Added user ownership migrate to delete screen.

app/Auth/UserRepo.php

@@ -1,6 +1,7 @@
 <?php namespace BookStack\Auth;
 
 use Activity;
+use BookStack\Entities\EntityProvider;
 use BookStack\Entities\Models\Book;
 use BookStack\Entities\Models\Bookshelf;
 use BookStack\Entities\Models\Chapter;
@@ -169,7 +170,7 @@ class UserRepo
      * Remove the given user from storage, Delete all related content.
      * @throws Exception
      */
-    public function destroy(User $user)
+    public function destroy(User $user, ?int $newOwnerId = null)
     {
         $user->socialAccounts()->delete();
         $user->apiTokens()->delete();
@@ -183,6 +184,25 @@ class UserRepo
         foreach ($profileImages as $image) {
             Images::destroy($image);
         }
+
+        if (!empty($newOwnerId)) {
+            $newOwner = User::query()->find($newOwnerId);
+            if (!is_null($newOwner)) {
+                $this->migrateOwnership($user, $newOwner);
+            }
+        }
+    }
+
+    /**
+     * Migrate ownership of items in the system from one user to another.
+     */
+    protected function migrateOwnership(User $fromUser, User $toUser)
+    {
+        $entities = (new EntityProvider)->all();
+        foreach ($entities as $instance) {
+            $instance->newQuery()->where('owned_by', '=', $fromUser->id)
+                ->update(['owned_by' => $toUser->id]);
+        }
     }
 
     /**

app/Entities/EntityProvider.php

@@ -55,7 +55,7 @@ class EntityProvider
     /**
      * Fetch all core entity types as an associated array
      * with their basic names as the keys.
-     * @return [string => Entity]
+     * @return array<Entity>
      */
     public function all(): array
     {

app/Http/Controllers/UserController.php

@@ -217,12 +217,13 @@ class UserController extends Controller
      * Remove the specified user from storage.
      * @throws \Exception
      */
-    public function destroy(int $id)
+    public function destroy(Request $request, int $id)
     {
         $this->preventAccessInDemoMode();
         $this->checkPermissionOrCurrentUser('users-manage', $id);
 
         $user = $this->userRepo->getById($id);
+        $newOwnerId = $request->get('new_owner_id', null);
 
         if ($this->userRepo->isOnlyAdmin($user)) {
             $this->showErrorNotification(trans('errors.users_cannot_delete_only_admin'));
@@ -234,7 +235,7 @@ class UserController extends Controller
             return redirect($user->getEditUrl());
         }
 
-        $this->userRepo->destroy($user);
+        $this->userRepo->destroy($user, $newOwnerId);
         $this->showSuccessNotification(trans('settings.users_delete_success'));
         $this->logActivity(ActivityType::USER_DELETE, $user);