fix: remove orphaned grouper instances and add fallback for str()

Remove a grouper instance if the last Snippet instance connected to it gets deleted. Just in case also check for empty queryset in the name method of a grouper.

Author: Marius Schulze

src/djangocms_snippet/models.py

@@ -36,6 +36,9 @@ def __str__(self):
     @property
     def name(self):
         snippet_qs = Snippet.admin_manager.filter(snippet_grouper=self)
+        if not snippet_qs.exists():
+            empty_grouper = _("Empty Snippet Grouper")  # xgettext cannot handle f-strings
+            return f"{empty_grouper} - {self.pk}"
         return snippet_qs.first().name or super().__str__
 
     def snippet(self, show_editable=False):  # NOQA: FBT002
@@ -108,6 +111,16 @@ def get_preview_url(self):
             args=[self.id],
         )
 
+    def delete(self, *args, **kwargs):
+        # to avoid orphaned grouper instances,
+        # check if this snippet was the only one connected to it
+        # and if so, delete the grouper instance as well
+
+        if not Snippet.admin_manager.filter(snippet_grouper=self.snippet_grouper).exclude(id=self.id).exists():
+            self.snippet_grouper.delete()
+
+        return super().delete(*args, **kwargs)
+
 
 # Plugin model - just a pointer to Snippet
 class SnippetPtr(CMSPlugin):