Re: Recursive targets for the user

[Ralf Wildenhues]

Hello Stefano,

* Stefano Lattarini wrote on Fri, Oct 08, 2010 at 02:46:58AM CEST:
> What I'd like to do is to allow the developers to extend the nonrecursive
> part of any recursive `foo' rule (be it user-defined or automake-defined)
> with a simple:
> 
>   foo-local: foo-extra-deps
> 
> *without causing automake to tweak the generated Makefile.in or to take
> different codepaths*.

This is a valid feature request, but orthogonal to the feature request
we have discussed so far.  Can we also keep its discussion and its
eventual addition separate, for both user-defined and automake-defined
recursive targets, please?

I don't yet see much chance for regression yet, but the feature does
violate the "given Makefile.am, let Makefile.in be as simple as
possible" development guide line.  It would not be easy to draw a
consistent line: what about *-hook extensions defined only in
GNUmakefile?  What about things like BUILT_SOURCES?  Either of those
would trigger extra forks, maybe even extra make recursions with
associated undesirable slowdown effects.  Then what about special
variables like bin_PROGRAMS?  If we don't have any _PROGRAMS in
Makefile.am (or included files), then we completely avoid the
compilation machinery; OTOH, it only needs a
  noinst_PROGRAMS =

line to enable it, just as it only needs a
  all-local:

line to enable the -local hook for all (and such a line can easily be
script-added to Makefile.am files in need).  IOW, the current behavior
is very consistent, while your proposed extension is less consistent.

Thanks,
Ralf