fix: do not update LMS user during retirement

1. Modifying users is already handled by the LMS retirement pipeline.
The `forum` library should not alter LMS users during retirement.
2. Changing the email to an empty string results in integrity errors
in the MySQL backend, because the email must be unique.

Author: Agrendalath

CHANGELOG.rst

@@ -16,6 +16,14 @@ Unreleased
 
 *
 
+0.3.8 - 2025-10-21
+******************
+
+Fixed
+-----
+
+* Do not modify LMS users during retirement — this is handled by the LMS retirement pipeline.
+
 0.3.4 – 2025-08-13
 ******************
 

forum/__init__.py

@@ -2,4 +2,4 @@
 Openedx forum app.
 """
 
-__version__ = "0.3.7"
+__version__ = "0.3.8"

forum/api/users.py

@@ -6,7 +6,7 @@
 import math
 from typing import Any, Optional
 
-from forum.backend import get_backend
+from forum.backend import get_backend, is_mysql_backend_enabled
 from forum.constants import FORUM_DEFAULT_PAGE, FORUM_DEFAULT_PER_PAGE
 from forum.serializers.thread import ThreadSerializer
 from forum.serializers.users import UserSerializer
@@ -135,14 +135,11 @@ def retire_user(
     user = backend.get_user(user_id)
     if not user:
         raise ForumV2RequestError(f"user not found with id: {user_id}")
-    backend.update_user(
-        user_id,
-        data={
-            "email": "",
-            "username": retired_username,
-            "read_states": [],
-        },
-    )
+    data: dict[str, Any] = {"read_states": []}
+    if not is_mysql_backend_enabled(course_id):
+        data["username"] = retired_username
+        data["email"] = ""
+    backend.update_user(user_id, data=data)
     backend.unsubscribe_all(user_id)
     backend.retire_all_content(user_id, retired_username)