Re: [bug#42738] [PATCH v4] gnu: emacs: Update to 27.1.

[Ludovic Courtès]

Hi Mark,

Mark H Weaver <mhw@netris.org> skribis:

> Ludovic Courtès <ludo@gnu.org> wrote:
>> Mark H Weaver <mhw@netris.org> skribis:
>>
>>> (define-public emacs-next
>>>   (let ((commit "c36c5a3dedbb2e0349be1b6c3b7567ea7b594f1c")
>>>         (revision "0")
>>>         (emacs-version "27.0.91"))
>>>     (package
>>>       (inherit emacs)
>>>       (name "emacs-next")
>>>       (version (git-version emacs-version revision commit))
>>>       (source
>>>        (origin
>>>          (inherit (package-source emacs))
>>>          (method git-fetch)
>>>          (uri (git-reference
>>>                (url "https://git.savannah.gnu.org/git/emacs.git";)
>>>                (commit commit)))
>>
>> This can be handled with ‘--with-git-url’.
>
> I think that wouldn't work in this case, because we also need to
> preserve the existing 'patches' and 'snippet' fields, which I arranged
> to inherit above via (inherit (package-source emacs)).  That probably
> deserves a comment, since it's easily overlooked.
>
>>>          (sha256
>>>           (base32 "0mlrg2npy1r79laahkgzhxd1qassfcdz8qk1cpw7mqgf6y5x505h"))
>>>          (file-name (git-file-name name version))))
>>>       (native-inputs
>>>        `(("autoconf" ,autoconf)      ; needed when building from trunk
>>>          ,@(package-native-inputs emacs)))
>>
>> For this, we’d need a new ‘--with-extra-input’ package transformation
>> option or similar.  That way, we wouldn’t even need an ‘emacs-next’
>> package: people would just run
>>
>>   guix install emacs --with-git-url=… --with-extra-input=autoconf
>
> There's also the 'native-search-paths' field, which cannot simply be
> inherited because of the version number embedded within EMACSLOADPATH.
> This particular issue could be avoided if the 'native-search-paths'
> field were a function of the version number, but that raises migration
> issues and I'm not sure it's worth it.
>
> What do you think?

Ah yes, both good points that I had overlooked.

Thanks,
Ludo’.