Three IMAP connection leaks were recently fixed via try/finally
(#1325, #1330, #1423). This commit applies the same pattern to the
remaining callsites that still used inline logout-only cleanup.
routes/email_helpers.py:
- _fetch_sender_thread_context: conn was uninitialized when the outer
try/except returned early on connect failure, causing the finally
block to crash on conn.close()/conn.logout(). Merged the two
separate try blocks into one and added conn=None guard.
- _pre_retrieve_context: ctx_conn.logout() was inside the loop body
with no finally, so any exception in the folder/search loop leaked
the socket. Moved cleanup into a finally block with ctx_conn=None
guard.
mcp_servers/email_server.py:
- _list_emails: multiple inline conn.logout() calls on early-return
paths; exception between them leaked the socket. Wrapped in
try/finally.
- _read_email: same pattern — four separate logout() calls replaced
by a single finally block.
- _reply_to_email: logout() called before the error check, so an
exception in conn.select() leaked the socket. Wrapped in
try/finally.
- _download_attachment: same pattern as _reply_to_email.
Also adds tests/test_imap_leak_fixes.py with 9 regression tests (one
per function/failure-mode) that monkeypatch _imap_connect and assert
conn.logout() is called exactly once even when IMAP operations raise.
Lucas Daniel