Re: Bug: "possibly undefined macro: AC_MSG_ERROR"

[Hans Aberg]

On 4 Mar 2008, at 08:16, Ralf Wildenhues wrote:

> > But two autoconf in a row (on a new darcs download) works.
>
> No, it doesn't.

Yes it does.

> You need to run aclocal before running autoconf.

It id not work for me.

> If you don't do that, autoconf will not see the macro definitions for
> AM_INIT_AUTOMAKE, AM_CONDITIONAL, GTKHS_PROG_CHECK_VERSION, ...

I think autoconf runs aclocal, but running aclocal first did not work  
for me.

> The fact that autoconf doesn't warn the second time is due to caching
> (it doesn't even run the autom4te program the second time, which is  
> the
> one that is warning).

Yes, sure.

> The real problem here is that the warning messages are confusing/ 
> wrong:
> For example, this warning:
>
> > configure.ac:101: error: possibly undefined macro: AC_MSG_ERROR
>
> is triggered because of this code:
>
> GTKHS_PROG_CHECK_VERSION($GHC_VERSION, -lt, 6.4, [
>   AC_MSG_ERROR([Gtk2Hs requires GHC 6.4 or later])])
>
> which is in line 113, and which is not expanded correctly unless a  
> macro
> definition of GTKHS_PROG_CHECK_VERSION exists.  The problem is that
> autom4te does not track output file lines matching input file  
> lines, and
> thus only warns about the first instance found in the input file.

Yes, but in the altered version, configure.ac starts:
----
dnl with parts stolen from Manuel Chakravaty, Sven Panne and Micheal  
Weber
dnl
dnl This library is free software; you can redistribute it and/or
dnl modify it under the terms of the GNU Library General Public
dnl License as published by the Free Software Foundation; either
dnl version 2 of the License, or (at your option) any later version.
dnl
dnl This library is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
dnl Library General Public License for more details.
dnl
dnl You should have received a copy of the GNU Library General Public
dnl License along with this library (COPYING.LIB); if not, write to  
the Free
dnl Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA   
02111-1307  USA

dnl  
######################################################################
dnl Process this file with autoconf to produce a configure script.
dnl  
######################################################################

AC_INIT([gtk2hs],[0.9.12.2])
AM_INIT_AUTOMAKE
....
----

with an error on AM_INIT_AUTOMAKE. How is that to be fixed.

> Not sure if line tracking can be implemented easily and efficiently.
>
> As a workaround, you should consider adding
>   m4_pattern_forbid([^GTKHS_])
>
> early in the configure.ac script, which will at least add the right
> warnings as well.

That would only be a bug workaround. WHat is the bug, and how is it  
fixed?

  Hans Aberg