[Freeciv-Dev] Re: (PR#7390) python code generators and BUILT_SOURCES

["Raimar Falke" <i-freeciv-lists@xxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=7390 >

On Sat, Feb 07, 2004 at 10:02:24AM -0800, Jason Dorje Short wrote:
> 
> <URL: http://rt.freeciv.org/Ticket/Display.html?id=7390 >
> 
> Raimar Falke wrote:
> > <URL: http://rt.freeciv.org/Ticket/Display.html?id=7390 >
> > 
> > On Fri, Feb 06, 2004 at 06:20:49PM -0800, Jason Dorje Short wrote:
> > 
> >><URL: http://rt.freeciv.org/Ticket/Display.html?id=7390 >
> >>
> >>Jason Dorje Short wrote:
> >>
> >>><URL: http://rt.freeciv.org/Ticket/Display.html?id=7390 >
> >>>
> >>>I ran across
> >>>
> >>>http://www.gnu.org/software/automake/manual/html_node/Sources.html#Sources
> >>>
> >>>where it explains dependency calculations and how they affect two-stage 
> >>>builds.
> >>>
> >>>It seems to me that a normal build (after a clean cvs checkout) succeeds 
> >>>only by chance; because the generator happens to be run first.  To 
> >>>formalize this perhaps a BUILT_SOURCES directive should be added.
> >>
> >>Hmm.
> >>
> >>Obviously a build of a clean cvs checkout will work, since the built 
> >>sources are included in it already.
> >>
> >>What might fail is if you change packets.def and then recompile.  If it 
> >>so happens that (for instance) packets.o is compiled before 
> >>packets_gen.h, then the compilation may not be correct.  A second run of 
> >>"make" would be required to fix it.
> > 
> > 
> > The extra dependency:
> > 
> >   packets_gen.h packets_gen.c: packets.def generate_packets.py
> >           ./generate_packets.py
> > 
> > should take care of this. Or do I miss something here?
> 
> You do, but so do I.
> 
> The dependency that isn't already known is
> 
>    packets.c : packets_gen.h
> 
> since these .c : .h dependencies are generated as a side effect of 
> compilation (in .deps).  So I think if you get a clean checkout, change 
> packets.def, and then try to compile you _could_ come up with a wrong 
> compilation because packets.o is compiled before packets_gen.h.  Most 
> likely the linking step will fail.  This will be fixed by running "make" 
> a second time.

But isn't this a generic problem of the dependcy generation if some
*.h/*.c files are generated?! Looks like an misfeature of automake.

Shoul/can we add 
packets.c : packets_gen.h
?

        Raimar


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