[PATCH wayland v1 1/1] wayland-scanner.pc.in: prepend pc_sysrootdir

[Joe Konno]

On Fri, 16 Sep 2016 17:30:18 +0200
Arnaud Vrac <rawoul at gmail.com> wrote:

> On Fri, Sep 16, 2016 at 5:19 PM, Joe Konno <joe.konno at linux.intel.com>
> wrote:
> 
> > On Fri, 16 Sep 2016 10:53:32 +0300
> > Pekka Paalanen <ppaalanen at gmail.com> wrote:
> >  
> > > On Thu, 15 Sep 2016 15:22:12 -0700
> > > Joe Konno <joe.konno at linux.intel.com> wrote:
> > >  
> > > > From: Joe Konno <joe.konno at intel.com>
> > > >
> > > > In a cross-compilation environment with packages depending on
> > > > wayland-scanner, ensure the path to wayland-scanner is correct. Without
> > > > this patch, the path will _not_ point to the target environment but to
> > > > the host's, potentially leading to breakage.
> > > >
> > > > https://bugs.freedesktop.org/show_bug.cgi?id=97828
> > > >
> > > > Signed-off-by: Joe Konno <joe.konno at intel.com>
> > > > ---
> > > >  src/wayland-scanner.pc.in | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/src/wayland-scanner.pc.in b/src/wayland-scanner.pc.in
> > > > index 7b2a4c92e0e3..ec11a0bc982c 100644
> > > > --- a/src/wayland-scanner.pc.in
> > > > +++ b/src/wayland-scanner.pc.in
> > > > @@ -2,7 +2,7 @@ prefix=@prefix@
> > > >  exec_prefix=@exec_prefix@
> > > >  datarootdir=@datarootdir@
> > > >  pkgdatadir=@datadir@/@PACKAGE@
> > > > -wayland_scanner=@bindir@/wayland-scanner
> > > > +wayland_scanner=${pc_sysrootdir}/@bindir@/wayland-scanner
> > > >
> > > >  Name: Wayland Scanner
> > > >  Description: Wayland scanner  
> > >
> > > Hi,
> > >
> > > ok, so pc_sysrootdir points to the sysroot. I would just like to
> > > confirm that this really does what you intend. wayland-scanner is a
> > > build tool to be run on the host. Such tools get installed into the
> > > sysroot even when compiled for the host, not the target, yes?
> > >
> > > I read both http://dev.gentoo.org/~mgorny/pkg-config-spec.html and
> > > https://autotools.io/pkgconfig/cross-compiling.html but couldn't
> > > actually understand what is going on, perhaps because I never
> > > cross-compile.
> > >
> > > Hence I cannot offer a Reviewed-by, but I can offer:
> > > Acked-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > >
> > > (Not for the 1.12.0 release.)
> > >
> > > Are you using binary-compatible arches for both host and target? I'd
> > > like to see a test on a setup where the binaries are completely
> > > incompatible so that the host != target difference is obvious.  
> >
> > I'm struggling with this particular cross-compilation scenario as well, as
> > there's a fair bit of wonky overhead involved in the build process I'm
> > dealing
> > with. Figured I'd introduce the patch and solicit feedback early while I
> > continue digging.
> >
> > Your points are fair and the feedback's appreciated. I'll see about testing
> > this out a bit more with an incompatible binary target-- right now my host
> > is
> > Intel-based and my target is also Intel-based.
> >
> > I'll reply back once I feel convinced one way or the other. ^_^
> >  
> 
> Hi Joe,
> 
> I believe your patch is not right, as pq says the sysroot normally contains
> the code compiled for the target, which might not be compatible with the
> host.
> 
> I think the proper way to do this is to compile wayland for the host
> separately, and use ${CHOST}-pkg-config instead of pkg-config to get the
> wayland-scanner path. In practice you would call
> x86_64-linux-gnu-pkg-config --variable=wayland_scanner. The
> x86_64-linux-gnu-pkg-config utility will look for pkgconfig files in the
> host sysroot, instead of the target sysroot, allowing this use case to work.
> 
> Unfortunately not many packages do this correctly...
> 
> Regards,
> Arnaud

Thanks a mil, Arnaud. I appreciate your feedback. Some of my observations are
making more sense now, and I'm increasingly convinced this patch I submitted
isn't the solution Wayland's looking for (or needs).

Apologies for cluttering the list, Pekka and folks. I don't think this patch
as-is should be considered for inclusion.

Cheers, and thanks again!
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 836 bytes
Desc: OpenPGP digital signature
URL: <https://lists.freedesktop.org/archives/wayland-devel/attachments/20160916/23470b6c/attachment.sig>