Improve errors when receiving bad introspection data (graphql#1063)

I've seen a few examples of passing bad introspection data to buildClientSchema() result in a hard to understand internal error. This instead prints a more understandable error which includes a print out of the bad value in question. Hopefully this aids debugging. This also adds a comment to the description of this function recommending that the "errors" field of a server response be checked before continuing to avoid partial results.

Author: leebyron

src/utilities/__tests__/buildClientSchema-test.js

@@ -736,9 +736,8 @@ describe('Type System: build schema from introspection', () => {
  expect(
  () => buildClientSchema(incompleteIntrospection)
  ).to.throw(
- 'Invalid or incomplete schema, unknown kind: undefined. Ensure ' +
- 'that a full introspection query is used in order to build a ' +
- 'client schema.'
+ 'Invalid or incomplete introspection result. Ensure that a full ' +
+ 'introspection query is used in order to build a client schema'
  );
  });
 

src/utilities/buildClientSchema.js

@@ -80,6 +80,9 @@ import type {
  * tools, but cannot be used to execute a query, as introspection does not
  * represent the "resolver", "parse" or "serialize" functions or any other
  * server-internal mechanisms.
+ *
+ * This function expects a complete introspection result. Don't forget to check
+ * the "errors" field of a server response before calling this function.
  */
 export function buildClientSchema(
  introspection: IntrospectionQuery
@@ -135,6 +138,9 @@ export function buildClientSchema(
  );
  return new GraphQLNonNull(nullableType);
  }
+ if (!typeRef.name) {
+ throw new Error('Unknown type reference: ' + JSON.stringify(typeRef));
+ }
  return getNamedType(typeRef.name);
  }
 
@@ -193,30 +199,30 @@ export function buildClientSchema(
  return type;
  }
 
-
  // Given a type's introspection result, construct the correct
  // GraphQLType instance.
  function buildType(type: IntrospectionType): GraphQLNamedType {
- switch (type.kind) {
- case TypeKind.SCALAR:
- return buildScalarDef(type);
- case TypeKind.OBJECT:
- return buildObjectDef(type);
- case TypeKind.INTERFACE:
- return buildInterfaceDef(type);
- case TypeKind.UNION:
- return buildUnionDef(type);
- case TypeKind.ENUM:
- return buildEnumDef(type);
- case TypeKind.INPUT_OBJECT:
- return buildInputObjectDef(type);
- default:
- throw new Error(
- `Invalid or incomplete schema, unknown kind: ${type.kind}. Ensure ` +
- 'that a full introspection query is used in order to build a ' +
- 'client schema.'
- );
+ if (type && type.name && type.kind) {
+ switch (type.kind) {
+ case TypeKind.SCALAR:
+ return buildScalarDef(type);
+ case TypeKind.OBJECT:
+ return buildObjectDef(type);
+ case TypeKind.INTERFACE:
+ return buildInterfaceDef(type);
+ case TypeKind.UNION:
+ return buildUnionDef(type);
+ case TypeKind.ENUM:
+ return buildEnumDef(type);
+ case TypeKind.INPUT_OBJECT:
+ return buildInputObjectDef(type);
+ }
  }
+ throw new Error(
+ 'Invalid or incomplete introspection result. Ensure that a full ' +
+ 'introspection query is used in order to build a client schema:' +
+ JSON.stringify(type)
+ );
  }
 
  function buildScalarDef(
@@ -238,6 +244,12 @@ export function buildClientSchema(
  function buildObjectDef(
  objectIntrospection: IntrospectionObjectType
  ): GraphQLObjectType {
+ if (!objectIntrospection.interfaces) {
+ throw new Error(
+ 'Introspection result missing interfaces: ' +
+ JSON.stringify(objectIntrospection)
+ );
+ }
  return new GraphQLObjectType({
  name: objectIntrospection.name,
  description: objectIntrospection.description,
@@ -260,6 +272,12 @@ export function buildClientSchema(
  function buildUnionDef(
  unionIntrospection: IntrospectionUnionType
  ): GraphQLUnionType {
+ if (!unionIntrospection.possibleTypes) {
+ throw new Error(
+ 'Introspection result missing possibleTypes: ' +
+ JSON.stringify(unionIntrospection)
+ );
+ }
  return new GraphQLUnionType({
  name: unionIntrospection.name,
  description: unionIntrospection.description,
@@ -271,6 +289,12 @@ export function buildClientSchema(
  function buildEnumDef(
  enumIntrospection: IntrospectionEnumType
  ): GraphQLEnumType {
+ if (!enumIntrospection.enumValues) {
+ throw new Error(
+ 'Introspection result missing enumValues: ' +
+ JSON.stringify(enumIntrospection)
+ );
+ }
  return new GraphQLEnumType({
  name: enumIntrospection.name,
  description: enumIntrospection.description,
@@ -288,6 +312,12 @@ export function buildClientSchema(
  function buildInputObjectDef(
  inputObjectIntrospection: IntrospectionInputObjectType
  ): GraphQLInputObjectType {
+ if (!inputObjectIntrospection.inputFields) {
+ throw new Error(
+ 'Introspection result missing inputFields: ' +
+ JSON.stringify(inputObjectIntrospection)
+ );
+ }
  return new GraphQLInputObjectType({
  name: inputObjectIntrospection.name,
  description: inputObjectIntrospection.description,
@@ -296,15 +326,29 @@ export function buildClientSchema(
  }
 
  function buildFieldDefMap(typeIntrospection) {
+ if (!typeIntrospection.fields) {
+ throw new Error(
+ 'Introspection result missing fields: ' +
+ JSON.stringify(typeIntrospection)
+ );
+ }
  return keyValMap(
  typeIntrospection.fields,
  fieldIntrospection => fieldIntrospection.name,
- fieldIntrospection => ({
- description: fieldIntrospection.description,
- deprecationReason: fieldIntrospection.deprecationReason,
- type: getOutputType(fieldIntrospection.type),
- args: buildInputValueDefMap(fieldIntrospection.args),
- })
+ fieldIntrospection => {
+ if (!fieldIntrospection.args) {
+ throw new Error(
+ 'Introspection result missing field args: ' +
+ JSON.stringify(fieldIntrospection)
+ );
+ }
+ return {
+ description: fieldIntrospection.description,
+ deprecationReason: fieldIntrospection.deprecationReason,
+ type: getOutputType(fieldIntrospection.type),
+ args: buildInputValueDefMap(fieldIntrospection.args),
+ };
+ }
  );
  }
 
@@ -349,6 +393,12 @@ export function buildClientSchema(
  DirectiveLocation.INLINE_FRAGMENT,
  ]
  );
+ if (!directiveIntrospection.args) {
+ throw new Error(
+ 'Introspection result missing directive args: ' +
+ JSON.stringify(directiveIntrospection)
+ );
+ }
  return new GraphQLDirective({
  name: directiveIntrospection.name,
  description: directiveIntrospection.description,