F21 System Wide Change: lbzip2 as default bzip2 implementation

[Mikolaj Izdebski]

> > ** possibly adjust spec files to require or build-require lbzip2 instead of
> > bzip2.
> Is this necessary? Wouldn't it be better to have lbzip2 Provide bzip2
> or something so that updating all those packages is not necessary,
> and also that people who prefer normal bzip2 can still use it?

You could do that, but then two packages would have the same virtual
provide and it wouldn't be well defined which one would be installed.
In such cases YUM seems to choose packages with shorter names, so it
would prefer bzip2 over lbzip2.  At least one package somewhere
low in the system has to require lbzip2 explicitly.

I think that package maintainers who want to use lbzip2 should declare
it as explicit dependency.  Assuming that packages are calling standard
bzip2 command names (bzip2, bzcat and so on) users will still be able
to switch implementations as they want by configuring alternatives,
even if package has requires on lbzip2.

We don't need to migrate all packages to Require lbzip2.  If lbzip2 has
highest priority in alternatives then it will be used as long as it is
installed.  It doesn't even need to Provide bzip2.  It should be enough
to include lbzip2 in minimal installation and add is a dependency of
@buildsys-build to effectively make it default implementation.

--
Mikolaj Izdebski