Re: [PATCH v3 3/4] imap-send: check git send-email copies like other messages

[Patrick Steinhardt <ps@pks.im>]

On Thu, Oct 22, 2026 at 06:56:24AM +0000, Harald Nordgren via GitGitGadget wrote:
> From: Harald Nordgren <haraldnordgren@gmail.com>
> 
> The copy that git send-email --imap-sent-folder pipes to imap-send
> starts with a "From git-send-email" line. 04133f5bc4 (send-email: add
> ability to send a copy of sent emails to an IMAP folder, 2025-08-12)
> made imap-send count such a message when it has From and To headers,
> without looking for Date and Subject. Without that special case the
> copy would not be counted at all, because git send-email writes
> Subject before Date.
> 
> Now that the headers are accepted in any order, the special case is no
> longer needed. The copy carries the same headers git send-email sends
> over SMTP, which always include From, Subject and Date, so it passes
> the check for other messages. A To header is no longer required, the
> same as for any other message.

You argue from the perspective of git-send-email(1) generating the mbox.
But what if somebody writes an mbox via a different script that doesn't
write a Date or Subject line? Based on RFC 5322, the Date header is
mandatory, so I think it's safe to assume it always exists. But the
Subject header is only specified as "SHOULD exist".

Now we probably don't care about such edge cases, so tightening the
rules is likely going to be fine. But I don't think that's sufficiently
explained.

Patrick