Broken app-office/libreoffice binary packages generated (NOT app-office/libreoffice-bin)

I'm posting this here because a new LibreOffice version was stabilized two days ago, and at the same time a hidden bug crept in...

Because of an unintended interaction between a python-related eclass and the app-office/libreoffice ebuilds (any version), merging recently self-generated (see below for exact timeframe) libreoffice binary packages can fail to install with the error

* ERROR: app-office/libreoffice-4.3.5.2::gentoo failed (setup phase):
* PYTHON_CFLAGS is invalid for python-r1 suite, please take a look @ https://wiki.gentoo.org/wiki/Project:Python/Python.eclass_conversion#PYTHON_CFLAGS 

The problem is fixed now, but any libreoffice binary packages generated with a portage tree from Fri Jan 2 00:15:15 2015 UTC to Sun Jan 4 22:18:12 2015 UTC will fail to reinstall. Current recommendation is to delete the self-generated binary package and re-install libreoffice from sources (or use libreoffice-bin).

This does NOT affect app-office/libreoffice-bin.

Updates may be posted here or on bug 534726. Happy heating. At least it's winter.

Testers needed for dev-lang/perl-5.20.1-r4 (stabilization candidate)

Most of us in the Gentoo Perl packaging team are already running ~arch Perl even on otherwise stable machines, and Perl 5.20 is looking very good so far. Our current plan is to wait for another month or similar and file the stabilization request for it in February. This would be a real achievement, since we'd at that time actually have the latest and greatest upstream stable Perl release also stable in Gentoo; this hasn't been the case for a very long time.
Of course, we need testers for that; the architecture teams cannot possibly try out all Perl programs in Gentoo with the new version. So, if you're feeling adventurous, and if you are running a fully updated stable system, please help us!
What do you need to do? First, upgrade perl-cleaner to ~arch by placing the following line in your package.keywords (or package.accept_keywords)

app-admin/perl-cleaner

and updating perl-cleaner (to currently 2.19):

emerge -u1a perl-cleaner

Then, upgrade Perl (and only Perl) to ~arch by placing the following exact three lines in your package.keywords (or package.accept_keywords):

dev-lang/perl
virtual/perl-*
perl-core/*

Then, upgrade your system with

emerge -uDNav world
perl-cleaner --all

This should now already be much easier than with previous Perl versions. In theory, all Perl packages should be rebuilt by emerge via the subslot rebuild mechanism, and perl-cleaner should not find anything to do anymore, but we cannot be 100% sure of that yet so far. (Looking forward to feedback.)
Well, and then use Perl and use your system, and if you encounter any problems, file bugs!!!

A final remark, once Perl 5.20 becomes stable you may want to remove above keywording lines from your portage configuration again.

Gentoo mailing lists down

Since yesterday the host running all Gentoo mailing lists is down. So far there is no information yet available on the nature of the problem. Please check the Gentoo Infrastructure status page, http://infra-status.gentoo.org/, for updates.

[Edit: All fixed.]

This public service announcement has been brought to you by non-infra Andreas.

RDepending on Perl itself

Writing correct dependency specifications is an art in itself. So, here's a small guide for Gentoo developers how to specify runtime dependencies on dev-lang/perl. First, the general rule.
Check the following two things: 1) is your package linking anywhere to libperl.so, 2) is your package installing any Perl modules into Perl's vendor directory (e.g., /usr/lib64/perl5/vendor_perl/5.20.1/)? If at least one of these two questions is answered with yes, you need in your dependency string a slot operator, i.e. "dev-lang/perl:=" Obviously, your ebuild will have to be EAPI=5 for that. If neither 1) nor 2) are the case, "dev-lang/perl" is enough.
Now, with eclasses. If you use perl-module.eclass or perl-app.eclass, two variables control automatic adding of dependencies. GENTOO_DEPEND_ON_PERL sets whether the eclass automatically adds a dependency on Perl, and defaults to yes in both cases. GENTOO_DEPEND_ON_PERL_SUBSLOT controls whether the slot operator ":=" is used. It defaults to yes in perl-module.eclass and to no in perl-app.eclass. (This is actually the only difference between the eclasses.) The idea behind that is that a Perl module package always installs modules into vendor_dir, while an application can have its own separate installation path for its modules or not install any modules at all.
In many cases, if a package installs Perl modules you'll need Perl at build time as well since the module build system is written in Perl. If a package links to Perl, that is obviously needed at build time too.

So, summarizing:

eclass	1) or 2) true	1) false, 2) false
none	"dev-lang/perl:=" needed in RDEPEND and most likely also DEPEND	"dev-lang/perl" needed in RDEPEND, maybe also in DEPEND
perl-module.eclass	no need to do anything	GENTOO_DEPEND_ON_PERL_SUBSLOT=no possible before inherit
perl-app.eclass	GENTOO_DEPEND_ON_PERL_SUBSLOT=yes needed before inherit	no need to do anything

NJP accepted: Thermally induced subgap features in the cotunneling spectroscopy of a carbon nanotube

Today's good news is that our manuscript "Thermally induced subgap features in the cotunneling spectroscopy of a carbon nanotube" has been accepted for publication by New Journal of Physics.
In a way, this work is directly building on our previous publication on thermally induced quasiparticles in niobium-carbon nanotube hybrid systes. As a contribution mainly from our theory colleagues, now the modelling of transport processes is enhanced and extended to cotunneling processes within Coulomb blockade. A generalized master equation based on the reduced density matrix approach in the charge conserved regime is derived, applicable to any strength of the intradot interaction and to finite values of the superconducting gap.
We show both theoretically and experimentally that also in cotunneling spectroscopy distinct thermal "replica lines" due to the finite quasiparticle occupation of the superconductor occur at higher temperature T~1K: the now possible transport processes lead to additional conductance both at zero bias and at finite voltage corresponding to an excitation energy; experiment and theoretical result match very well.

"Thermally induced subgap features in the cotunneling spectroscopy of a carbon nanotube"
S. Ratz, A. Donarini, D. Steininger, T. Geiger, A. Kumar, A. K. Hüttel, Ch. Strunk, and M. Grifoni
New J. Phys. 16, 123040 (2014), arXiv:1408.5000 (PDF)

How do I run ~arch Perl on a stable Gentoo system?

Here's a small piece of advice for all who want to upgrade their Perl to the very newest available, but still keep running an otherwise stable Gentoo installation: These three lines are exactly what needs to go into /etc/portage/package.keywords:

dev-lang/perl
virtual/perl-*
perl-core/*

Of course, as always, bugs may be present; what you get as Perl installation is called unstable or testing for a reason. We're looking forward to your reports on our bugzilla.

EAPI=5 adoption has reached 50% of ebuilds in the portage tree

As of today, more than 50% of the 37527 ebuilds in the Gentoo portage tree use the newest ebuild API (EAPI) version, EAPI=5!
The details of the various EAPIs can be found in the package manager specification (PMS); the most notable new feature of EAPI 5, which has sped up acceptance a lot is the introduction of so-called subslots. A package A can specify a subslot, another package B that depends on it can specify that it needs to be rebuilt when the subslot of A changes. This leads to much more elegant solutions for many of the the link or installation path problems that revdep-rebuild, emerge @preserved-rebuild, or e.g. perl-cleaner try to solve... Another useful new feature in EAPI=5 is the masking of use-flags specifically for stable-marked ebuilds.
You can follow the adoption of EAPIs in the portage tree on an automatically updated graph page.