Re: gnus-extra-headers

[Colin Baxter <m43cap@yandex.com>]

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.

Best wishes,

Colin Baxter.