Apply for the Google Summer of Code at Debian even if you are already a Debian Developer!

The Debian GSOC admins have made it clear that it is possible for DDs to be selected as GSOC students (even if people who are not Debian contributors will be prioritized). So, if you are a student, a Debian Developer, and interested in getting paid to work on Debian during the summer, it’s a very good idea to apply! For the details, see this blog post.

Note: the goal of this post is not to start a flamewar, but to make sure that everybody is fully aware of the unrestricted selection process. Since we are going to accept DDs as students anyway, let’s at least try to get the best applications.

Debian’s KVM + Ubuntu karmic => bug?

I’ve been playing with virtualization, and KVM in particular. However, I’m running into an interesting problem. Below is how Ubuntu Netbook Remix look inside my KVM (either using virt-viewer, virt-manager or directly KVM to display the VM). Note how the top panel is fine. I’m using KVM 88 from experimental (but I had the same problem with KVM 85 from unstable), the cirrus video driver inside the VM, and an up-to-date karmic VM.
Has someone ran into that problem already? If yes, where is it tracked? I’m been failing to find the correct search keywords so far.


PTS as a great tool for upstream developers

I recently realized how nice the Packages Tracking System is for upstream developers who want to follow the status of their software in Debian. By subscribing, they can easily monitor (and reply to) bug reports, and the general status of their software in Debian. I’m trying to help with coreutils maintainance, and it’s great to see upstream developers answer directly to bug reporters on Debian.

So, maintainers, tell your upstreams about the PTS! ;)

It might be a good idea to actually mention that use case on obvious places (not sure what the obvious places are, though).

mailing list for cross-distributions collaboration

A few months ago, I asked a set of questions on development mailing lists of a few GNU/Linux distributions. This resulted in very interesting discussions. As promised back then, all the answers from all distros I contacted can be read on the web or as an mbox file.

Also, kindly agreed to host a mailing list to ease discussions between distributions, and act as a central point of contact. You can subscribe, and post to distributions at lists dot freedesktop dot org.

This mailing list is for people involved (or interested) in the development of distributions. Questions that are on-topic are both technical and social/organizational issues, like:

  • How do you achieve graphical boot in your distro? Do you use some kind of dependancy-based or events-based boot?
  • How do you package both ruby 1.8, ruby 1.9 and jruby, or handle KDE vs KDE4?
  • Do you use a system that gives a limited set of rights to new contributors?

Off-topic stuff obviously include trolling about which distribution is the best one, or user support.

Don’t hesitate to forward this announcement to all interested parties. Let’s make this mailing list something useful together!

Also, I really apologize for procastinating announcing this list for sooo long. I’m really good at procastinating interesting stuff, it seems.

dd + /dev/random fun

From Adrien Lebre, who seems to be having fun working on kDFS:

$ dd if=/dev/random of=file bs=1024 count=2
0+2 records in
0+2 records out
256 bytes (256 B) copied, 0.000705717 s, 363 kB/s
$ ls -l file
-rw-r--r-- 1 lucas lucas 256 2008-02-08 17:53 file

Can be easily explained using strace:

open("/dev/random", O_RDONLY|O_LARGEFILE) = 0
open("file", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 1
read(0, "p(\361\241,\360-\330~M\245y\10=\274U\201c\207\v\336a\273"..., 1024) = 128
write(1, "p(\361\241,\360-\330~M\245y\10=\274U\201c\207\v\336a\273"..., 128) = 128
read(0, "\362,LW5l.?\242\22\252\223\206\375\10\326\335\316\374\372"..., 1024) = 128
write(1, "\362,LW5l.?\242\22\252\223\206\375\10\326\335\316\374\372"..., 128) = 128
close(0)                                = 0
close(1)                                = 0

Re: a problem with tools

Joey has a problem with tools used over dpkg-dev’s core tools to help maintainers maintain their debian packages.

I was wondering about the adoption of those tools, so I simply grepped the logs from my last rebuild for “^Setting up $TOOL “, which is more accurate than looking at build-deps, since someteam-pkg-tools could depend on cdbs, and hide cdbs usage.

Results, with lists of packages “affected”:

Tool Packages
debhelper 11434 (95.8%)
cdbs 2665 (22.3%)
dpatch 1714 (14.4%)
quilt 935 (7.8%)
dbs 57 (0.47%)
yada 32 (0.27%)
debmake 2 (0.017%)

(if you want me to check the logs for another tool, just tell me)

My personal opinion on this is that tools that make sense are slowly getting adopted (that probably includes debhelper, cdbs, dpatch and quilt). The main difference between debhelper and the other tools is that the other tools don’t try to solve a problem for everybody. cdbs perfectly makes sense for some packages: the simple ones, where you only have to modify 4-5 lines in the output from dh_make to build properly.

Patch systems are also a good way to track changes made to upstream source, and probably encourage giving back patches to upstream. Note that my stats don’t include packages using cdbs’ simple-patchsys, so there are probably really close to 1/4 or 1/3 of our packages using some sort of patch system. How course, having simple-patchsys, dpatch and quilt sounds a bit stupid. But last time I checked, nobody took the time to blog a comparison of those tools, saying why {quilt,dpatch} is better than {simple-patchsys,dpatch,quilt}. Also, simple-patchsys probably makes a good-enough job for its users, so they don’t see the point in changing.

Of course, it’s easier to bury your head in the sand, and ignore the fact that those tools solve real problems for so many people and packages, and make their lives easier. :-)

Fixing build failures with dash is cool.

The bad thing with fixing build failures with dash is that there are still a lot of open bugs. (Remember, the 0-day NMU policy applies to those, so it’s a good opportunity to improve your NMU karma. And I will sponsor your NMUs if you can’t upload!).

The good thing is that you sometimes run into funny code, like:
    pushd docs ; $(MAKE) distclean || true ; popd

Since pushd/popd is a bashism, the Ubuntu patch changed this to:
    cd docs ; $(MAKE) distclean || true ; cd $(CURDIR)

Which works, but is … interesting? :-)

Help us get rid of dash build failures in Debian!

Following my rebuild of all packages using /bin/dash as /bin/sh, we now have a nice list of bugs.

Those bugs are cool:

  • The relaxed NMU rules apply to them, since they are part of the dash release goal. Which means that they can all be fixed using 0-day NMUs.
  • Most of them are really easy to fix. (for many of them, a patch is already provided by Ubuntu)

So, if you want to get involved in Debian development, try to submit NMU patches for those bugs. If you want me to sponsor the upload, please Cc me when you submit the patch.

And even if you don’t care about Debian, but only about Ubuntu (which is fondamentally wrong, as everybody knows that Ubuntu is based on Debian), fixing these bugs also helps Ubuntu a lot: all those bugs hurt Ubuntu, since Ubuntu uses dash as /bin/sh by default, and, even if the packages in Ubuntu have been patched, it’s still causing additional work every time a new package is uploaded to Debian, and has to imported in Ubuntu.

If you have questions with the process, please ask them using the comments below.

I use the following process on those bugs, and it’s probably a good idea that you do the same if you intent to submit patches:

  • build the package with a chroot using bash
  • build the package with a chroot using dash (you can just use a different pbuilder tarball for that). Check that the problem can be reproduced.
  • fix the package
  • build the new package with a chroot using bash
  • build the new package with a chroot using dash
  • compare the built packages using debdiff for old_package_using_bash, new_package_using_bash, and new_package_using_dash. If the content doesn’t match, we have a problem.

If you submit NMU patches, please also have a look at the other bugs in the package, or at the lintian output. I don’t mind sponsoring small fixes for non-cosmetic/non-wishlist stuff at the same time.

Rebuilding the archive with dash as /bin/sh

I rebuilt all Debian packages twice. The first time with bash as /bin/sh, and the second time with dash as /bin/sh.

About 120 packages built fine with bash, but failed to build with dash. I filed all the bugs that weren’t filed already.

Then I debdiff’d the resulting binary packages, and found about 40 packages that built fine with bash and dash, but produced different binary packages (mostly files missing/being added)!

All the bugs (including those that were already filed) have been usertagged. Most of those bugs are quite easy to reproduce and fix, so, if you are bored, send patches!

I was a bit surprised by the high number of problems I found, since Ubuntu has been using dash as /bin/sh for more than a year, even on their buildds. Some packages have been fixed in Ubuntu, but the Debian maintainers didn’t include the fix. But many packages were simply broken in Ubuntu.

Now I’ll try to find time to work on the Build Daemon From Hell idea, and on rebuilds inside qemu.

Ubuntu giving back to Debian: facts and numbers!

I’ve always been annoyed by the discussions about “is Ubuntu really giving back to Debian?”. Debian Developers usually don’t see a lot of “giving back”, and Ubuntu Developers complain about Debian Developers ignoring their bug reports and patches.

So, a few months ago, I proposed that Ubuntu developers use a usertag when they report bugs to the Debian BTS, so they can be tracked.

Results are available:


  • It’s really good to see Ubuntu developers reporting bugs and contributing patches to Debian!
  • … But more bugs (and patches) would be better, of course. Let’s continue the good work!
  • Many patches are applied very fast in Debian (as usual), but in some cases, the patches are ignored (as usual, too). It would be great if Debian Developers could treat those bugs as higher priority, since it makes life easier on the Ubuntu side (less difference means less work)

If you are an Ubuntu Developer, read wiki.u.c/Bugs/Debian/Usertagging for the details on how to tag the bugs you file. Note that the submittodebian script in the ubuntu-dev-tools package already sets the usertags.