Re: [gentoo-user] Re: Updating libpng: another lib tool cockup?

[Michael Schreckenbauer]

On Monday, 19. September 2011 10:58:52 Allan Gottlieb wrote:
> On Mon, Sep 19 2011, Michael Schreckenbauer wrote:
> > On Monday, 19. September 2011 10:20:25 Allan Gottlieb wrote:
> >> On Mon, Sep 19 2011, Alan McKinnon wrote:
> >> >> > revdep-rebuild checks everything, revdep-rebuild --library
> >> >> > checks just some things.
> >> >> >
> >> >> > ebuilds sometimes issue messages to check just the libraries
> >> >> > known
> >> >> > to have been updated, but a full revdep-rebuild after an
> >> >> > update
> >> >> > will catch those anyway.
> >> >>
> >> >> Until recently I skipped the "--library" step exactly because I
> >> >> knew
> >> >> revdep-rebuild will find and fix the broken packages after I
> >> >> delete
> >> >> the old library.  So, why bother with the --library step, right?
> >> >>
> >> >> However.  A few weeks ago I got caught when I deleted one of
> >> >> those
> >> >> obsolete libraries and only then did I find out that gcc is one
> >> >> of
> >> >> the packages that depend on it :(
> >> >>
> >> >> I don't skip the --library step any more.
> >> >
> >> > That's odd behaviour, I wonder what caused the difference.
> >> >
> >> > Surely revdep-rebuild itself can't do this different just because
> >> > you
> >> > specified a library to compare? I wonder if that lib was maybe in
> >> > the
> >> > revdep-rebuild exclude list.
> >> >
> >> > I'd be interested to track it down for reference, do you remember
> >> > the
> >> > library involved?
> >>
> >> It occurs exactly in the case we are discussing libpng
> >>
> >> ajglap gottlieb # revdep-rebuild; revdep-rebuild --library
> >> '/usr/lib64/libpng14.so.14' * Configuring search environment for
> >> revdep-rebuild
> >>
> >>  * Checking reverse dependencies
> >>  * Packages containing binaries and libraries broken by a package
> >>  update
> >>  * will be emerged.
> >>
> >> ...
> >>
> >>  * Checking reverse dependencies
> >>  * Packages containing binaries and libraries using
> >>
> >> /usr/lib64/libpng14.so.14 * will be emerged.
> >
> > First one emerges *broken* packages.
> > Second one emerge packages *using* png14 (not necessarily broken)
>
> OK.  But the claim was that: if
>    revdep-rebuild
> with no argument found nothing to build, then
>    revdep-rebuild --library <some-library>
> will find nothing.

This is not true.
revdep-rebuild without --library argument checks for packages with *broken* 
linking, eg a library changed it's name and the original one was removed by an 
update.
revdep-rebuild --library checks for packages using that library.

If the first one returns nothing, that means, your linking is all ok.
If the second one returns nothing, it tells you, that nothing is using that 
library at all.

> This guarantee is apparently no long true as my example in another msg
> illustrated.

I doubt it was true in the past.

Best,
Michael