Re: Unexpected fill-paragraph behaviour in message-mode

[Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

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> Subject: Weird fill-paragraph behaviour
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> Emacs has weird wrapping behaviour in message mode. To reproduce,
> first (M-x message-mode).
>
> Filling this long line (M-q anywhere on it) joins it with the following
> indented text, which it should not because there is an empty line marking
> the end of this paragraph:

It looks like `message-mode` thinks you're still in the header part of
the message because of the lack of the separator that `message-mode`
uses (i.e. "--text follows this line--")

> Quickly skimming message.el, it looks like message-mode (only?) supports
> mail and news. In those cases, RFC 5322 §2.1 [0] and RFC 5536 §2 [1]
> give the following separator:

These RFCs document the format of messages when they leave the MUA, but
the format within the MUA (e.g. within a `message-mode` buffer) if up to
the MUA, of course.

> (re-search-forward
>        (concat "^" (regexp-quote mail-header-separator) "$")

For a more graceful degradation, `message-mode` should treat an empty
line as the header separator when the "--text follows this line--"
thingy is missing, indeed.  [ I wouldn't be surprised if `message-mode`
ends up generating incorrectly formatted messages if you include an
empty line the header.  ]

Patch welcome :-)


        Stefan