POP3 RETR drops the message body (returns empty message) #1

New Issue

2026-06-17T17:12:00+01:00

lyrathorpe commented

2026-06-17 17:12:00 +01:00

IMAPBackend.fetch_message (proxy_server.py:119) filters the imaplib FETCH response to top-level bytes only:

parts = [chunk for chunk in data if isinstance(chunk, bytes)]

Real imaplib returns the RFC822 literal inside a tuple, e.g.

[(b"1 (UID 1 RFC822 {N}", b"<raw message bytes>"), b")"]

The tuple is not bytes, so the body in tuple[1] is discarded and the client receives only the trailing b")". RETR is therefore broken against any real IMAP server.

The existing unit test passes only because DummyIMAP returns a flat list of bytes, which imaplib never produces.

Fix:

Extract the body from the tuple element (tuple[1]) of the FETCH response.
Update the test fixture to return the realistic tuple shape so the bug cannot regress.

Acceptance:

RETR returns the full message body against a tuple-shaped FETCH response.
Test fixture reflects real imaplib output.

IMAPBackend.fetch_message (proxy_server.py:119) filters the imaplib FETCH response to top-level bytes only: parts = [chunk for chunk in data if isinstance(chunk, bytes)] Real imaplib returns the RFC822 literal inside a tuple, e.g. [(b"1 (UID 1 RFC822 {N}", b"<raw message bytes>"), b")"] The tuple is not `bytes`, so the body in tuple[1] is discarded and the client receives only the trailing b")". RETR is therefore broken against any real IMAP server. The existing unit test passes only because DummyIMAP returns a flat list of bytes, which imaplib never produces. Fix: - Extract the body from the tuple element (tuple[1]) of the FETCH response. - Update the test fixture to return the realistic tuple shape so the bug cannot regress. Acceptance: - RETR returns the full message body against a tuple-shaped FETCH response. - Test fixture reflects real imaplib output.

lyrathorpe added the bug label 2026-06-17 17:12:00 +01:00

lyrathorpe referenced this issue from a commit

2026-06-17 17:22:29 +01:00

fix: correct POP3 RETR/TOP, static maildrop, and IMAP fetching

lyrathorpe referenced a pull request that will close this issue

2026-06-17 17:22:53 +01:00

Fix POP3/SMTP correctness and IMAP robustness #10

lyrathorpe closed this issue

2026-06-17 17:33:10 +01:00

lyrathorpe referenced this issue from a commit

2026-06-17 17:33:11 +01:00

Fix POP3/SMTP correctness and IMAP robustness (#10)