Hi

after a pip reinstall, my mailman (3.3.10, on mariadb) fails with:

2026-09-26 22:08:25 [FALCON] [ERROR] GET /3.1/lists?advertised=true&count=0&page=1 => Traceback (most recent call last): File "/opt/mailman/venv/lib/python3.11/site-packages/falcon/app.py", line 481, in __call__ responder(req, resp, **params) File "/opt/mailman/venv/lib/python3.11/site-packages/mailman/rest/lists.py", line 342, in on_get resource = self._make_collection(request) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/mailman/rest/helpers.py", line 171, in _make_collection start, total_size, collection = self._paginate( ^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/mailman/rest/helpers.py", line 153, in _paginate total_size = len(collection) ^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/mailman/utilities/queries.py", line 48, in __len__ .scalars(select(func.count()).select_from(self._query)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "<sqlalchemy generated _generative() wrapper for sqlalchemy.sql.selectable.Select.select_from>", line 2, in select_from return target(fn, self, *froms) ^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/base.py", line 296, in _generative x = fn(self, *args, **kw) ^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/selectable.py", line 6631, in select_from self._from_obj += tuple( ^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/selectable.py", line 6632, in <genexpr> coercions.expect( File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/coercions.py", line 434, in expect return impl._implicit_coercions( ^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/coercions.py", line 1287, in _implicit_coercions self._raise_for_expected(element, argname, resolved) File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/coercions.py", line 705, in _raise_for_expected super()._raise_for_expected( File "/opt/mailman/venv/lib/python3.11/site-packages/sqlalchemy/sql/coercions.py", line 528, in _raise_for_expected raise exc.ArgumentError(msg, code=code) from err sqlalchemy.exc.ArgumentError: FROM expression, such as a Table or alias() object expected, got <sqlalchemy.sql.selectable.Select object at 0x7f1a27269050>. To create a FROM clause from a <class 'sqlalchemy.sql.selectable.Select'> object, use the .subquery() method. (Background on this error at: https://sqlalche.me/e/21/89ve)

[26/Sep/2026:22:08:25 +0200] "GET /3.1/lists?advertised=true&count=0&page=1 HTTP/1.1" 500 38 "-" "GNU Mailman REST client v3.3.5"

I tried to add:

debug: yes to [database]

and

[logging.database] level: debug path: mailman.database.log

But i cannot get more details when the error happens. Any hints to help me debug the problem?

many thanks, simon