[Fedora-packaging] Re: GNUstep filesystem layout discussion

[Axel Thimm]

Hi,

On Sat, Aug 23, 2008 at 02:03:23PM -0400, Michel Salim wrote:
> What
> ===
> GNUstep is a Obj-C-based framework, similar to Mac OS X's Cocoa
> 
> State of GNUstep in Fedora
> ================
> GNUstep has long been excluded from Fedora due to its non-standard
> filesystem layout. Recently, however, its support for being installed
> under the FHS layout has improved. gnustep-make is now in Fedora.
> There are some problems with the current layout used by Fedora; see
> below.
> 
> Other distributions
> ===========
> Debian and its derived distributions have the complete GNUstep stack
> already packaged. The file system layout they adopted seem to be a
> flattened FHS layout.
> 
> Current problems
> ==========
> OpenStep/GNUstep/Cocoa allow for application bundles: self-contained
> directories that is treated by the application launcher (openapp in
> GNUstep) as applications. In GNUstep terminology, a "flattened"
> layout, such as used in Debian, makes the application bundles
> platform-specific. In an unflattened layout, however, such as used by
> default when using the GNUstep layout (as opposed to the FHS layout
> that we are constrained to use in Fedora), fat binaries are possible:
> binaries are stored under a directory specifying their platform.
> 
> for instance:
> 
> Hello.app
> \--- i386
> |       \--- hello
> \--- x86_64
>         \--- hello
> 
> This seems more desirable, in that it will allow an unmodified
> 'openapp' launcher to work on multilib systems: the default
> application path is /usr/lib/GNUstep/Applications, regardless of
> whether %{_libdir} is /usr/lib or /usr/lib64.

Please note that the unflattened layout is not just for different
archs, but even different compilers/libcombos. In a flattened world
one can only support one combo which for example will make
opengroupware conflict with other GNUstep apps.

At least this is my understanding, I don't know how Debian has solved
this, or even if opengroupware is part of Debian, so perhaps they
haven't seen the issue, yet.

> The problem, right now, is that GNUstep tools are currently installed
> in /usr/bin/<arch>. Which conflicts with util-linux-ng, where
> /usr/bin/<arch> is an executable wrapper around 'setarch <arch>'.

What if we simply crop off the <arch> from the path? Would that make
us fully FHS compliant again?

> We would need to settle on our GNUstep layout, before the rest of
> GNUstep can be packaged. The main options right now seem to be:
> - FHS, flattened (like Debian). We would need to override GNUstep-make
> to install under %{_libdir} rather than %{_prefix}/lib. It will
> require a customized openapp to handle multilib systems
> 
> - FHS, unflattened (like our current gnustep-make). Works well with
> multilib. We need to decide where to put GNUstep tools: Axel suggests
> /usr/bin/GNUstep/<arch>.

Actually I suggested putting them under %{_libexecdir} with
symlinks/wrappers back to %{_bindir}. I don't think that a
subdirectory under %{_bindir} is really in FHS/Fedora spirit.

But now I think maybe we need to place them directly under %{_bindir}
and let rpm deal with the different archs as it does for all other
%{_bindir} mixing of subarchs with colors etc.

> Base libraries currently go in /usr/lib/<arch>, and are probably
> fine there.

Shouldn't this at least go beneath %{_libdir} instead of /usr/lib?

> Moving them to /usr/lib/GNUstep/<arch> might cause confusion as the
> higher-level frameworks are installed there.
> 
> - Pure GNUstep layout. Everything goes in /usr/GNUstep

Thanks for the writeup and if smeone is interested: Some discussion in
context of a bug report happened here:

https://bugzilla.redhat.com/show_bug.cgi?id=437551

I think Fedora's typical way of dealing with this is the following:

o multiarch/multilib binaries are not supported, e.g. all other
  instances either hide non consumer binaries under %{_libdir}, or
  allow x86_64 to overwrite less colorful cousins like i386.

o libraries need to be placed under %{_libdir}.

> Thoughts? Once we come up with a consensus I'll probably start a
> page on the Wiki. Anyone interested in joining a GNUstep SIG?

I think it is important for many GNUstep app builders to voice in
their experiences with the GNUstep build procedure and see how we can
make sure the layout we will be "setting in stone" by approval by the
FPC will be pleasing all.

A wiki page will be great as we can even ask non Fedorians like the
opengroupware people to have a look and see whether it would fit their
software's need.
-- 
Axel.Thimm at ATrpms.net
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