RE: AC_SUBST_FILE regression in -cvs

[Peter Ekberg]

Stepan Kasal wrote:
> On Mon, Jul 11, 2005 at 01:53:09PM +0200, Peter Ekberg wrote:
> > With autoconf-cvs the @EXTRA_SYMBOLS@ is no longer found
> > [...]  Moving @EXTRA_SYMBOLS@ to a line of its own is not
> > a solution here since the EXPSYMS file should not have
> > any blank lines.
> 
> with autoconf-cvs, @EXTRA_SYMBOLS@ has to be on a line of its own.
> The whole line is deleted and replaced by the contents of the file.
> 
> So, actually, if EXPSYMS.in were
> ------8<------
> foo
> bar
> @EXTRA_SYMBOLS@
> ------8<------
> you'd get exactly what you want.
> 
> I believe this behaviour is more intuitive than the previous one
> (delete @EXTRA_SYMBOLS@ from the line and add the contents of the file
> after that line).
> 
> The problem is that if the resulting file is sensitive about extra
> whitespace, you cannot construct configure.ac which would work with
> both versions.

And that's the goal, of course...

> I see several possible solutions:
> 
> 1) All your developers (those who don't get their configure from the
> dist tarball) switch to autoconf-cvs and you can use the 
> simple solution suggested above.

Not acceptable for us.

> 2) If @EXTRA_SYMBOLS@ is the only substituted symbol in EXPSYMS.in,
> you could use a makefile rule to create EXPSYMS:
> ------8<------
> EXPSYMS: EXPSYMS.in EXPSYMS.extra
>       cat EXPSYMS.in EXPSYMS.extra >$@
> ------8<------
> EXPSYMS.extra can be generated either by ./configure, or by another
> make rule.

A bit convoluted, but EXPSYMS.extra is empty for most systems and
I would prefer if it didn't need to exist. Do you know if it need
to exist to not trigger some make error/warning in the above rule?

> 3) If there are more AC_SUBSTs in EXPSYMS.in, you can make use of the
> fact that EXPSYMS can have more sources, not only EXPSYMS.in.
> 
> For example:
> ------8<------
> rm -f EXPSYMS.extra
> if text $extra = yes; then
>       echo '_foo
> _bar' >EXPSYMS.extra
> else
>       >EXPSYMS.extra
> fi
> AC_CONFIG_FILES([EXPSYMS:EXPSYMS.in:EXPSYMS.extra])
> ------8<------
> or perhaps
> ------8<------
> expsyms_extra=
> if text $extra = yes; then
>       expsyms_extra=:EXPSYMS.extra
>       rm -f EXPSYMS.extra
>       echo '_foo
> _bar' >EXPSYMS.extra
> fi
> AC_CONFIG_FILES([EXPSYMS:EXPSYMS.in$expsyms_extra])
> ------8<------
> or
> ------8<------
> if text $extra = no; then
>       expsyms_src=EXPSYMS.in
> else
>       expsyms_src=EXPSYMS.in:EXPSYMS.extra
>       rm -f EXPSYMS.extra
>       echo '_foo
> _bar' >EXPSYMS.extra
> fi
> AC_CONFIG_FILES([EXPSYMS:$expsyms_src])
> ------8<------

Automake complains with:
configure.in:1545: required file `EXPSYMS.in$expsyms_extra' not found
for the 2nd of these, I believe it would complain for
the others as well for similar reasons.

Do you know of a way to silence that warning?

But it works!

> I hope some of the above solutions helps.

4) Write code in configure.ac to concatenate the desired EXPSYMS
file directly w/o help from AC_SUBST* (@EXTRA_SYMBOLS@ is the only
substituted symbol).

Thanks for your effort!

Cheers,
Peter