Re: gnus-extra-headers

[Colin Baxter <m43cap@yandex.com>]

>>>>> Eric Abrahamsen <eric@ericabrahamsen.net> writes:

    > Colin Baxter <m43cap@yandex.com> writes:
    >> Hello Eric,
    >>>>>>> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
    >> 
    >> > Colin Baxter <m43cap@yandex.com> writes: >> Hello,
    >> >> 
    >> >> If emacs (tested with 27.2 and 28.0.50) is launched with -Q
    >> (or >> gnus-extra-headers has not been set explicitly by the
    >> user) then >> the variable gnus-extra-headers has the value:
    >> >> 
    >> >> gnus-extra-headers is a variable defined in ‘gnus-sum.el’.
    >> Its >> value is (X-Diary-Time-Zone X-Diary-Dow X-Diary-Year >>
    >> X-Diary-Month X-Diary-Dom X-Diary-Hour X-Diary-Minute To Cc >>
    >> Keywords Gcc Newsgroups X-GM-LABELS) Original value was (To Cc >>
    >> Keywords Gcc Newsgroups X-GM-LABELS)
    >> >> 
    >> >> You can customize this variable.
    >> >> 
    >> >> 
    >> >> This variable was introduced, or its default value was
    >> changed, >> in version 25.1 of Emacs.
    >> >> 
    >> >> Documentation: Extra headers to parse.
    >> >> 
    >> >> The X-Diary settings seem to come from nndiary.el, but there
    >> is >> nothing in the doc-string to indicate this.
    >> >> 
    >> >> Is this a bug? Is not the "Original value" of
    >> gnus-extra-headers >> incorrect?
    >> 
    >> > I don't think it's really a bug. If you don't use the nndiary >
    >> backend, those headers don't get added to `gnus-extra-headers', >
    >> and it has its "original value" as noted in *Help*. I don't think
    >> > there's any contract that says additional libraries can't >
    >> manipulate the value of customization options... is there?
    >> 
    >> True, but the user might suppose that using -Q ensures that no
    >> extra libraries are loaded. I would have thought that nndiary
    >> constitutes an extra library. If it does not and the library is
    >> germane to -Q then why omit any mention of it from
    >> gnus-extra-headers? I have quickly looked at NEWS for emacs-25.1
    >> but found nothing relevant.

    > If I start with "emacs -Q" and a minimal Gnus setup, the nndiary
    > isn't loaded and its values aren't added to
    > `gnus-extra-headers'. The odd thing is that in my usual Emacs/Gnus
    > set up, those values _are_ added, and I don't use nndiary or
    > gnus-diary.el. Hang on, let me force an error in there and see
    > exactly what's loading it.

    > Nope, I just restarted Emacs and Gnus, and did some other
    > Org/Diary/Calendar stuff for good measure, and now nothing has
    > triggered a load of 'nndiary, and the extra values aren't added.

    > Obviously something, somewhere, eventually triggers that load in
    > my setup, but it doesn't seem to happen by default. I'm quite
    > ready to believe that something is loading 'nndiary when it
    > doesn't need to, but so far I don't know what it is.

    > Maybe you could give it a shot? Delete nndiary.elc, stick a call
    > to (error) in nndiary.el,

How do I modify the file nndiary.el to achieve this?

    > and restart everything?

What I do know is that if nndiary is not present (.el) and (.elc) then
gnus-extra-headers becomes (To Cc Keywords Gcc Newsgroups X-GM-LABELS).

Best wishes,