bug#75123: [PATCH] Set makeinfo-run-command to texi2any when possible

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 75123@debbugs.gnu.org
> Date: Fri, 27 Dec 2024 09:16:59 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > In recent Texinfo, "makinfo" is an alias for "texi2any".  Make
> > `makeinfo-run-command` heed this request in the texinfo documentation:
> > 
> >     "Going forward, we ask authors of Texinfo documents to use only
> >     texi2any."
> > 
> > See (info "(texinfo) History").
> 
> Sorry, I'm against this change.  People still have old versions of
> Texinfo installed, including those where texi2any was not even
> present.  I understand what the Texinfo developers say as advice to
> people who install latest version of Texinfo, not as a general rule to
> other programs which invoke makeinfo.
> 
> In practice, in latest versions, 'makeinfo' is just a copy (or even a
> symlink) to texi2any.  So we gain absolutely nothing by this change,
> while the disadvantages for users who have old versions of makeinfo
> are clear and present.

A few more thoughts:

Some users could have local scripts named "makeinfo" somehow tailored
to DTRT for whatever reasons.  Invoking texi2any instead will break
those users, for no good reason.

In addition, executable-find looks for files with extensions in the
order specified by exec-suffixes, which could be different from the
order the shell looks for executables.  So this change might produce
subtle differences in behavior, at least in some cases.

I could support doing this the other way around: if "makeinfo" is not
found as an executable, fall back to texi2any (if that exists).  But
in that case, we need to make sure makeinfo-run-command  never ends up
being nil, because AFAICT the code is not prepared for that.  IOW, if
neither "makeinfo" nor "texi2any" is found, the value should be
"makeinfo", as it was before, not nil.