Migration code breaks React Native Hermes bundle due to unsupported dynamic import

[bviebahn]

When using Kysely in an Expo / React Native project, even without using migrations, Hermes fails to bundle because the migration provider includes a computed dynamic import. Since this code is included in the main export bundle, it’s parsed even if unused.

❌ (/Users/expo/Library/Developer/Xcode/DerivedData/mobile-buyqshytqhqhjxgzhdwtlgltoake/Build/Intermediates.noindex/ArchiveIntermediates/mobile/BuildProductsPath/Release-iphoneos/main.jsbundle:298184:37) ...ield import(/* webpackIgnore: true */(0, _classPrivateFieldLooseBase2.default)(this, _props)[_props].path.join((0, _classPrivateFieldLooseBase2.default)(this, _props)[_props].migrationF... ^ Invalid expression encountered

This seems to be the same issue: #751

[cwqt]

Glad to know I'm not the only one with this! Here's a patch-package workaround in the meantime - it just stubs out the FileMigrationProvider so none of the code with dynamic imports are included in the bundle.

kysely+0.27.6.patch

diff --git a/node_modules/kysely/dist/cjs/migration/file-migration-provider.js b/node_modules/kysely/dist/cjs/migration/file-migration-provider.js
index 260b482..0352bc6 100644
--- a/node_modules/kysely/dist/cjs/migration/file-migration-provider.js
+++ b/node_modules/kysely/dist/cjs/migration/file-migration-provider.js
@@ -1,52 +1,20 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.FileMigrationProvider = void 0;
-const object_utils_js_1 = require("../util/object-utils.js");
+
 /**
- * Reads all migrations from a folder in node.js.
- *
- * ### Examples
- *
- * ```ts
- * import { promises as fs } from 'node:fs'
- * import path from 'node:path'
- *
- * new FileMigrationProvider({
- *   fs,
- *   path,
- *   migrationFolder: 'path/to/migrations/folder'
- * })
- * ```
+ * Stubbed FileMigrationProvider for React Native compatibility.
+ * Dynamic imports with path.join() are not supported in Metro bundler.
+ * Use a static migration provider instead.
  */
 class FileMigrationProvider {
-    #props;
     constructor(props) {
-        this.#props = props;
+        if (typeof __DEV__ !== 'undefined' && __DEV__) {
+            console.warn('FileMigrationProvider is stubbed out for React Native. Use a static migration provider instead.');
+        }
     }
     async getMigrations() {
-        const migrations = {};
-        const files = await this.#props.fs.readdir(this.#props.migrationFolder);
-        for (const fileName of files) {
-            if (fileName.endsWith('.js') ||
-                (fileName.endsWith('.ts') && !fileName.endsWith('.d.ts')) ||
-                fileName.endsWith('.mjs') ||
-                (fileName.endsWith('.mts') && !fileName.endsWith('.d.mts'))) {
-                const migration = await Promise.resolve(`${
-                /* webpackIgnore: true */ this.#props.path.join(this.#props.migrationFolder, fileName)}`).then(s => require(s));
-                const migrationKey = fileName.substring(0, fileName.lastIndexOf('.'));
-                // Handle esModuleInterop export's `default` prop...
-                if (isMigration(migration?.default)) {
-                    migrations[migrationKey] = migration.default;
-                }
-                else if (isMigration(migration)) {
-                    migrations[migrationKey] = migration;
-                }
-            }
-        }
-        return migrations;
+        return {};
     }
 }
 exports.FileMigrationProvider = FileMigrationProvider;
-function isMigration(obj) {
-    return (0, object_utils_js_1.isObject)(obj) && (0, object_utils_js_1.isFunction)(obj.up);
-}
diff --git a/node_modules/kysely/dist/esm/migration/file-migration-provider.js b/node_modules/kysely/dist/esm/migration/file-migration-provider.js
index f410a83..a7f83e4 100644
--- a/node_modules/kysely/dist/esm/migration/file-migration-provider.js
+++ b/node_modules/kysely/dist/esm/migration/file-migration-provider.js
@@ -1,49 +1,17 @@
 /// <reference types="./file-migration-provider.d.ts" />
-import { isFunction, isObject } from '../util/object-utils.js';
+
 /**
- * Reads all migrations from a folder in node.js.
- *
- * ### Examples
- *
- * ```ts
- * import { promises as fs } from 'node:fs'
- * import path from 'node:path'
- *
- * new FileMigrationProvider({
- *   fs,
- *   path,
- *   migrationFolder: 'path/to/migrations/folder'
- * })
- * ```
+ * Stubbed FileMigrationProvider for React Native compatibility.
+ * Dynamic imports with path.join() are not supported in Metro bundler.
+ * Use a static migration provider instead.
  */
 export class FileMigrationProvider {
-    #props;
     constructor(props) {
-        this.#props = props;
+        if (__DEV__) {
+            console.warn('FileMigrationProvider is stubbed out for React Native. Use a static migration provider instead.');
+        }
     }
     async getMigrations() {
-        const migrations = {};
-        const files = await this.#props.fs.readdir(this.#props.migrationFolder);
-        for (const fileName of files) {
-            if (fileName.endsWith('.js') ||
-                (fileName.endsWith('.ts') && !fileName.endsWith('.d.ts')) ||
-                fileName.endsWith('.mjs') ||
-                (fileName.endsWith('.mts') && !fileName.endsWith('.d.mts'))) {
-                const migration = await import(
-                /* webpackIgnore: true */ this.#props.path.join(this.#props.migrationFolder, fileName));
-                const migrationKey = fileName.substring(0, fileName.lastIndexOf('.'));
-                // Handle esModuleInterop export's `default` prop...
-                if (isMigration(migration?.default)) {
-                    migrations[migrationKey] = migration.default;
-                }
-                else if (isMigration(migration)) {
-                    migrations[migrationKey] = migration;
-                }
-            }
-        }
-        return migrations;
+        return {};
     }
 }
-function isMigration(obj) {
-    return isObject(obj) && isFunction(obj.up);
-}