Restricting rules when an attachment file can actually be deleted (correctly handling exercise cloning and shared links).

Author: krulis-martin

app/V1Module/presenters/ExerciseFilesPresenter.php

@@ -345,7 +345,28 @@ public function actionDeleteAttachmentFile(string $id, string $fileId)
         $exercise->removeAttachmentFile($file);
         $this->exercises->flush();
 
-        $this->fileStorage->deleteAttachmentFile($file);
+        $this->attachmentFiles->refresh($file);
+        if ($file->getExercises()->isEmpty()) {
+            // file has no attachments to exercises, let's check the assignments
+            $isUsed = false;
+            foreach ($file->getAssignments() as $assignment) {
+                $group = $assignment->getGroup();
+                if ($group && !$group->isArchived()) {
+                    $isUsed = true;  // only non-archived assignments are considered relevant
+                    break;
+                }
+            }
+
+            if (!$isUsed) {
+                $this->fileStorage->deleteAttachmentFile($file);
+                if ($file->getAssignments()->isEmpty()) {
+                    // only if no attachments exists (at all)
+                    $file->detachAllConnections();  // remove lingering connections to deleted entities
+                    $this->attachmentFiles->flush($file);
+                    $this->attachmentFiles->remove($file);
+                }
+            }
+        }
 
         $this->sendSuccessResponse("OK");
     }

app/model/entity/AttachmentFile.php

@@ -49,6 +49,14 @@ function (Assignment $assignment) {
         );
     }
 
+    /**
+     * Remove all links to exercises and assignments (even to deleted ones).
+     */
+    public function detachAllConnections()
+    {
+        $this->exercises->clear();
+        $this->assignments->clear();
+    }
 
     /**
      * AttachmentFile constructor.