Merging #1173, fixes tests

src/language/__tests__/schema-parser-test.js

@@ -712,7 +712,6 @@ type Hello {
         {
           kind: 'ScalarTypeDefinition',
           name: nameNode('Hello', { start: 7, end: 12 }),
-          type: null,
           directives: [],
           loc: { start: 0, end: 12 },
         },

src/language/ast.js

@@ -448,7 +448,7 @@ export type ScalarTypeDefinitionNode = {
   +loc?: Location,
   +description?: StringValueNode,
   +name: NameNode,
-  +type?: NamedTypeNode;
+  +type?: NamedTypeNode,
   +directives?: $ReadOnlyArray<DirectiveNode>,
 };
 

src/language/printer.js

@@ -110,9 +110,12 @@ const printDocASTReducer = {
 
   OperationTypeDefinition: ({ operation, type }) => operation + ': ' + type,
 
-  ScalarTypeDefinition: ({ description, name, directives }) =>
+  ScalarTypeDefinition: ({ description, name, type, directives }) =>
     join(
-      [description, join(['scalar', name, wrap(' as ', type), join(directives, ' ')], ' ')],
+      [
+        description,
+        join(['scalar', name, wrap('as ', type), join(directives, ' ')], ' '),
+      ],
       '\n',
     ),
 

src/type/__tests__/introspection-test.js

@@ -1310,7 +1310,7 @@ describe('Introspection', () => {
               description:
                 'Indicates this type is a scalar. ' +
                 '`ofType` may represent how this scalar is serialized.',
-              name: 'SCALAR'
+              name: 'SCALAR',
             },
             {
               description:

src/type/definition.js

@@ -461,18 +461,6 @@ export class GraphQLScalarType {
     this.astNode = config.astNode;
     this._scalarConfig = config;
     invariant(typeof config.name === 'string', 'Must provide name.');
-    if (this.ofType) {
-      const ofTypeName = this.ofType.name;
-      invariant(
-        ofTypeName === 'String' ||
-        ofTypeName === 'Int' ||
-        ofTypeName === 'Float' ||
-        ofTypeName === 'Boolean' ||
-        ofTypeName === 'ID',
-        `${this.name} may only be described in terms of a built-in scalar ` +
-        `type. However ${ofTypeName} is not a built-in scalar type.`
-      );
-    }
     invariant(
       typeof config.serialize === 'function',
       `${this.name} must provide "serialize" function. If this custom Scalar ` +
@@ -498,7 +486,8 @@ export class GraphQLScalarType {
 
   // Parses an externally provided value to use as an input.
   parseValue(value: mixed): mixed {
-    const parser = this._scalarConfig.parseValue || (this.ofType && this.ofType.parseValue);
+    const parser =
+      this._scalarConfig.parseValue || (this.ofType && this.ofType.parseValue);
     if (isInvalid(value)) {
       return undefined;
     }
@@ -507,7 +496,9 @@ export class GraphQLScalarType {
 
   // Parses an externally provided literal value to use as an input.
   parseLiteral(valueNode: ValueNode, variables: ?ObjMap<mixed>): mixed {
-    const parser = this._scalarConfig.parseLiteral || (this.ofType && this.ofType.parseLiteral);
+    const parser =
+      this._scalarConfig.parseLiteral ||
+      (this.ofType && this.ofType.parseLiteral);
     return parser
       ? parser(valueNode, variables)
       : valueFromASTUntyped(valueNode, variables);

src/type/introspection.js

@@ -207,7 +207,7 @@ export const __Type = new GraphQLObjectType({
     'The fundamental unit of any GraphQL Schema is the type. There are ' +
     'many kinds of types in GraphQL as represented by the `__TypeKind` enum.' +
     '\n\nDepending on the kind of a type, certain fields describe ' +
-    'information about that type. Scalar types provide a name, description' +
+    'information about that type. Scalar types provide a name, description ' +
     'and how they serialize, while Enum types provide their possible values. ' +
     'Object and Interface types provide the fields they describe. Abstract ' +
     'types, Union and Interface, provide the Object types possible ' +

src/type/validate.js

@@ -8,6 +8,7 @@
  */
 
 import {
+  isScalarType,
   isObjectType,
   isInterfaceType,
   isUnionType,
@@ -19,6 +20,7 @@ import {
   isOutputType,
 } from './definition';
 import type {
+  GraphQLScalarType,
   GraphQLObjectType,
   GraphQLInterfaceType,
   GraphQLUnionType,
@@ -28,6 +30,7 @@ import type {
 import { isDirective } from './directives';
 import type { GraphQLDirective } from './directives';
 import { isIntrospectionType } from './introspection';
+import { isSpecifiedScalarType } from './scalars';
 import { isSchema } from './schema';
 import type { GraphQLSchema } from './schema';
 import find from '../jsutils/find';
@@ -239,7 +242,10 @@ function validateTypes(context: SchemaValidationContext): void {
     // Ensure they are named correctly.
     validateName(context, type);
 
-    if (isObjectType(type)) {
+    if (isScalarType(type)) {
+      // Ensure Scalars can serialize as expected.
+      validateScalarSerialization(context, type);
+    } else if (isObjectType(type)) {
       // Ensure fields are valid
       validateFields(context, type);
 
@@ -261,6 +267,20 @@ function validateTypes(context: SchemaValidationContext): void {
   });
 }
 
+function validateScalarSerialization(
+  context: SchemaValidationContext,
+  scalarType: GraphQLScalarType,
+): void {
+  if (scalarType.ofType && !isSpecifiedScalarType(scalarType.ofType)) {
+    context.reportError(
+      `Scalar type ${scalarType.name} may only be described in terms of a ` +
+        `spec-defined scalar type. However ${String(scalarType.ofType)} is ` +
+        'not a built-in scalar type.',
+      scalarType.astNode && scalarType.astNode.type,
+    );
+  }
+}
+
 function validateFields(
   context: SchemaValidationContext,
   type: GraphQLObjectType | GraphQLInterfaceType,

src/utilities/__tests__/schemaPrinter-test.js

@@ -503,7 +503,7 @@ describe('Type System Printer', () => {
       ofType: GraphQLInt,
       serialize(value) {
         return value % 2 === 1 ? value : null;
-      }
+      },
     });
 
     const OddType = new GraphQLScalarType({
@@ -793,10 +793,10 @@ describe('Type System Printer', () => {
       types in GraphQL as represented by the \`__TypeKind\` enum.
 
       Depending on the kind of a type, certain fields describe information about that
-      type. Scalar types provide no information beyond a name and description, while
-      Enum types provide their values. Object and Interface types provide the fields
-      they describe. Abstract types, Union and Interface, provide the Object types
-      possible at runtime. List and NonNull types compose other types.
+      type. Scalar types provide a name, description and how they serialize, while
+      Enum types provide their possible values. Object and Interface types provide the
+      fields they describe. Abstract types, Union and Interface, provide the Object
+      types possible at runtime. List and NonNull types compose other types.
       """
       type __Type {
         kind: __TypeKind!
@@ -812,7 +812,9 @@ describe('Type System Printer', () => {
 
       """An enum describing what kind of type a given \`__Type\` is."""
       enum __TypeKind {
-        """Indicates this type is a scalar."""
+        """
+        Indicates this type is a scalar. \`ofType\` may represent how this scalar is serialized.
+        """
         SCALAR
 
         """
@@ -1013,8 +1015,8 @@ describe('Type System Printer', () => {
       # types in GraphQL as represented by the \`__TypeKind\` enum.
       #
       # Depending on the kind of a type, certain fields describe information about that
-      # type. Scalar types provide a name, descriptionand how they serialize, while Enum
-      # types provide their possible values. Object and Interface types provide the
+      # type. Scalar types provide a name, description and how they serialize, while
+      # Enum types provide their possible values. Object and Interface types provide the
       # fields they describe. Abstract types, Union and Interface, provide the Object
       # types possible at runtime. List and NonNull types compose other types.
       type __Type {

src/utilities/buildASTSchema.js

@@ -442,7 +442,10 @@ export class ASTDefinitionBuilder {
     return new GraphQLScalarType({
       name: def.name.value,
       description: getDescription(def, this._options),
-      ofType: def.type && this.buildType(def.type),
+      // Note: While this could make assertions to get the correctly typed
+      // values below, that would throw immediately while type system
+      // validation with validateSchema() will produce more actionable results.
+      ofType: def.type && (this.buildType(def.type): any),
       astNode: def,
       serialize: value => value,
     });

src/utilities/buildClientSchema.js

@@ -208,9 +208,9 @@ export function buildClientSchema(
   function buildScalarDef(
     scalarIntrospection: IntrospectionScalarType,
   ): GraphQLScalarType {
-    const ofType = scalarIntrospection.ofType ?
-      getType(scalarIntrospection.ofType) :
-      undefined;
+    const ofType = scalarIntrospection.ofType
+      ? (getType(scalarIntrospection.ofType): any)
+      : undefined;
     return new GraphQLScalarType({
       name: scalarIntrospection.name,
       description: scalarIntrospection.description,

src/utilities/findBreakingChanges.js

@@ -161,18 +161,16 @@ export function findTypesThatChangedKind(
           `${typeName} changed from ` +
           `${typeKindName(oldType)} to ${typeKindName(newType)}.`,
       });
-    } else if (
-      oldType instanceof GraphQLScalarType &&
-      newType instanceof GraphQLScalarType
-    ) {
+    } else if (isScalarType(oldType) && isScalarType(newType)) {
       const oldOfType = oldType.ofType;
       const newOfType = newType.ofType;
       if (oldOfType && newOfType && oldOfType !== newOfType) {
         breakingChanges.push({
           type: BreakingChangeType.TYPE_CHANGED_KIND,
-          description: `${typeName} changed from ` +
+          description:
+            `${typeName} changed from ` +
             `${typeKindName(oldType)} serialized as ${oldOfType.name} ` +
-            `to ${typeKindName(newType)} serialized as ${newOfType.name}.`
+            `to ${typeKindName(newType)} serialized as ${newOfType.name}.`,
         });
       }
     }