fix: gracefully handle migrations that cannot be reverted (#8087)

packages/core/utils/src/migrations/index.ts

@@ -15,6 +15,7 @@ export type MigrationsEvents = {
   migrated: [UmzugMigration]
   reverting: [UmzugMigration]
   reverted: [UmzugMigration]
+  "revert:skipped": [UmzugMigration & { reason: string }]
 }
 
 /**
@@ -105,6 +106,29 @@ export class Migrations extends EventEmitter<MigrationsEvents> {
 
     try {
       return await migrator.down(options)
+    } catch (error) {
+      /**
+       * This is a very ugly hack to recover from an exception thrown by
+       * MikrORM when the `down` method is not implemented by the
+       * migration.
+       *
+       * We cannot check if "down" method exists on the migration, because it
+       * always exists (as inherited from the parent class). Also, throwing
+       * an exception is important, so that Mikro ORM does not consider the
+       * given migration as reverted.
+       */
+      if (
+        error?.migration &&
+        error?.cause?.message === "This migration cannot be reverted"
+      ) {
+        this.emit("revert:skipped", {
+          ...error.migration,
+          reason: "Missing down method",
+        })
+        return []
+      }
+
+      throw error
     } finally {
       migrator["umzug"].clearListeners()
       await connection.close(true)

packages/core/utils/src/modules-sdk/migration-scripts/migration-down.ts

@@ -42,6 +42,9 @@ export function buildRevertMigrationScript({ moduleName, pathToMigrations }) {
     migrations.on("reverted", (migration) => {
       logger.info(`  ✔ Reverted ${migration.name}`)
     })
+    migrations.on("revert:skipped", (migration) => {
+      logger.info(`  ✔ Skipped ${migration.name}. ${migration.reason}`)
+    })
 
     try {
       const result = await migrations.revert()