Syncing: move global ID generation logic to an overridable method

Also make all resource syncing-related listener closures static.

Also correct return type for getGlobalIdentifierKey to string|int.
(We intentionally do not support returning null like many other
"get x key" methods would since such a case might break resource
syncing logic. This is also why we use inline getAttribute() in the
creating listener instead of calling the method.)

src/ResourceSyncing/Listeners/DeleteAllTenantMappings.php

@@ -9,30 +9,40 @@ use Stancl\Tenancy\Events\TenantDeleted;
 use Stancl\Tenancy\Listeners\QueueableListener;
 
 /**
- * Cleans up pivot records related to the deleted tenant.
- *
+ * Clean up pivot records related to the deleted tenant.
  * The listener only cleans up the pivot tables specified
  * in the $pivotTables property (see the property for details),
- * and is intended for use with tables that do not have tenant
- * foreign key constraints with onDelete('cascade').
+ * and is intended for use with tables that do not have tenant foreign key constraints.
+ *
+ * When using foreign key constraints, you'll still have to use ->onDelete('cascade')
+ * on the constraint (otherwise, deleting a tenant will throw a foreign key constraint violation).
+ * That way, the cleanup will happen on the database level, and this listener will essentially
+ * just perform an extra 'where' query.
  */
 class DeleteAllTenantMappings extends QueueableListener
 {
     /**
-     * Pivot tables to clean up after a tenant is deleted, in the
-     * ['table_name' => 'tenant_key_column'] format.
+     * Pivot tables to clean up after a tenant is deleted,
+     * formatted like ['table_name' => 'tenant_key_column'].
      *
      * Since we cannot automatically detect which pivot tables
-     * are being used, they have to be specified here manually.
+     * you want to clean up, they have to be specified here.
      *
-     * The default value follows the polymorphic table used by default.
+     * By default, resource syncing uses the tenant_resources table, and the records are associated
+     * to tenants by the tenant_id column (thus the ['tenant_resources' => 'tenant_id'] default).
+     *
+     * To customize this, set this property, e.g. in TenancyServiceProvider:
+     * DeleteAllTenantMappings::$pivotTables = [
+     *     'tenant_users' => 'tenant_id',
+     *     // You can also add more pivot tables here
+     * ];
      */
     public static array $pivotTables = ['tenant_resources' => 'tenant_id'];
 
     public function handle(TenantDeleted $event): void
     {
         foreach (static::$pivotTables as $table => $tenantKeyColumn) {
-            DB::table($table)->where($tenantKeyColumn, $event->tenant->getKey())->delete();
+            DB::table($table)->where($tenantKeyColumn, $event->tenant->getTenantKey())->delete();
         }
     }
 }

tests/ResourceSyncingTest.php

@@ -898,7 +898,7 @@ test('deleting SyncMaster automatically deletes its Syncables', function (bool $
     'basic pivot' => false,
 ]);
 
-test('tenant pivot records are deleted along with the tenants to which they belong', function (bool $dbLevelOnCascadeDelete, bool $morphPivot) {
+test('tenant pivot records are deleted along with the tenants to which they belong to', function (bool $dbLevelOnCascadeDelete, bool $morphPivot) {
     [$tenant] = createTenantsAndRunMigrations();
 
     if ($morphPivot) {