Fix index down migration (#172)

* Fix index down migration #160

* Apply fixes from StyleCI

Co-authored-by: StyleCI Bot <[email protected]>

migrations/2021_01_13_000000_unified_index_index.php

@@ -11,6 +11,7 @@
 
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Schema\Builder;
+use Illuminate\Support\Arr;
 
 return [
     'up' => function (Builder $schema) {
@@ -19,7 +20,19 @@
         });
     },
     'down' => function (Builder $schema) {
-        $schema->table('users', function (Blueprint $table) {
+        $schema->table('users', function (Blueprint $table) use ($schema) {
+            $connection = $schema->getConnection();
+            $schemaManager = $connection->getDoctrineSchemaManager();
+            $existingIndexes = $schemaManager->listTableIndexes($table->getTable());
+
+            // If migration 2021_04_21_000000_drop_users_unified_index_column has been applied, this index already no longer exists
+            // Unfortunately we can't call the protected createIndexName method so we have to build the index name manually
+            $indexName = strtolower(str_replace(['-', '.'], '_', $connection->getTablePrefix().$table->getTable()).'_unified_index_with_byobu_index');
+
+            if (!Arr::exists($existingIndexes, $indexName)) {
+                return;
+            }
+
             // Use array syntax so the blueprint "guesses" the full index name
             $table->dropIndex(['unified_index_with_byobu']);
         });