Preserve defaultValue literals

src/execution/getVariableSignature.ts

@@ -4,9 +4,12 @@ import type { VariableDefinitionNode } from '../language/ast.js';
 import { print } from '../language/printer.js';
 
 import { isInputType } from '../type/definition.js';
-import type { GraphQLInputType, GraphQLSchema } from '../type/index.js';
+import type {
+  GraphQLDefaultValueUsage,
+  GraphQLInputType,
+  GraphQLSchema,
+} from '../type/index.js';
 
-import { coerceInputLiteral } from '../utilities/coerceInputValue.js';
 import { typeFromAST } from '../utilities/typeFromAST.js';
 
 /**
@@ -18,7 +21,7 @@ import { typeFromAST } from '../utilities/typeFromAST.js';
 export interface GraphQLVariableSignature {
   name: string;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
 }
 
 export function getVariableSignature(
@@ -43,8 +46,6 @@ export function getVariableSignature(
   return {
     name: varName,
     type: varType,
-    defaultValue: defaultValue
-      ? coerceInputLiteral(varDefNode.defaultValue, varType)
-      : undefined,
+    defaultValue: defaultValue ? { literal: defaultValue } : undefined,
   };
 }

src/execution/values.ts

@@ -20,6 +20,7 @@ import type { GraphQLDirective } from '../type/directives.js';
 import type { GraphQLSchema } from '../type/schema.js';
 
 import {
+  coerceDefaultValue,
   coerceInputLiteral,
   coerceInputValue,
 } from '../utilities/coerceInputValue.js';
@@ -90,8 +91,11 @@ function coerceVariableValues(
 
     const { name: varName, type: varType } = varSignature;
     if (!Object.hasOwn(inputs, varName)) {
-      if (varDefNode.defaultValue) {
-        coercedValues[varName] = varSignature.defaultValue;
+      if (varSignature.defaultValue) {
+        coercedValues[varName] = coerceDefaultValue(
+          varSignature.defaultValue,
+          varType,
+        );
       } else if (isNonNullType(varType)) {
         const varTypeStr = inspect(varType);
         onError(
@@ -173,8 +177,11 @@ export function experimentalGetArgumentValues(
     const argumentNode = argNodeMap.get(name);
 
     if (argumentNode == null) {
-      if (argDef.defaultValue !== undefined) {
-        coercedValues[name] = argDef.defaultValue;
+      if (argDef.defaultValue) {
+        coercedValues[name] = coerceDefaultValue(
+          argDef.defaultValue,
+          argDef.type,
+        );
       } else if (isNonNullType(argType)) {
         throw new GraphQLError(
           `Argument "${name}" of required type "${inspect(argType)}" ` +
@@ -197,8 +204,11 @@ export function experimentalGetArgumentValues(
         scopedVariableValues == null ||
         !Object.hasOwn(scopedVariableValues, variableName)
       ) {
-        if (argDef.defaultValue !== undefined) {
-          coercedValues[name] = argDef.defaultValue;
+        if (argDef.defaultValue) {
+          coercedValues[name] = coerceDefaultValue(
+            argDef.defaultValue,
+            argDef.type,
+          );
         } else if (isNonNullType(argType)) {
           throw new GraphQLError(
             `Argument "${name}" of required type "${inspect(argType)}" ` +

src/index.ts

@@ -199,6 +199,7 @@ export type {
   GraphQLScalarSerializer,
   GraphQLScalarValueParser,
   GraphQLScalarLiteralParser,
+  GraphQLDefaultValueUsage,
 } from './type/index.js';
 
 // Parse and operate on GraphQL language source files.

src/type/__tests__/definition-test.ts

@@ -4,6 +4,7 @@ import { describe, it } from 'mocha';
 import { identityFunc } from '../../jsutils/identityFunc.js';
 import { inspect } from '../../jsutils/inspect.js';
 
+import { Kind } from '../../language/kinds.js';
 import { parseValue } from '../../language/parser.js';
 
 import type { GraphQLNullableType, GraphQLType } from '../definition.js';
@@ -581,6 +582,63 @@ describe('Type System: Input Objects', () => {
       'not used anymore',
     );
   });
+
+  describe('Input Object fields may have default values', () => {
+    it('accepts an Input Object type with a default value', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: { type: ScalarType, defaultValue: 3 },
+        },
+      });
+      expect(inputObjType.getFields().f).to.deep.include({
+        name: 'f',
+        description: undefined,
+        type: ScalarType,
+        defaultValue: { value: 3 },
+        deprecationReason: undefined,
+        extensions: {},
+        astNode: undefined,
+      });
+    });
+
+    it('accepts an Input Object type with a default value literal', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: {
+            type: ScalarType,
+            defaultValueLiteral: { kind: Kind.INT, value: '3' },
+          },
+        },
+      });
+      expect(inputObjType.getFields().f).to.deep.include({
+        name: 'f',
+        description: undefined,
+        type: ScalarType,
+        defaultValue: { literal: { kind: 'IntValue', value: '3' } },
+        deprecationReason: undefined,
+        extensions: {},
+        astNode: undefined,
+      });
+    });
+
+    it('rejects an Input Object type with potentially conflicting default values', () => {
+      const inputObjType = new GraphQLInputObjectType({
+        name: 'SomeInputObject',
+        fields: {
+          f: {
+            type: ScalarType,
+            defaultValue: 3,
+            defaultValueLiteral: { kind: Kind.INT, value: '3' },
+          },
+        },
+      });
+      expect(() => inputObjType.getFields()).to.throw(
+        'Argument "f" has both a defaultValue and a defaultValueLiteral property, but only one must be provided.',
+      );
+    });
+  });
 });
 
 describe('Type System: List', () => {

src/type/__tests__/predicate-test.ts

@@ -574,7 +574,10 @@ describe('Type predicates', () => {
         name: 'someArg',
         type: config.type,
         description: undefined,
-        defaultValue: config.defaultValue,
+        defaultValue:
+          config.defaultValue !== undefined
+            ? { value: config.defaultValue }
+            : undefined,
         deprecationReason: null,
         extensions: Object.create(null),
         astNode: undefined,
@@ -622,7 +625,10 @@ describe('Type predicates', () => {
         name: 'someInputField',
         type: config.type,
         description: undefined,
-        defaultValue: config.defaultValue,
+        defaultValue:
+          config.defaultValue !== undefined
+            ? { value: config.defaultValue }
+            : undefined,
         deprecationReason: null,
         extensions: Object.create(null),
         astNode: undefined,

src/type/definition.ts

@@ -16,6 +16,7 @@ import { toObjMap } from '../jsutils/toObjMap.js';
 import { GraphQLError } from '../error/GraphQLError.js';
 
 import type {
+  ConstValueNode,
   EnumTypeDefinitionNode,
   EnumTypeExtensionNode,
   EnumValueDefinitionNode,
@@ -799,7 +800,7 @@ export function defineArguments(
     name: assertName(argName),
     description: argConfig.description,
     type: argConfig.type,
-    defaultValue: argConfig.defaultValue,
+    defaultValue: defineDefaultValue(argName, argConfig),
     deprecationReason: argConfig.deprecationReason,
     extensions: toObjMap(argConfig.extensions),
     astNode: argConfig.astNode,
@@ -833,7 +834,8 @@ export function argsToArgsConfig(
     (arg) => ({
       description: arg.description,
       type: arg.type,
-      defaultValue: arg.defaultValue,
+      defaultValue: arg.defaultValue?.value,
+      defaultValueLiteral: arg.defaultValue?.literal,
       deprecationReason: arg.deprecationReason,
       extensions: arg.extensions,
       astNode: arg.astNode,
@@ -946,6 +948,7 @@ export interface GraphQLArgumentConfig {
   description?: Maybe<string>;
   type: GraphQLInputType;
   defaultValue?: unknown;
+  defaultValueLiteral?: ConstValueNode | undefined;
   deprecationReason?: Maybe<string>;
   extensions?: Maybe<Readonly<GraphQLArgumentExtensions>>;
   astNode?: Maybe<InputValueDefinitionNode>;
@@ -971,7 +974,7 @@ export interface GraphQLArgument {
   name: string;
   description: Maybe<string>;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
   deprecationReason: Maybe<string>;
   extensions: Readonly<GraphQLArgumentExtensions>;
   astNode: Maybe<InputValueDefinitionNode>;
@@ -985,6 +988,26 @@ export type GraphQLFieldMap<TSource, TContext> = ObjMap<
   GraphQLField<TSource, TContext>
 >;
 
+export type GraphQLDefaultValueUsage =
+  | { value: unknown; literal?: never }
+  | { literal: ConstValueNode; value?: never };
+
+export function defineDefaultValue(
+  argName: string,
+  config: GraphQLArgumentConfig | GraphQLInputFieldConfig,
+): GraphQLDefaultValueUsage | undefined {
+  if (config.defaultValue === undefined && !config.defaultValueLiteral) {
+    return;
+  }
+  devAssert(
+    !(config.defaultValue !== undefined && config.defaultValueLiteral),
+    `Argument "${argName}" has both a defaultValue and a defaultValueLiteral property, but only one must be provided.`,
+  );
+  return config.defaultValueLiteral
+    ? { literal: config.defaultValueLiteral }
+    : { value: config.defaultValue };
+}
+
 /**
  * Custom extensions
  *
@@ -1538,7 +1561,8 @@ export class GraphQLInputObjectType {
     const fields = mapValue(this.getFields(), (field) => ({
       description: field.description,
       type: field.type,
-      defaultValue: field.defaultValue,
+      defaultValue: field.defaultValue?.value,
+      defaultValueLiteral: field.defaultValue?.literal,
       deprecationReason: field.deprecationReason,
       extensions: field.extensions,
       astNode: field.astNode,
@@ -1572,7 +1596,7 @@ function defineInputFieldMap(
     name: assertName(fieldName),
     description: fieldConfig.description,
     type: fieldConfig.type,
-    defaultValue: fieldConfig.defaultValue,
+    defaultValue: defineDefaultValue(fieldName, fieldConfig),
     deprecationReason: fieldConfig.deprecationReason,
     extensions: toObjMap(fieldConfig.extensions),
     astNode: fieldConfig.astNode,
@@ -1613,6 +1637,7 @@ export interface GraphQLInputFieldConfig {
   description?: Maybe<string>;
   type: GraphQLInputType;
   defaultValue?: unknown;
+  defaultValueLiteral?: ConstValueNode | undefined;
   deprecationReason?: Maybe<string>;
   extensions?: Maybe<Readonly<GraphQLInputFieldExtensions>>;
   astNode?: Maybe<InputValueDefinitionNode>;
@@ -1624,7 +1649,7 @@ export interface GraphQLInputField {
   name: string;
   description: Maybe<string>;
   type: GraphQLInputType;
-  defaultValue: unknown;
+  defaultValue: GraphQLDefaultValueUsage | undefined;
   deprecationReason: Maybe<string>;
   extensions: Readonly<GraphQLInputFieldExtensions>;
   astNode: Maybe<InputValueDefinitionNode>;

src/type/index.ts

@@ -119,6 +119,7 @@ export type {
   GraphQLScalarSerializer,
   GraphQLScalarValueParser,
   GraphQLScalarLiteralParser,
+  GraphQLDefaultValueUsage,
 } from './definition.js';
 
 export {

src/type/introspection.ts

@@ -407,8 +407,13 @@ export const __InputValue: GraphQLObjectType = new GraphQLObjectType({
           'A GraphQL-formatted string representing the default value for this input value.',
         resolve(inputValue) {
           const { type, defaultValue } = inputValue;
-          const valueAST = astFromValue(defaultValue, type);
-          return valueAST ? print(valueAST) : null;
+          if (!defaultValue) {
+            return null;
+          }
+          const literal =
+            defaultValue.literal ?? astFromValue(defaultValue.value, type);
+          invariant(literal != null, 'Invalid default value');
+          return print(literal);
         },
       },
       isDeprecated: {

src/utilities/TypeInfo.ts

@@ -14,6 +14,7 @@ import { getEnterLeaveForKind } from '../language/visitor.js';
 import type {
   GraphQLArgument,
   GraphQLCompositeType,
+  GraphQLDefaultValueUsage,
   GraphQLEnumValue,
   GraphQLField,
   GraphQLInputField,
@@ -53,7 +54,7 @@ export class TypeInfo {
   private _parentTypeStack: Array<Maybe<GraphQLCompositeType>>;
   private _inputTypeStack: Array<Maybe<GraphQLInputType>>;
   private _fieldDefStack: Array<Maybe<GraphQLField<unknown, unknown>>>;
-  private _defaultValueStack: Array<Maybe<unknown>>;
+  private _defaultValueStack: Array<GraphQLDefaultValueUsage | undefined>;
   private _directive: Maybe<GraphQLDirective>;
   private _argument: Maybe<GraphQLArgument>;
   private _enumValue: Maybe<GraphQLEnumValue>;
@@ -124,7 +125,7 @@ export class TypeInfo {
     return this._fieldDefStack.at(-1);
   }
 
-  getDefaultValue(): Maybe<unknown> {
+  getDefaultValue(): GraphQLDefaultValueUsage | undefined {
     return this._defaultValueStack.at(-1);
   }
 

src/utilities/__tests__/buildClientSchema-test.ts

@@ -439,6 +439,7 @@ describe('Type System: build schema from introspection', () => {
       }
 
       type Query {
+        defaultID(intArg: ID = "123"): String
         defaultInt(intArg: Int = 30): String
         defaultList(listArg: [Int] = [1, 2, 3]): String
         defaultObject(objArg: Geo = { lat: 37.485, lon: -122.148 }): String
@@ -609,6 +610,28 @@ describe('Type System: build schema from introspection', () => {
     expect(result.data).to.deep.equal({ foo: 'bar' });
   });
 
+  it('can use client schema for execution if resolvers are added', () => {
+    const schema = buildSchema(`
+      type Query {
+        foo(bar: String = "abc"): String
+      }
+    `);
+
+    const introspection = introspectionFromSchema(schema);
+    const clientSchema = buildClientSchema(introspection);
+
+    const QueryType: GraphQLObjectType = clientSchema.getType('Query') as any;
+    QueryType.getFields().foo.resolve = (_value, args) => args.bar;
+
+    const result = graphqlSync({
+      schema: clientSchema,
+      source: '{ foo }',
+    });
+
+    expect(result.data).to.deep.equal({ foo: 'abc' });
+    expect(result.data).to.deep.equal({ foo: 'abc' });
+  });
+
   it('can build invalid schema', () => {
     const schema = buildSchema('type Query', { assumeValid: true });