Re: groff now undoing .ad settings after .IP

[G. Branden Robinson]

Hi Russ,

An uncharacteristically brief response from me this time.  ;-)

At 2024-03-17T14:10:18-0700, Russ Allbery wrote:
> Okay, I think this narrows it down.  The Perl 5.40 release is coming
> up, and I'd like to get the next release of podlators into it, with
> the hope that Debian will go to Perl 5.40 before the trixie release.
> 
> I think I have two options for the upcoming podlators 6.0.0 release:
> 
> * Do nothing.  Justification will be broken with groff 1.23 and fixed
>   with groff 1.24, which will hopefully make it into the trixie
>   release.
> 
> * Add ".if n .ds AD l" to the preamble, and leave ".if n .ad l" after
>   .TH as is.  This will make the formatting work everywhere the way
>   that it historically has (although will get pod2man output no closer
>   to supporting AD properly) and means that the time frame for groff
>   1.24 becomes irrelevant to podlators, at the cost of an additional
>   line in every generated man page.
> 
> I think I'm leaning towards the second option because it's simpler and
> provides the maximum decoupling of timelines, and one additional line
> in the preamble isn't too much of a price.  But I could be talked out
> of it if anyone thinks that's the wrong approach.

I will not attempt to do so.  I spent more lines than that making sure
groff 1.23's man pages would keep rendering on older groffs (despite
using the new `MR` macro), because some sites snarf up the pages and
serve them using older programs.

> Note that this will mean the creation of a whole lot of man pages in
> the wild that override the AD register, which will probably be with us
> for many years to come.  (But this is already true of all the man
> pages with ".if n .ad l", which is arguably an even bigger hammer.)

Agreed.  (By the way, `AD` is a string, not a register.  It takes a
letter instead of a number as a value.)

> I can then revisit and potentially add more complicated code should we
> figure out a way for pod2man to change the nroff default justification
> but still honor AD if set.

Yes.  And if by some chance you get some user who howls at you for
clobbering their clearly expressed `AD` preference for full
justification, you can point them to this thread in confidence that the
groff guy behind the feature won't join them in condemning you.

This feels like one of those challenges where I need to context-switch
my brain to some other problem for a while, and maybe the eureka will
come unbidden.

Regards,
Branden

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