bug#59121: 29.0.50; Gnus: Nnir is deprecated but not mention in the manual

["Björn Bidar via Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> Eric Abrahamsen <eric@ericabrahamsen.net> writes:
>>> I think the manual should mention that. I think such changes should be
>>> documented right a way in general.
>>
>> Do you mean that you recently upgraded Emacs, and got a deprecation
>> warning for a nnir-* variable, but there's no information in the Gnus
>> manual about migrating away from nnir?
>>
>> That does seem like an oversight...
>
> Here's a potential documentation patch.

> diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
> index 7bcf334297..578273aede 100644
> --- a/doc/misc/gnus.texi
> +++ b/doc/misc/gnus.texi
> @@ -21900,14 +21900,13 @@ About mairix
>  @uref{http://www.rpcurnow.force9.co.uk/mairix/index.html}
>  
>  Though mairix might not be as flexible as other search tools like
> -swish++ or namazu, which you can use via the @code{nnir} back end, it
> -has the prime advantage of being incredibly fast.  On current systems, it
> -can easily search through headers and message bodies of thousands and
> -thousands of mails in well under a second.  Building the database
> -necessary for searching might take a minute or two, but only has to be
> -done once fully.  Afterwards, the updates are done incrementally and
> -therefore are really fast, too.  Additionally, mairix is very easy to set
> -up.
> +swish++ or namazu, it has the prime advantage of being incredibly
> +fast.  On current systems, it can easily search through headers and
> +message bodies of thousands and thousands of mails in well under a
> +second.  Building the database necessary for searching might take a
> +minute or two, but only has to be done once fully.  Afterwards, the
> +updates are done incrementally and therefore are really fast, too.
> +Additionally, mairix is very easy to set up.
>  For maximum speed though, mairix should be used with mails stored in
>  @code{Maildir} or @code{MH} format (this includes the @code{nnml} back
> @@ -22545,6 +22544,20 @@ nnmairix caveats
>  

What about remote searches such as IMAP?
In any case since the search isn't asynchronous there's the caveat of
Gnus locking up Emacs until it is done.

This kinda goes out of the original topic but the manual doesn't mention
much what can used to reduce the download when IMAP is used (caching etc.).

> +@node nnir
> +@section Migrating from nnir
> +
> +@cindex nnir
> +
> +Gnus' previous search engine was called nnir, and is now obsolete.  If
> +you've upgraded Emacs and are now getting obsolete-variable warnings
> +about @code{nnir-*} variables, migration is fairly straightforward.
> +In addition to the variables raised by the warnings, all previous
> +engine-specific variables can be updated by simply replacing the
> +@code{nnir-} prefix with @code{gnus-search-}.  For instance,
> +@code{nnir-notmuch-program} is now @code{gnus-search-notmuch-program}.

The section should mention the exact version it was deprecated,
instead of now it should be "and is deprecated since <version>".
Something like a separate section about deprecated items could also be
very useful. Some guide around the internet set variables which are no
longer valid, if there is a section for each item deprecated
with an explanation it could help greatly.

Br,

Björn