Re: [gentoo-science] sage-4.3.5-r1 && sage-core

[Christopher Schwan <cschwan@students.uni-mainz.de>]

On Monday 19 April 2010 05:18:21 François Bissey wrote:
> > Hi Steve,
> > 
> > On Sunday 18 April 2010 21:10:17 Steven Trogdon wrote:
> > > Christopher,
> > > 
> > > 
> > > 
> > > I've finally gotten around to trying the changes and a clean emerge of
> > > everything installs as it should. Here a revdep-rebuild reveals that
> > > libsingular.so can't be found. The proposed resolution is to re-emerge
> > > sage-core which, of course, doesn't resolve the issue. What's the
> > > procedure to update the ld cache when libraries like libsingular.so are
> > > not in the "standard" location? Should something be done in
> > > sage-singular that doesn't compromise things?
> > 
> > I noticed the same behavior and looked at /etc/ld.so.cache which pointed
> > to  /etc/env.d/... - so the gentoo way of doing this would be to add a
> > file which contains LDPATH="/opt/sage/local/lib". Though I did not test
> > it, it should work and I will add this file tomorrow.
> 
> Hi guys,
> 
> I don't like that solution at all. What will happen if you have system wide
> singular and sage-singular?
> If you add this file there is a good  chance that someone wanting to use
> the system provided singular will end up using sage-singular.

Yes, thats right! - I did not think of that.

> 
> Just for the purpose of testing for side effects, I installed
> singular-3.1.1. revdep-rebuild didn't pick up on sage-core after that.
> Probably because libsingular lacks an soname and is completely
> unversioned.
> 
> No. sage-env takes care of telling sage where to look. There is no real
> perfect solution so long as we have ship sage-singular.
> For now I would put a file in /etc/revdep-rebuild masking the offending
> libraries.
> 50sage-core:
> #Those files look for a version of libsingular that will be located through
> # LD_LIBRARY_PATH at run-time.
> LD_LIBRARY_MASK="lib1.so lib2.so lib3.so"

Another option (read: hack) would be to create a separate directory containing 
a symlink to libsingular.so (this is the only library which is reported by 
revdep-rebuild) and to point revdep-rebuild to this directory. Of course, this 
is not the best way of getting rid of this error.

In my opinion, the best "solution" would be to print out a warning/info after 
installing sage-core which basically says revdep-rebuild reports false 
positives and just wait for the Sage people upgrading to a new release of 
Singular (see http://trac.sagemath.org/sage_trac/ticket/8059 and 
http://trac.sagemath.org/sage_trac/ticket/8228).

> 
> -----
> Of course that means that revdep-rebuild cannot pick up the fact that
> they are broken. Which of course it may not be able to do anyway because
> of the lack of versioning.
> On the positive side a change in sage-singular will always coincide with
> a change of sage-core so there shouldn't be any trouble.
> 
> Francois

Christopher