[Mutt] #3987: Bug in Yahoo Mail where body contains an empty text attachment if sent through mutt

[Mutt]

#3987: Bug in Yahoo Mail where body contains an empty text attachment if sent
through mutt
---------------------+----------------------
Reporter: Peter92 | Owner: mutt-dev
Type: defect | Status: new
Priority: minor | Milestone:
Component: mutt | Version: 1.5.24
Keywords: |
---------------------+----------------------
Same issue as here: https://dev.mutt.org/trac/ticket/3970

Like the above ticket, I've been finding either TEXT.txt or 1.txt (if
other attachments are present) in any email sent via mutt. With a bit of
narrowing down options I think I found the culprit, but have no idea how
to fix it.

As you can see at https://forums.yahoo.net/t5/Temporary-Errors/Content-
Disposition-inline-headers-not-being-respected/td-p/226349, Yahoo Mail
doesn't like the "Content-Disposition: inline" header, and will treat the
body as an attachment. It's more of a bug on the side of Yahoo, but it
should probably be a lot easier to fix in mutt.

Looking at a few of my other emails, it appears most don't contain that
line. I've attempted overriding the line but it didn't work, is there
anyway to disable it?

Here is the pastebin of one of the emails with the issue, as you can see
there is no actual attachment: https://pastebin.com/tzYEsL1S

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Ticket URL: <https://dev.mutt.org/trac/ticket/3987>
Mutt <http://www.mutt.org/>
The Mutt mail user agent

[Mutt]

#3987: Bug in Yahoo Mail where body contains an empty text attachment if sent
through mutt
----------------------+----------------------
Reporter: Peter92 | Owner: mutt-dev
Type: defect | Status: new
Priority: minor | Milestone:
Component: mutt | Version: 1.5.24
Resolution: | Keywords:
----------------------+----------------------

Comment (by kevin8t8):

This isn't "more of" a bug on the side of Yahoo; it's unequivocally
Yahoo's issue (which, strangely, I still can't reproduce).

Peeking at RFC 2183, the abstract at the very beginning says:
It specifies the "Content-Disposition" header field, which is optional
and valid for any MIME entity ("message" or "body part").

and to make it perfectly clear, section 2.10 plainly states:
It is permissible to use Content-Disposition on the main body of an
[RFC 822] message.

Furthermore, as if it weren't ridiculous enough that they are mishandling
a 20-year old RFC, the header itself says {{{inline}}}. Sigh. Okay,
enough ranting, it's not as if this is your fault.

I need to take a closer look at the code to see what, if anything, is
possible. The code for writing headers and body are reused in many
situations, and things like $fcc_attach, encryption, signing, and
$fcc_clear, make this less easy than one might initially think.

--
Ticket URL: <https://dev.mutt.org/trac/ticket/3987#comment:1>
Mutt <http://www.mutt.org/>
The Mutt mail user agent

[Mutt]

#3987: Bug in Yahoo Mail where body contains an empty text attachment if sent
through mutt
----------------------+----------------------
Reporter: Peter92 | Owner: mutt-dev
Type: defect | Status: new
Priority: minor | Milestone:
Component: mutt | Version: 1.5.24
Resolution: | Keywords:
----------------------+----------------------

Comment (by Peter92):

Haha thanks, for the record it doesn't appear to be all Yahoo accounts
(tested with a friend who is on yahoo.fr, both our accounts are old but
his didn't have the issue), but if you'd want to try at some point I can
pass you an unused account where it does happen.

I'd use gmail instead, but the 1tb limit Yahoo has is pretty nice for
backing up various bits :)

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Ticket URL: <https://dev.mutt.org/trac/ticket/3987#comment:2>
Mutt <http://www.mutt.org/>
The Mutt mail user agent