Fix misleading error when db.url is undefined

.changeset/better-errors-please.md

@@ -0,0 +1,5 @@
+---
+'@keystone-6/core': patch
+---
+
+Fixes misleading error when `db.url` is `undefined`

packages/core/src/artifacts.ts

@@ -187,6 +187,7 @@ export async function generateTypescriptTypesAndPrisma(
   if (dataProxy === true) {
     console.log('✨ Generating Prisma Client (data proxy)');
   }
+
   await Promise.all([
     generatePrismaClient(paths.schema.prisma, dataProxy),
     generateTypescriptTypes(cwd, config, graphQLSchema),

packages/core/src/lib/config.ts

@@ -92,11 +92,15 @@ function applyIdFieldDefaults(config: KeystoneConfig): KeystoneConfig['lists'] {
 
 export function initConfig(config: KeystoneConfig) {
   if (!['postgresql', 'sqlite', 'mysql'].includes(config.db.provider)) {
-    throw new Error(
+    throw new TypeError(
       'Invalid db configuration. Please specify db.provider as either "sqlite", "postgresql" or "mysql"'
     );
   }
 
+  // WARNING: Typescript should prevent this, but empty string is useful for Prisma errors
+  config.db.url ??= 'postgres://';
+
+  // TODO: use zod or something if want to follow this path
   return {
     ...config,
     lists: applyIdFieldDefaults(config),

packages/core/src/types/config/index.ts

@@ -140,22 +140,22 @@ type PrismaLogDefinition = {
 };
 
 export type DatabaseConfig<TypeInfo extends BaseKeystoneTypeInfo> = {
+  provider: DatabaseProvider;
   url: string;
+
   shadowDatabaseUrl?: string;
   onConnect?: (args: KeystoneContext<TypeInfo>) => Promise<void>;
-  /** @deprecated */
-  useMigrations?: boolean;
   enableLogging?: boolean | PrismaLogLevel | Array<PrismaLogLevel | PrismaLogDefinition>;
   idField?: IdFieldConfig;
-  provider: DatabaseProvider;
+  prismaClientPath?: string;
+  extendPrismaSchema?: (schema: string) => string;
 
+  /** @deprecated */
+  useMigrations?: boolean;
   /** @deprecated use extendPrismaSchema */
   prismaPreviewFeatures?: readonly string[]; // https://www.prisma.io/docs/concepts/components/preview-features
   /** @deprecated use extendPrismaSchema */
   additionalPrismaDatasourceProperties?: { [key: string]: string };
-
-  prismaClientPath?: string;
-  extendPrismaSchema?: (schema: string) => string;
 };
 
 // config.ui