[MM3-users] messages with attachments, without text discarded silently

Using the current mailman version, I can reproduce the following:

• send a text-formatted email with attachment but without text body to a list.
• the msg will be received by mailman
• the msg shows up in shunt, the log shows: ile "/usr/lib/python3.12/email/message.py", line 343, in set_payload payload = payload.encode(charset.output_charset, 'surrogateescape') ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ UnicodeEncodeError: 'ascii' codec can't encode characters in position 10-17: ordinal not in range(128)

an attempt to unpickle the file leads to the same error. I know it's uncommon to send emails without txt but with attachments - but it may happen; at least we would welcome an error message.