Re: divert()/m4_divert() broken in autoconf-2.64+

[Ralf Wildenhues]

* Mike Frysinger wrote on Tue, Nov 24, 2009 at 06:12:53PM CET:
> On Tuesday 24 November 2009 08:28:22 Ralf Wildenhues wrote:
> > What's more, the example as you originally posted it (and I remember a
> > very similar real-world example) used diversions "by accident" so to
> > speak: there was no real need or intentional exploitation of diversion
> > functionality at all.  It would be a lot easier to argue for a better
> > API from the Autoconf side if there was some legitimate use case.
> 
> afact, the code is trying to use diversions to delay all the internal 
> autotool 
> output until later and put all the package-generated output up front.  i 
> thought it would be easier to analyze a <10 line script than a 1500+ line 
> script that also uses tons of macros.  if you want the actual code, download 
> the latest php release and read its configure.in.

Please link to such real-world examples right away, it cost me two
emails now and 15 minutes wasted on this bug report, with
absolutely no knowledge gained; without the PHP hint, I could still
not be sure whether we are talking about the same code, and would be
completely off two months in the future.  I've dowloaded
http://www.php.net/get/php-5.3.1.tar.bz2/from/a/mirror now.

We've had this bug report before.  As I don't know whether PHP was
mentioned back then, let's at least do it now so the next reporter
has no excuse of not finding the message in the mail archive.  The
conclusion back then was IIRC: just remove all the diverts, they
were useless with the Autoconf 2.13 that php-5.3.1/configure was
generated with, they were useless with Autoconf 2.61, and they are
broken with current Autoconf.  Simple as that: this is a bug in PHP.

Just FTR, I've actually tried to remove the diverts now to ensure that
there were no semantic changes with either 2.13 or 2.61.

> this also doesnt account for the second example i posted which simply results 
> in broken scripts as soon as diversions are used.

Are you talking about this one?
<http://thread.gmane.org/gmane.comp.sysutils.autoconf.bugs/7028/focus=7033>
What's the rationale for this code?  It is just as nonsensical AFAICT,
but maybe there is a larger version of it with a bug that has some
reason to use diversions?

Thanks,
Ralf