bug#13524: Improving user experience for non-recursive builds

[Peter Rosin]

On 2013-01-22 10:18, Stefano Lattarini wrote:
> [+cc bug-automake, so that we won't forget about the issue]
> [future replies should drop the automake list]
> 
> On 01/22/2013 02:22 AM, Miles Bader wrote:
>> Stefano Lattarini <address@hidden> writes:
>>> The best solution is on the user-side IMHO: fix the build system to
>>> use less (ideally none) make recursion.  Both the parallel and serial
>>> testsuite harness should support that setup OOTB.
>>
>> It would be nice if automake had some more features for that...
>>
> Indeed (albeit the present situation is already mostly good enough
> for most medium-sized packages).
> 
>> E.g., if I have a directory "foo" that has sources etc, and builds
>> some specific targets, then I can isolate the automake stuff for foo
>> by using an include file "foo/Makefile.am.inc" or something, and then
>> putting an appropriate include in the top-level Makefile.am.
>>
>> But it's a bit annoying, in that AFAICT, all filenames, etc, in foo's
>> Makefile fragment must explicitly include the directory name.
>>
> Yes, and this issue has come up several times already.  Nobody has
> been bothered enough to attempt a patch, though, at least so far.
> 
>> E.g., if it builds a library, "foo/Makefile.am.inc" might look like:
>>
>>    libfoo_a_SOURCES = foo/oink.c foo/barf.c foo/barf.h ...
>>
>> For longish directory names, this can really bloat things up...
>>
> Someone (probably Eric Blake, but I'm not 100% sure) once noted that this
> issue could be mitigated with simple indirections with usual make macros:
> 
>   d1 = wow/a/very/very/insanely/long/directory/name
> 
>   wow_a_very_very_insanely_long_directory_name_prog_SOURCES = \
>    $(d1)/a.c $(d1)/b.c ... $(d1)/z.c
> 
>> It would be really cool if there was some way of telling automake
>> "hey, for every filename mentioned in this file, try to use a prefix
>> of ..."
>>
> This is probably too automatic; but Bob Friesenhahn suggested Automake
> could recognize special substitutions, like %CURDIR% and %XCURDIR%, so
> that you could simply use in
> 
>     %XCURDIR%_prog_SOURCES = %CURDIR%/a.c %CURDIR%/b.c ... %CURDIR%/z.c
> 
> in 'wow/a/very/very/insanely/long/directory/name/local,.mk', include this
> '.mk' fragment from the top-level Makefile.am, and have DTRT.  I think
> that could be implemented in a simple pre-processing step, before
> Automake even parses the Makefile contents (this too was Bob's suggestion,
> IIRC); in which case, the change would probably be unobtrusive and mostly
> safe.  Patches (even WIP) are welcome.

This is proof of concept, and I'm not a perl hacker etc, but it seems to
work ok. Feel free to improve or toss or add documentation or whatever :-)

Patch is based on the maint branch, but being a new feature it perhaps
belongs on master instead. But as I said, do what you want with it...

Cheers,
Peter

0001-reldir-Add-support-for-relative-names-in-included-fr.patch
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