Re: [PATCH] {maint} Document in detail some limitations of aclocal.

[Ralf Wildenhues]

Hello,

* Stefano Lattarini wrote on Thu, Nov 04, 2010 at 08:47:47PM CET:
> I've gone ahead and documented this non-obvious limitation, and another
> similar one regarding AC_DEFUN.  See the attached patch.
> 
> Ralf, ok to apply to maint?

There are a couple of things I don't like with the principle of this
patch: hard-coding limitations in the testsuite, and hard-coding
limitations and presenting them as such in the manual.  The latter makes
the project look bad, the other two are a maintenance hassle once and if
the code is improved.  We might even have to remove the section in the
manual once aclocal is fixed (which is really bad because it means URLs
to the per-node links to the manual will go bad).

That said, I think it is prudent to document *requirements* of aclocal
that the user of aclocal and authors of macro files must meet.  But
document them that way, and do it only if they can't be fixed.

I'm still not totally sure why aclocal didn't try to use traces, but one
reason I can think of is the following: macros from unrelated
third-party packages may otherwise interfere with each other; but also,
macros from different versions of the same third-party package might all
be found in the aclocal search path.  Can we please check history here
before committing to anything?

I cannot tell without experimenting (e.g., installing lots of *-dev
distro packages on my box) whether this is a problem now, or would be
a problem when tracing with the Autoconf-without-aclocal language (which
is defined by Autoconf already) or with Gary's proposed new language.

A problem to take into account is that if aclocal fails due to macro
interaction for some user, she might not be able to do anything about it
(because she is not root) thus making the whole installation a bit
unusable.

Thanks,
Ralf

> Document in detail some limitations of aclocal.
> 
> * doc/automake.texi (Limitations of aclocal): New section.
> * tests/aclocal-limit-defun.test: New test, checking that the
> aclocal limitation(s) exposed in the newly added manual section
> does really hold.
> * tests/aclocal-limit-include.test: Likewise.
> * tests/Makefile.am (TESTS): Updated.
> * .gitignore: Updated.
> * THANKS: Updated.
> 
> From a report by Nick Bowler.