Subject: Re: bug#48801: 28.0.50; [PATCH] Feature suggestion gnus-retrieve-headers check for nov-is-evil when agent is enabled

From: Alex Bochannek <[email-masked]>
Date: Wed, 09 Jun 2021 11:05:14 -0700

Lars Ingebrigtsen <[email-masked]> writes:

> Alex Bochannek <[email-masked]> writes:
>
>> However, I don't see a way to set `nntp-nov-is-evil' for a group in a
>> way that would still be true when it is part of a virtual group.
>
> Perhaps the easiest would be to create a separate select method for
> these groups that has nntp-nov-is-evil set as a select method variable.

That's awesome, it works! I wasn't even considering this option, but it
makes perfect sense.

How about adding this to the documentation?

2021-06-09  Alex Bochannek  <[email-masked]>

	* doc/misc/gnus.texi (To From Newsgroups): Document extra header
          nnvirtual group scenario

diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 32ba5aee92..18c4b091d3 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -5246,6 +5246,13 @@ To From Newsgroups
 Be aware, though, that this will make entering an @acronym{NNTP} group
 much, much slower, so this is not recommended.
 
+One particular scenario in which it can be desirable to not use
+@samp{XOVER} is for @code{nnvirtual} groups in order to support
+limiting by extra headers (e.g., by the newsgroup of its component
+groups.) Because group parameters are not inherited, a separate select
+method for the component groups with the appropriate
+@code{nov-is-evil} set as a method variable is required.
+
 
 @node Summary Buffer Mode Line
 @subsection Summary Buffer Mode Line

>> As an experiment, I globally set `nntp-nov-is-evil' to `t' and disabled
>> the agent to see if it even works. I ran into a lot of problems where
>> Gnus lost track of the unread messages for simple NNTP groups. Is this
>> expected or is this potentially a bug?
>
> Sounds like a bug to me.

I must have gotten myself into an undefined state last night, can't
reproduce.

Thank you for your help! Learned a lot about how virtual groups work in
the process of trying to get this to work :)

-- 
Alex.