fix(core): Fix error on internal Administrator customFields (#3159)

packages/core/src/api/config/__snapshots__/graphql-custom-fields.spec.ts.snap

@@ -250,6 +250,15 @@ scalar JSON
 scalar DateTime"
 `;
 
+exports[`addGraphQLCustomFields() > uses JSON scalar in UpdateActiveAdministratorInput if only internal custom fields defined on Administrator 1`] = `
+"scalar JSON
+
+input UpdateActiveAdministratorInput {
+  placeholder: String
+  customFields: JSON
+}"
+`;
+
 exports[`addOrderLineCustomFieldsInput() > Modifies the schema when the addItemToOrder & adjustOrderLine mutation is present 1`] = `
 "type Mutation {
   addItemToOrder(id: ID!, quantity: Int!, customFields: OrderLineCustomFieldsInput = null): Boolean

packages/core/src/api/config/graphql-custom-fields.spec.ts

@@ -4,6 +4,7 @@ import { describe, expect, it } from 'vitest';
 import { CustomFieldConfig, CustomFields } from '../../config/custom-field/custom-field-types';
 
 import {
+    addActiveAdministratorCustomFields,
     addGraphQLCustomFields,
     addOrderLineCustomFieldsInput,
     addRegisterCustomerCustomFieldsInput,
@@ -23,6 +24,29 @@ describe('addGraphQLCustomFields()', () => {
         expect(printSchema(result)).toMatchSnapshot();
     });
 
+    // regression test for
+    // https://github.com/vendure-ecommerce/vendure/issues/3158
+    it('uses JSON scalar in UpdateActiveAdministratorInput if only internal custom fields defined on Administrator', () => {
+        // custom field that is internal but not readonly - should not cause
+        // `addActiveAdministratorCustomFields` to assume that
+        // `UpdateAdministratorCustomFieldsInput` exists
+        const customFieldConfig: Required<Pick<CustomFields, 'Administrator'>> = {
+            Administrator: [{ name: 'testField', type: 'string', internal: true }],
+        };
+        // `addActiveAdministratorCustomFields` should add customFields to
+        // UpdateActiveAdministratorInput as a JSON scalar. need to provide
+        // those types for that to work
+        const input = `
+            scalar JSON
+
+            input UpdateActiveAdministratorInput {
+                placeholder: String
+            }
+        `;
+        const schema = addActiveAdministratorCustomFields(input, customFieldConfig.Administrator);
+        expect(printSchema(schema)).toMatchSnapshot();
+    });
+
     it('extends a type', () => {
         const input = `
             type Product {

packages/core/src/api/config/graphql-custom-fields.ts

@@ -256,7 +256,7 @@ export function addServerConfigCustomFields(
     const customFieldTypeDefs = `
             """
             This type is deprecated in v2.2 in favor of the EntityCustomFields type,
-            which allows custom fields to be defined on user-supplies entities.
+            which allows custom fields to be defined on user-supplied entities.
             """
             type CustomFields {
                 ${Object.keys(customFieldConfig).reduce(
@@ -288,7 +288,9 @@ export function addActiveAdministratorCustomFields(
     administratorCustomFields: CustomFieldConfig[],
 ) {
     const schema = typeof typeDefsOrSchema === 'string' ? buildSchema(typeDefsOrSchema) : typeDefsOrSchema;
-    const writableCustomFields = administratorCustomFields?.filter(field => field.readonly !== true);
+    const writableCustomFields = administratorCustomFields?.filter(
+        field => field.readonly !== true && field.internal !== true,
+    );
     const extension = `
         extend input UpdateActiveAdministratorInput {
             customFields: ${