Re: $(srcdir) in man pages and other targets

[Stefano Lattarini]

Hi Patrice.

On 11/24/2012 10:15 AM, Patrice Dumas wrote:
> On Fri, Nov 23, 2012 at 09:39:21AM +0100, Stefano Lattarini wrote:
>>>
>>> Automake sort of checks it but not exactly.  For instance, if you have 
>>> the tool and it is rebuilt, the I don't think that automake can check
>>> that it is not rebuilt.
>>>
>> It does, *if* that file is not removed by "make distclean" (and
>> distributed files should never be).  For a long-winded example, see:
>> http://www.gnu.org/software/automake/manual/automake.html#Errors-with-distclean
> 
> You a re right, I didn't realize that correctly (though I have used make
> distcheck repeatedly...).
> 
>>> Another point is that you may trick automake too, which I believe is
>>> what happens with adding $(srcdir) to the reules
>>>
>> No, you wouldn't fool it, because "make distcheck" runs a VPATH build
>> with the srcdir made *readonly*.  So any attempt to modify or add a file
>> there will cause an error (unless your build rules use explicit calls to
>> "chmod u+w", but then you're asking for trouble).
> 
> Right, that's one side of the check, but if you create something in the
> $(srcdir), but you also distribute it, then "make distcheck" won't lead
> to a rebuild of the file and therefore you will miss that you did
> something wrong (creating a file in $(srcdir) although you should have
> created it in builddir)..  
>
I believe that, if you distribute a file, creating in $(srcdir) might
actually be the correct choice ...  For more background, see:

  <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10852>

> It may not be wrong in every cases, for instance it seems to me that it 
> makes sense to rebuild in $(srcdir) the Makefile fragments that are 
> included by automake.
> 
In that case, it is the *only* sane approach actually.  Automake (and
the other autotools, like aclocal and autoconf) are re-run by the
automatic remake rules present in automake-generated Makefiles only
from the srcdir (since they can only work from there), so any included
file that is in the builddir would not be found.

Regards,
  Stefano