Weird goings on with make::empty()

[Gary Jennejohn]

On Wed, 4 Sep 2019 09:33:08 -0500
Kyle Evans <kevans at freebsd.org> wrote:

> On Wed, Sep 4, 2019 at 9:27 AM Enji Cooper <yaneurabeya at gmail.com> wrote:
> >
> >  
> > > On Sep 4, 2019, at 04:59, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
> > >
> > > On:
> > >
> > >    Repository Root: svn+ssh://repo.freebsd.org/base
> > >    Repository UUID: ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
> > >    Revision: 351809
> > >
> > > I built a kernel, but drm-current-kmod did not get compiled
> > > from the new world order in /usr/local/sys/modules
> > >
> > > Debugging I ended up doing this to src/sys/conf/kern.post.mk:
> > >
> > >    Index: sys/conf/kern.post.mk
> > >    ===================================================================
> > >    --- sys/conf/kern.post.mk    (revision 351809)
> > >    +++ sys/conf/kern.post.mk    (working copy)
> > >    @@ -77,12 +77,14 @@
> > >            ${target:S/^reinstall$/install/:S/^clobber$/cleandir/}
> > >     .endif
> > >     .for module in ${LOCAL_MODULES}
> > >    -.if !empty(module)
> > >    +    true "XXX A $(module) 2 ${LOCALBASE} 3 ${LOCAL_MODULES} 4 ${MODULES_WITH_WORLD}"
> > >    +#.if !empty(module)
> > >    +    true "XXX B $(module) 2 ${LOCALBASE} 3 ${LOCAL_MODULES} 4 ${MODULES_WITH_WORLD}"
> > >        @${ECHODIR} "===> ${module} (${target:S/^reinstall$/install/:S/^clobber$/cleandir/})"
> > >        @cd ${LOCAL_MODULES_DIR}/${module}; ${MKMODULESENV} ${MAKE} \
> > >            DIRPRFX="${module}/" \
> > >            ${target:S/^reinstall$/install/:S/^clobber$/cleandir/}
> > >    -.endif
> > >    +#.endif
> > >     .endfor
> > >     .endif
> > >     .endfor
> > >
> > > This gives me the expected output from buildkernel:
> > >
> > >    true "XXX A drm-current-kmod 2 /usr/local 3 drm-current-kmod 4 "
> > >    true "XXX B drm-current-kmod 2 /usr/local 3 drm-current-kmod 4 "
> > >
> > > If I leave in the ".if !empty(module)" line in, I only get:
> > >
> > >    true "XXX A drm-current-kmod 2 /usr/local 3 drm-current-kmod 4 "
> > >
> > > suggestions welcome...  
> >
> > (CCing Kyle)
> >
> > This behavior change is probably caused by r351799.
> >
> > I personally think the code before Kyle___s change and after it was buggy. It___s not word splitting LOCAL_MODULES before iterating over it.
> >  
> 
> I've backed out r351799 since it breaks usage of LOCAL_MODULES (though
> I really don't understand how empty works, apparently, and that makes
> me sad)... please advise on a correct path forward, because it's not
> clear to me.
> 

In Kyle's defence my testing of his patch was only with
LOCAL_MODULES= and LOCAL_MODULES="" in /etc/src.conf.  I don't
have any ports modules to be compiled with the kernel.

-- 
Gary Jennejohn