$table->enum('type', ...)->change(); fails with Postgres

The issue here is that Laravel's $table->enum(...)->change() is not fully supported on PostgreSQL. Unlike MySQL, PostgreSQL does not have a native ENUM type in Laravel migrations—Laravel emulates it using a VARCHAR column with a CHECK constraint. However, Laravel's schema builder does not handle updating the CHECK constraint when you use ->change() on an enum column. This results in the syntax error you see.

How to fix it:

You need to manually drop the old check constraint and add a new one with the updated values. Here’s how you can do it in a migration:

1. Find the name of the existing check constraint.
   By default, Laravel does not name the check constraint, so PostgreSQL gives it an auto-generated name (e.g., customers_type_check). You can find it with:

   SELECT conname
   FROM pg_constraint
   WHERE conrelid = 'customers'::regclass AND contype = 'c';
   

2. Write a raw migration to drop and recreate the constraint.

   use Illuminate\Database\Migrations\Migration;
   use Illuminate\Support\Facades\DB;
   
   class UpdateCustomerTypeEnum extends Migration
   {
       public function up()
       {
           // Drop the old check constraint
           DB::statement('ALTER TABLE customers DROP CONSTRAINT IF EXISTS customers_type_check');
   
           // Add the new check constraint with the updated enum values
           DB::statement("ALTER TABLE customers ADD CONSTRAINT customers_type_check CHECK (type IN ('value1', 'value2', 'new_value', ...))");
       }
   
       public function down()
       {
           // Rollback: drop the new constraint and add the old one back
           DB::statement('ALTER TABLE customers DROP CONSTRAINT IF EXISTS customers_type_check');
           DB::statement("ALTER TABLE customers ADD CONSTRAINT customers_type_check CHECK (type IN ('value1', 'value2', ...))");
       }
   }
   

   Replace 'value1', 'value2', 'new_value', ... with your actual enum values.

Note:

• If you use a custom constraint name, adjust accordingly.
• If you want to automate the enum values, you can use implode on your enum class values.

Summary:
Laravel's enum(...)->change() does not work on PostgreSQL because it cannot update the CHECK constraint. You need to manually drop and recreate the constraint using raw SQL in your migration.