Preserve sources of variable values

Depends on #3074

By way of introducing type `VariableValues`, allows `getVariableValues` to return both the coerced values as well as the original sources, which are then made available in `ExecutionContext`.

While variable sources are not used directly here, they're used directly in #3065. This PR is pulled out as a pre-req to aid review

Author: leebyron

src/execution/execute.d.ts

@@ -23,6 +23,8 @@ import {
   GraphQLObjectType,
 } from '../type/definition';
 
+import { VariableValues } from './values';
+
 /**
  * Terminology
  *
@@ -55,7 +57,7 @@ export interface ExecutionContext {
   contextValue: unknown;
   fragments: ObjMap<FragmentDefinitionNode>;
   operation: OperationDefinitionNode;
-  variableValues: { [key: string]: unknown };
+  variableValues: VariableValues;
   fieldResolver: GraphQLFieldResolver<any, any>;
   typeResolver: GraphQLTypeResolver<any, any>;
   errors: Array<GraphQLError>;

src/execution/execute.js

@@ -60,6 +60,7 @@ import {
 import { typeFromAST } from '../utilities/typeFromAST';
 import { getOperationRootType } from '../utilities/getOperationRootType';
 
+import type { VariableValues } from './values';
 import {
   getVariableValues,
   getArgumentValues,
@@ -98,7 +99,7 @@ export type ExecutionContext = {|
   rootValue: mixed,
   contextValue: mixed,
   operation: OperationDefinitionNode,
-  variableValues: { [variable: string]: mixed, ... },
+  variableValues: VariableValues,
   fieldResolver: GraphQLFieldResolver<any, any>,
   typeResolver: GraphQLTypeResolver<any, any>,
   errors: Array<GraphQLError>,
@@ -679,7 +680,7 @@ export function buildResolveInfo(
     fragments: exeContext.fragments,
     rootValue: exeContext.rootValue,
     operation: exeContext.operation,
-    variableValues: exeContext.variableValues,
+    variableValues: exeContext.variableValues.coerced,
   };
 }
 

src/execution/values.d.ts

@@ -1,5 +1,5 @@
 import { Maybe } from '../jsutils/Maybe';
-import { ObjMap } from '../jsutils/ObjMap';
+import { ReadOnlyObjMap } from '../jsutils/ObjMap';
 
 import { GraphQLError } from '../error/GraphQLError';
 import {
@@ -10,11 +10,20 @@ import {
 
 import { GraphQLDirective } from '../type/directives';
 import { GraphQLSchema } from '../type/schema';
-import { GraphQLField } from '../type/definition';
+import { GraphQLField, GraphQLInputType } from '../type/definition';
+
+export type VariableValues = {
+  readonly sources: ReadOnlyObjMap<{
+    readonly variable: VariableDefinitionNode;
+    readonly type: GraphQLInputType;
+    readonly value: unknown;
+  }>;
+  readonly coerced: ReadOnlyObjMap<unknown>;
+};
 
 type CoercedVariableValues =
   | { errors: ReadonlyArray<GraphQLError>; coerced?: never }
-  | { errors?: never; coerced: { [key: string]: unknown } };
+  | { errors?: never; coerced: VariableValues };
 
 /**
  * Prepares an object map of variableValues of the correct type based on the
@@ -43,7 +52,7 @@ export function getVariableValues(
 export function getArgumentValues(
   def: GraphQLField<unknown, unknown> | GraphQLDirective,
   node: FieldNode | DirectiveNode,
-  variableValues?: Maybe<ObjMap<unknown>>,
+  variableValues?: Maybe<VariableValues>,
 ): { [key: string]: unknown };
 
 /**
@@ -62,5 +71,5 @@ export function getDirectiveValues(
   node: {
     readonly directives?: ReadonlyArray<DirectiveNode>;
   },
-  variableValues?: Maybe<ObjMap<unknown>>,
+  variableValues?: Maybe<VariableValues>,
 ): undefined | { [key: string]: unknown };

src/execution/values.js

@@ -1,6 +1,6 @@
-import type { ObjMap } from '../jsutils/ObjMap';
-import { keyMap } from '../jsutils/keyMap';
+import type { ReadOnlyObjMap, ReadOnlyObjMapLike } from '../jsutils/ObjMap';
 import { inspect } from '../jsutils/inspect';
+import { keyMap } from '../jsutils/keyMap';
 import { printPathArray } from '../jsutils/printPathArray';
 
 import { GraphQLError } from '../error/GraphQLError';
@@ -14,7 +14,7 @@ import { Kind } from '../language/kinds';
 import { print } from '../language/printer';
 
 import type { GraphQLSchema } from '../type/schema';
-import type { GraphQLField } from '../type/definition';
+import type { GraphQLInputType, GraphQLField } from '../type/definition';
 import type { GraphQLDirective } from '../type/directives';
 import { isInputType, isNonNullType } from '../type/definition';
 
@@ -25,9 +25,18 @@ import {
   coerceDefaultValue,
 } from '../utilities/coerceInputValue';
 
+export type VariableValues = {|
+  +sources: ReadOnlyObjMap<{|
+    +variable: VariableDefinitionNode,
+    +type: GraphQLInputType,
+    +value: mixed,
+  |}>,
+  +coerced: ReadOnlyObjMap<mixed>,
+|};
+
 type CoercedVariableValues =
   | {| errors: $ReadOnlyArray<GraphQLError> |}
-  | {| coerced: { [variable: string]: mixed, ... } |};
+  | {| coerced: VariableValues |};
 
 /**
  * Prepares an object map of variableValues of the correct type based on the
@@ -43,7 +52,7 @@ type CoercedVariableValues =
 export function getVariableValues(
   schema: GraphQLSchema,
   varDefNodes: $ReadOnlyArray<VariableDefinitionNode>,
-  inputs: { +[variable: string]: mixed, ... },
+  inputs: ReadOnlyObjMapLike<mixed>,
   options?: {| maxErrors?: number |},
 ): CoercedVariableValues {
   const errors = [];
@@ -76,10 +85,11 @@ export function getVariableValues(
 function coerceVariableValues(
   schema: GraphQLSchema,
   varDefNodes: $ReadOnlyArray<VariableDefinitionNode>,
-  inputs: { +[variable: string]: mixed, ... },
+  inputs: ReadOnlyObjMapLike<mixed>,
   onError: (error: GraphQLError) => void,
-): { [variable: string]: mixed, ... } {
-  const coercedValues = {};
+): VariableValues {
+  const sources = Object.create(null);
+  const coerced = Object.create(null);
   for (const varDefNode of varDefNodes) {
     const varName = varDefNode.variable.name.value;
     const varType = typeFromAST(schema, varDefNode.type);
@@ -97,11 +107,14 @@ function coerceVariableValues(
     }
 
     if (!hasOwnProperty(inputs, varName)) {
-      if (varDefNode.defaultValue) {
-        coercedValues[varName] = coerceInputLiteral(
-          varDefNode.defaultValue,
-          varType,
-        );
+      const defaultValue = varDefNode.defaultValue;
+      if (defaultValue) {
+        sources[varName] = {
+          variable: varDefNode,
+          type: varType,
+          value: undefined,
+        };
+        coerced[varName] = coerceInputLiteral(defaultValue, varType);
       } else if (isNonNullType(varType)) {
         const varTypeStr = inspect(varType);
         onError(
@@ -126,7 +139,8 @@ function coerceVariableValues(
       continue;
     }
 
-    coercedValues[varName] = coerceInputValue(
+    sources[varName] = { variable: varDefNode, type: varType, value };
+    coerced[varName] = coerceInputValue(
       value,
       varType,
       (path, invalidValue, error) => {
@@ -149,7 +163,7 @@ function coerceVariableValues(
     );
   }
 
-  return coercedValues;
+  return { sources, coerced };
 }
 
 /**
@@ -165,7 +179,7 @@ function coerceVariableValues(
 export function getArgumentValues(
   def: GraphQLField<mixed, mixed> | GraphQLDirective,
   node: FieldNode | DirectiveNode,
-  variableValues?: ?ObjMap<mixed>,
+  variableValues?: ?VariableValues,
 ): { [argument: string]: mixed, ... } {
   const coercedValues = {};
 
@@ -201,7 +215,7 @@ export function getArgumentValues(
       const variableName = valueNode.name.value;
       if (
         variableValues == null ||
-        !hasOwnProperty(variableValues, variableName)
+        variableValues.coerced[variableName] === undefined
       ) {
         if (argDef.defaultValue) {
           coercedValues[name] = coerceDefaultValue(
@@ -217,7 +231,7 @@ export function getArgumentValues(
         }
         continue;
       }
-      isNull = variableValues[variableName] == null;
+      isNull = variableValues.coerced[variableName] == null;
     }
 
     if (isNull && isNonNullType(argType)) {
@@ -257,7 +271,7 @@ export function getArgumentValues(
 export function getDirectiveValues(
   directiveDef: GraphQLDirective,
   node: { +directives?: $ReadOnlyArray<DirectiveNode>, ... },
-  variableValues?: ?ObjMap<mixed>,
+  variableValues?: ?VariableValues,
 ): void | { [argument: string]: mixed, ... } {
   // istanbul ignore next (See: 'https://github.com/graphql/graphql-js/issues/2203')
   const directiveNode = node.directives?.find(

src/type/definition.d.ts

@@ -5,7 +5,7 @@ import { Maybe } from '../jsutils/Maybe';
 
 import { PromiseOrValue } from '../jsutils/PromiseOrValue';
 import { Path } from '../jsutils/Path';
-import { ObjMap } from '../jsutils/ObjMap';
+import { ObjMap, ReadOnlyObjMap } from '../jsutils/ObjMap';
 
 import {
   ScalarTypeDefinitionNode,
@@ -345,7 +345,7 @@ export type GraphQLScalarValueParser<TInternal> = (
 ) => Maybe<TInternal>;
 export type GraphQLScalarLiteralParser<TInternal> = (
   valueNode: ValueNode,
-  variables: Maybe<ObjMap<unknown>>,
+  variables: Maybe<ReadOnlyObjMap<unknown>>,
 ) => Maybe<TInternal>;
 
 export interface GraphQLScalarTypeConfig<TInternal, TExternal> {
@@ -487,7 +487,7 @@ export interface GraphQLResolveInfo {
   readonly fragments: ObjMap<FragmentDefinitionNode>;
   readonly rootValue: unknown;
   readonly operation: OperationDefinitionNode;
-  readonly variableValues: { [variableName: string]: unknown };
+  readonly variableValues: ReadOnlyObjMap<unknown>;
 }
 
 /**
@@ -789,7 +789,7 @@ export class GraphQLEnumType {
   parseValue(value: unknown): Maybe<any>;
   parseLiteral(
     valueNode: ValueNode,
-    _variables: Maybe<ObjMap<unknown>>,
+    _variables: Maybe<ReadOnlyObjMap<unknown>>,
   ): Maybe<any>;
 
   toConfig(): GraphQLEnumTypeConfig & {

src/type/definition.js

@@ -641,7 +641,7 @@ export type GraphQLScalarValueParser<TInternal> = (
 
 export type GraphQLScalarLiteralParser<TInternal> = (
   valueNode: ValueNode,
-  variables: ?ObjMap<mixed>,
+  variables: ?ReadOnlyObjMap<mixed>,
 ) => ?TInternal;
 
 export type GraphQLScalarTypeConfig<TInternal, TExternal> = {|
@@ -909,7 +909,7 @@ export type GraphQLResolveInfo = {|
   +fragments: ObjMap<FragmentDefinitionNode>,
   +rootValue: mixed,
   +operation: OperationDefinitionNode,
-  +variableValues: { [variable: string]: mixed, ... },
+  +variableValues: ReadOnlyObjMap<mixed>,
 |};
 
 export type GraphQLFieldConfig<
@@ -1351,7 +1351,10 @@ export class GraphQLEnumType /* <T> */ {
     return enumValue.value;
   }
 
-  parseLiteral(valueNode: ValueNode, _variables: ?ObjMap<mixed>): ?any /* T */ {
+  parseLiteral(
+    valueNode: ValueNode,
+    _variables: ?ReadOnlyObjMap<mixed>,
+  ): ?any /* T */ {
     // Note: variables will be resolved to a value before calling this function.
     if (valueNode.kind !== Kind.ENUM) {
       const valueStr = print(valueNode);