [];
+    const specifiedBys = [
+      config.specifiedBy,
+      ...extensions.map(getSpecifiedBy),
+    ].filter(Boolean);
 
     return new GraphQLScalarType({
       ...config,
+      specifiedBy: specifiedBys[specifiedBys.length - 1],
       extensionASTNodes: concatMaybeArrays(
         config.extensionASTNodes,
         extensions,
@@ -729,7 +735,9 @@ function getDeprecationReason(
 /**
  * Given a scalar node, returns the string value for the specified by.
  */
-function getSpecifiedBy(node: ScalarTypeDefinitionNode): ?string {
+function getSpecifiedBy(
+  node: ScalarTypeDefinitionNode | ScalarTypeExtensionNode,
+): ?string {
   const specified = getDirectiveValues(GraphQLSpecifiedDirective, node);
   return specified && (specified.by: any);
 }