Mark Sapiro writes:
On 4/14/22 08:21, Stephen J. Turnbull wrote:
Yes. The C-T-E on all the multipart parts was quoted-printable, not allowed under RFC 2045.
That's what I expected (we're talking about Apple Mail), but thanks for confirming.
The Python email library says the message is defective. Mailman's lmtp runner in turn rejects the defective message with a 501 status https://gitlab.com/mailman/mailman/-/blob/master/src/mailman/runners/lmtp.py...
It could accept a defective message or one with specific defects, but this is problematic for further processing. For example, at least one MUA, Thunderbird, renders such a message with an empty body.
Sure, but that's not our problem. I mean, I have my MUA set to ignore HTML so I get empty bodies all the time! :-) We are perfectly within our rights to just let the Apple Mail and Thunderbird users fight about it. :-) If it causes problems for *our* processing, that's another matter. I don't see why it would, though.
Whether we *want* to do that depends on how much trouble that causes for our main constituency (list and site admins), and whether we can provide discoverable documentation of the problem. My take is that this seems to be an extremely rare problem, and at least some MUAs are able to read the message, so we should let it through.
If we wanted to be really obnoxious, we could add a header to the message
This message does not conform to mail standards.
Some clients may omit some or all of the content.Or we could make passing it an option, perhaps as a pseudo-content type in "Pass these content types" or as a separate option.
I feel strongly enough that Postel implies "let it through" that I'll write up a PR shortly (a few days). Sleep on it, we bring in Abhilash and I guess Barry?, and if you all still don't like it, veto it -- my time is no big deal, it'll only be an hour to put it together I think.
Steve