Rawhide changes coming [LWN.net]

The Fedora "no frozen Rawhide" scheme is about to go into operation. That means there will be two independent development repositories in operation: one will be frozen for the Fedora 13 release, while the other continues to offer the full Rawhide experience with new and scary packages. Rawhide users will want to look at their repository configurations to be sure they're tracking the version they want.

There are also changes to library linking going into Rawhide which could create minor problems for people building packages. There is some concern about the timing of this change (right before the F13 freeze), but the change is going forward regardless; more information can be found on this page.

Rawhide changes coming

Posted Feb 10, 2010 19:54 UTC (Wed) by MisterIO (guest, #36192) [Link] (1 responses)

> "Rawhide users will want to look at their repository configurations to be sure they're tracking the version they want."

And how do I know if I'm tracking the version I want?

Rawhide changes coming

Posted Feb 10, 2010 19:55 UTC (Wed) by MisterIO (guest, #36192) [Link]

Sorry, I'm an idiot. I've just found the answer to that.

Rawhide changes coming

Posted Feb 10, 2010 20:49 UTC (Wed) by nix (subscriber, #2304) [Link] (7 responses)

The library linking changes don't appear to be in upstream ld yet, which
is a shame because they look really nice (though they are disruptive in
the short term, nonetheless everything they break is already buggy and
only working by chance as it is).

Rawhide changes coming

Posted Feb 10, 2010 22:50 UTC (Wed) by mjw (subscriber, #16740) [Link] (2 responses)

The more exact library linking changes are required when using the new GNU gold linker (also in upstream binutils). So this change will make a future switch to gold as default linker easier. Which would be nice because gold seems a lot faster: http://lwn.net/Articles/274859/

Rawhide changes coming

Posted Feb 11, 2010 1:22 UTC (Thu) by nix (subscriber, #2304) [Link] (1 responses)

Oh yes, I agree it's a good thing and so forth. I'm just irritated that
this isn't upstream so non-Fedora users can't benefit yet :) what, me,
impatient?

Rawhide changes coming

Posted Feb 12, 2010 16:04 UTC (Fri) by nix (subscriber, #2304) [Link]

Er, actually it's been upstream for ages, as --no-add-needed: I don't know why my initial greps didn't find it. (However, it looks like it shouldn't be used in anger until its behaviour with regard to weak symbols is fixed, unless you like having nonthreaded C++ programs fail to link for no good reason. It doesn't look like that's been fixed yet...)

Rawhide changes coming

Posted Feb 11, 2010 17:43 UTC (Thu) by proski (guest, #104) [Link] (3 responses)

I never liked the permissiveness of dynamic linking for another reason. It would break when linking statically. Thus, developers using shared libraries would be at disadvantage because they would not see a potential problem with users using static libraries (which is not uncommon for embedded systems and for emergency system utilities).

Fedora is confirming its reputation as the best distro for software developers.

Rawhide changes coming

Posted Feb 12, 2010 0:02 UTC (Fri) by nix (subscriber, #2304) [Link] (2 responses)

Well, this doesn't change that. The dynamic linker still does dependency
chasing: if linking dynamically to library A that uses library B, you only
need to mention library A. Static links need to mention both libraries.
(This, and support for nasty systems whose dynamic linker doesn't do
dependency chasing either, is the entire raison d'etre of libtool .la
files. This makes them pretty useless on dynamically-linked Linux systems,
so most distros drop them.)

Rawhide changes coming

Posted Feb 12, 2010 18:40 UTC (Fri) by Wol (subscriber, #4433) [Link] (1 responses)

The linker I used to use (Fortran / Primos) when doing static linking would copy all the required modules from the library to the executable - using it as a library in the "real" sense :-)

So if you loaded a module from library A that needed a module from library B, then the linker would complain with "unsatisfied reference" if you tried to save and quit without linking B.

Cheers,
Wol

Rawhide changes coming

Posted Feb 12, 2010 21:50 UTC (Fri) by nix (subscriber, #2304) [Link]

The rationale for the design decisions in ELF was also that you could
treat shared libraries just like .a libraries, and they'd work: hence
things like symbol interposition, which seem mad until you realise that
this is exactly how static libraries used to work (first symbol wins).

Rawhide changes coming

Posted Feb 11, 2010 2:14 UTC (Thu) by pabs (subscriber, #43278) [Link]

This no frozen rawhide thing sounds like it turns Fedora into something more like Debian, where rawhide = experimental, except experimental isn't a full distribution in its own right.

The DSO change looks like a good idea. Hopefully Debian's symbol tracking dpkg-shlibdeps will have put us in a good position for when this change is accepted upstream.

There are quite a few packages that still FTBFS with binutils-gold in Debian or will be affected by the DSO change (as detected by dpkg-shlibdeps), so it seems lots of packages relied on this misbehaviour of the runtime linker:

http://bugs.debian.org/cgi-bin/pkgreport.cgi?users=peter....

A proportion of the bugs are fixed in Debian, so Fedora and upstream folks might like to check out our patch tracker in case some maintainers haven't forwarded patches upstream:

http://patch-tracker.debian.org/

Rawhide changes coming

Posted Feb 11, 2010 8:23 UTC (Thu) by freggy (guest, #37477) [Link] (1 responses)

Those library linking changes look similar to the --as-needed --no-undefined ldflags, which are already used for some time by Mandriva. Is there any difference?

http://wiki.mandriva.com/en/Overlinking
http://wiki.mandriva.com/en/Underlinking

Rawhide changes coming

Posted Feb 11, 2010 9:05 UTC (Thu) by rahulsundaram (subscriber, #21946) [Link]

Its not the same thing at all

http://lists.fedoraproject.org/pipermail/devel/2010-Janua...