Add @specified directive

This in an implementation for a spec proposal:

* Spec proposal: [[RFC] Custom Scalar Specification URIs](graphql/graphql-spec#649)
* Original issue: [[RFC] Custom Scalar Specification URIs](graphql/graphql-spec#635)

Please let me know if I forgot something.

src/type/__tests__/introspection-test.js

@@ -847,6 +847,25 @@ describe('Introspection', () => {
                 },
               ],
             },
+            {
+              name: 'specified',
+              locations: ['FIELD_DEFINITION'],
+              args: [
+                {
+                  defaultValue: null,
+                  name: 'by',
+                  type: {
+                    kind: 'NON_NULL',
+                    name: null,
+                    ofType: {
+                      kind: 'SCALAR',
+                      name: 'String',
+                      ofType: null,
+                    },
+                  },
+                },
+              ],
+            },
             {
               name: 'deprecated',
               locations: ['FIELD_DEFINITION', 'ENUM_VALUE'],

src/type/directives.d.ts

@@ -54,6 +54,12 @@ export const GraphQLIncludeDirective: GraphQLDirective;
  */
 export const GraphQLSkipDirective: GraphQLDirective;
 
+/**
+ * Used to provide an RFC3986-compliant URI for specifying the behaviour of
+ * custom scalar definitions.
+ */
+export const GraphQLSpecifiedDirective: GraphQLDirective;
+
 /**
  * Constant string used for default reason for a deprecation.
  */

src/type/directives.js

@@ -167,6 +167,24 @@ export const GraphQLSkipDirective = new GraphQLDirective({
   },
 });
 
+/**
+ * Used to provide an RFC3986-compliant URI for specifying the behaviour of
+ * custom scalar definitions.
+ */
+export const GraphQLSpecifiedDirective = new GraphQLDirective({
+  name: 'specified',
+  description:
+    'Exposes a RFC3986-compliant URI that specifies the behaviour of this scalar.',
+  locations: [DirectiveLocation.FIELD_DEFINITION],
+  args: {
+    by: {
+      type: GraphQLNonNull(GraphQLString),
+      description:
+        'The RFC3986-compliant URI that specifies the behaviour of this scalar.',
+    },
+  },
+});
+
 /**
  * Constant string used for default reason for a deprecation.
  */
@@ -195,6 +213,7 @@ export const GraphQLDeprecatedDirective = new GraphQLDirective({
 export const specifiedDirectives = Object.freeze([
   GraphQLIncludeDirective,
   GraphQLSkipDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 ]);
 

src/utilities/__tests__/buildASTSchema-test.js

@@ -15,6 +15,7 @@ import {
   assertDirective,
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 } from '../../type/directives';
 import {
@@ -182,12 +183,15 @@ describe('Schema Builder', () => {
     expect(cycleSDL(sdl, { commentDescriptions: true })).to.equal(sdl);
   });
 
-  it('Maintains @skip & @include', () => {
+  it('Maintains @include, @skip & @specified', () => {
     const schema = buildSchema('type Query');
 
-    expect(schema.getDirectives()).to.have.lengthOf(3);
+    expect(schema.getDirectives()).to.have.lengthOf(4);
     expect(schema.getDirective('skip')).to.equal(GraphQLSkipDirective);
     expect(schema.getDirective('include')).to.equal(GraphQLIncludeDirective);
+    expect(schema.getDirective('specified')).to.equal(
+      GraphQLSpecifiedDirective,
+    );
     expect(schema.getDirective('deprecated')).to.equal(
       GraphQLDeprecatedDirective,
     );
@@ -197,27 +201,32 @@ describe('Schema Builder', () => {
     const schema = buildSchema(`
       directive @skip on FIELD
       directive @include on FIELD
+      directive @specified on FIELD_DEFINITION
       directive @deprecated on FIELD_DEFINITION
     `);
 
-    expect(schema.getDirectives()).to.have.lengthOf(3);
+    expect(schema.getDirectives()).to.have.lengthOf(4);
     expect(schema.getDirective('skip')).to.not.equal(GraphQLSkipDirective);
     expect(schema.getDirective('include')).to.not.equal(
       GraphQLIncludeDirective,
     );
+    expect(schema.getDirective('specified')).to.not.equal(
+      GraphQLSpecifiedDirective,
+    );
     expect(schema.getDirective('deprecated')).to.not.equal(
       GraphQLDeprecatedDirective,
     );
   });
 
-  it('Adding directives maintains @skip & @include', () => {
+  it('Adding directives maintains @include, @skip & @specified', () => {
     const schema = buildSchema(`
       directive @foo(arg: Int) on FIELD
     `);
 
-    expect(schema.getDirectives()).to.have.lengthOf(4);
+    expect(schema.getDirectives()).to.have.lengthOf(5);
     expect(schema.getDirective('skip')).to.not.equal(undefined);
     expect(schema.getDirective('include')).to.not.equal(undefined);
+    expect(schema.getDirective('specified')).to.not.equal(undefined);
     expect(schema.getDirective('deprecated')).to.not.equal(undefined);
   });
 

src/utilities/__tests__/findBreakingChanges-test.js

@@ -7,6 +7,7 @@ import { GraphQLSchema } from '../../type/schema';
 import {
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
+  GraphQLSpecifiedDirective,
   GraphQLDeprecatedDirective,
 } from '../../type/directives';
 
@@ -790,7 +791,11 @@ describe('findBreakingChanges', () => {
     const oldSchema = new GraphQLSchema({});
 
     const newSchema = new GraphQLSchema({
-      directives: [GraphQLSkipDirective, GraphQLIncludeDirective],
+      directives: [
+        GraphQLSkipDirective,
+        GraphQLIncludeDirective,
+        GraphQLSpecifiedDirective,
+      ],
     });
 
     expect(findBreakingChanges(oldSchema, newSchema)).to.deep.equal([

src/utilities/__tests__/schemaPrinter-test.js

@@ -590,6 +590,14 @@ describe('Type System Printer', () => {
         if: Boolean!
       ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
+      """
+      Exposes a RFC3986-compliant URI that specifies the behaviour of this scalar.
+      """
+      directive @specified(
+        """The RFC3986-compliant URI that specifies the behaviour of this scalar."""
+        by: String!
+      ) on FIELD_DEFINITION
+
       """Marks an element of a GraphQL schema as no longer supported."""
       directive @deprecated(
         """
@@ -803,6 +811,12 @@ describe('Type System Printer', () => {
         if: Boolean!
       ) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
+      # Exposes a RFC3986-compliant URI that specifies the behaviour of this scalar.
+      directive @specified(
+        # The RFC3986-compliant URI that specifies the behaviour of this scalar.
+        by: String!
+      ) on FIELD_DEFINITION
+
       # Marks an element of a GraphQL schema as no longer supported.
       directive @deprecated(
         # Explains why this element was deprecated, usually also including a suggestion for how to access supported similar data. Formatted using the Markdown syntax (as specified by [CommonMark](https://commonmark.org/).

src/utilities/buildASTSchema.js

@@ -55,6 +55,7 @@ import {
   GraphQLSkipDirective,
   GraphQLIncludeDirective,
   GraphQLDeprecatedDirective,
+  GraphQLSpecifiedDirective,
 } from '../type/directives';
 import {
   type GraphQLType,
@@ -170,6 +171,10 @@ export function buildASTSchema(
     directives.push(GraphQLIncludeDirective);
   }
 
+  if (!directives.some(directive => directive.name === 'specified')) {
+    directives.push(GraphQLSpecifiedDirective);
+  }
+
   if (!directives.some(directive => directive.name === 'deprecated')) {
     directives.push(GraphQLDeprecatedDirective);
   }