apt-get install debian-wizard

Contribute to Debian while promoting the Debian Administrator’s Handbook

September 27, 2011 by Raphaël Hertzog

We just announced the launch of the fundraising campaign for the Debian Administrator’s Handbook.

We wanted to use this opportunity to let people contribute money both to our project but also to Debian itself. That’s why we have setup a special link that you can use to participate. 15% of any donation made through this link (after VAT has been subtracted) will be given back to the Debian Project.

Here’s the link: https://debian-handbook.info/go/ulule-debian/

Feel free to use this link when promoting the project to your friends, so that even more money goes back to Debian.

You can also embed a special widget on your website where any visitor that ends up becoming a supporter will also contribute 15% to the Debian project.

Help us spread the word about the project, and help raise money for Debian!

Do You Want a Free Debian Book? Read This.

September 27, 2011 by Raphaël Hertzog

A bit more than a year elapsed since we announced our plans to translate our Debian book into English and to try to get it published under a license compatible with the Debian Free Software Guidelines. But we’re now ready to go to the next step.

Completing the translation of 450 pages book is a huge work, we estimate it’s going to take roughly 3 full time months for both Roland and me. Since we’re freelancers, we can take the required time provided that we have a minimum income during that period. That’s where you come into play: we have setup a crowdfunding campaign on Ulule.com and we need your support to raise €15000 (this is the absolute minimum for us to be able to commit the required time).

Even if a good and up-to-date book on Debian is a great perspective, we want to go further than that by adding the perspective of getting a DFSG-free Debian book. That’s why we have transformed the crowfunding campaign in a liberation campaign. When you support the project, you can pledge money towards a liberation fund… and if this fund reaches €25000 then the book will be published under the GPL-2+ and CC-BY-SA 3.0 licenses.

On top of this, when you support this project you can select a reward that goes from a copy of the ebook to a dinner with the authors (only 10 places for the latter)! Among the other rewards, there’s obviously a paperback version of the book, but also an individual one-hour mentoring session with me… a nice way to get you hooked as a new Debian contributor (limited to 40 persons, don’t miss the opportunity!).

Wait no longer, click here and pledge some money to bring this reference book to Debian and the rest of the world.

We also need your help to spread the news and get as many supporters as possible. Share the link with your friends, write an article on your blog, put a widget on your website, etc. Thank you very much!

Click here to go to the fundraising page and to learn more about this project.

How to triage bugs in the Debian bug tracking system

September 16, 2011 by Raphaël Hertzog

Triaging bugs is one of the easiest way to start contributing to Debian. I’ll teach you the basics in this article.

1. Prerequisites

All interactions with the Debian Bug Tracking System (BTS) happen through email so you need to have an email account with an address that you’re willing to make public.

All the mail that you send to the BTS will be archived and publicly available through its web-interface. This also means that you should have some spam filters in place because it will inevitably be harvested by spammers. 🙁

To ensure that this email address is consistently used by the various tools that we’re going to use, it’s a good idea to put this email address in the DEBEMAIL environment variable. You can also specify your full name in DEBFULLNAME (in case you don’t want to use the name associated with your Unix account). You usually do this by modifying ~/.bashrc (if you use bash as login shell):

export DEBEMAIL="hertzog@debian.org"
export DEBFULLNAME="Raphaël Hertzog"

You should also install the devscripts package, it provides the bts command that we’re going to use.

2. Find a package or a team with too many bugs

You can literally pick any popular software that’s in Debian, they almost always get more bug reports than the maintainers can handle. Instead of picking a package, you can also select a packaging team and concentrate your efforts on the set of packages managed by the team.

In any case, it’s important to receive the bug traffic for the packages that you’re going to work on. If you went for a specific package, you should subscribe to the package via the Package Tracking System (there’s a subscribe box on the bottom left corner once you selected the source package of interest). If you decided to help a team, there’s usually a dedicated mailing list receiving all bug traffic.

You can browse a list of packages with the most bugs if you have troubles finding a package to work on.

A stack of bug reports to triage

3. Triage bugs!

Bug triaging is all about making sure that bugs are correctly classified so that when a developer looks at the bug list, he can quickly find bugs with all the information required to be able to fix them!

3.1 Adding information to bug

Adding supplementary information is easily done just by sending a mail to XXXX@bugs.debian.org (replace XXXX with the bug number).

But often you want to reply to a message in the bug history, in that case “bts --mbox show XXXX” is for you. It will grab the corresponding mailbox and open a mailer (mutt by default) on it. Now you can directly reply in your favorite mailer.

3.2 Classifying bugs

The Debian BTS uses tags (click the link and read the doc!) to classify bugs. “bts tag XXXX + foo” will add the foo tag (replace the + with a – to remove a tag). If you want to explain why you’re adding a tag, you should instead reply in the bug log as explained above, put control@bugs.debian.org in Bcc (Blind Carbon Copy) and start the body of your message with your tag command:

tag XXXX + foo
thanks

But what tag should you add? When a bug is submitted, you should try to reproduce the bug. If you can reproduce it, then tag the bug “confirmed” (example in #641710). If you can’t, you should request more information (ex: a sample document triggering the bug, a configuration file, the output of some relevant command, etc.) until you can reproduce it or conclude that it was a user mistake. When you request supplementary information due to this, you should tag the bug “unreproducible moreinfo” (example in #526774). “moreinfo” should be later dropped when the requested information are provided, and “unreproducible” should be dropped if those information were enough to actually help reproduce the bug (example in #526774).

During that initial evaluation, it’s also worth differentiating packaging bugs (which are specific to Debian) from upstream bugs (which are relevant also for non-Debian users). The latter should be tagged “upstream” (and forwarded upstream if the bug is reproducible or contains enough information for the upstream developers, example in #635112).

If you saw a (viable) patch in the bug log, the bug should be tagged “patch”. This is usually done by the patch submitter but sometimes it’s forgotten (example in #632460). Take care though to not reinstate the patch tag if it was initially set but then dropped by the package maintainer after a review of the patch.

If the title of the bug report is not descriptive enough, you can change it with a “retitle XXXX new-title” command (example in #170850).

You can also change the severity of the bug report depending on the impact of the problem (with a command “severity XXXX new-severity”, what a surprise!). Request for new features are “wishlist”, most documentation problems are “minor”. On the other side of the scale, you can use “important” for bugs that are very annoying but that should not block a release. “serious”, “grave” and “critical” are used for release critical bugs, check the official definitions of the severities (examples in 502738 or #506498).

3.3 Closing non-bugs and bugs that are already fixed

If your analysis of the bug report is that it’s not really a bug but a user mistake, then you should close it by sending a mail to XXXX-done@bugs.debian.org with some explanations of the user’s mistake so that he can get past his problem (example in #592853).

If the problem was a real bug, but one that is apparently already fixed, you should try to quickly find the version that fixed the bug. If you can’t find it in the changelog (there’s a link to it in the PTS, or you can use /usr/share/doc/package/changelog.Debian.gz), you’ll make the safe assumption that the upstream version you’re currently using is the first one where this is fixed. Then you send a mail to XXXX-done@bugs.debian.org but you start your mail with “Version: version-that-fixed-the-bug” and continue with a small explanation of why you believe the bug to be fixed by this version (example in #122948).

3.4 Reassigning misfiled bug reports

Bug reports are not always filed against the proper package. Users file bugs against applications where they experience the bugs, but the real bug might be in an underlying library or application.

When that happens, you should use the “reassign XXXX correct-package version” command to get it filed against the correct package. The version parameter is optional but should be provided if possible, it should be the oldest version that we know to have the problem (example in #626232).

3.5 Forwarding bugs

Forwarding bugs means opening bug reports in the upstream bug tracker for issues that have been reported in Debian but that applies to the upstream (unmodified) source code. Be sure to include all the relevant information and a link to the corresponding Debian bug.

Depending on the upstream bug tracker, you might have to open an account to be able to file new bug reports.

On the Debian side, you must record that a bug has been forwarded with “bts forwarded XXXX upstream-bug-url”. upstream-bug-url is the URL corresponding to the upstream bug report you created (ex: http://projects.ciarang.com/p/feed2omb/issues/21/ recorded in #609345″).

If the upstream authors fix the bug you reported, you can tag the Debian bug with “fixed-upstream” so that it’s easier to find bugs to close when the next upstream release comes out (example in #637275).

3.6 Updating version information

The Debian BTS uses “version tracking” to know which package versions are affected by a given bug. It’s particularly important to have correct version information for release critical bugs since it might affect the migration of packages to testing.

You can learn more on this topic here: http://wiki.debian.org/HowtoUseBTS.

4. More advice

Colin Watson wrote a constructive rant explaining some mistakes that bug triagers are often doing. While it refers mainly to Ubuntu’s launchpad, the advice apply equally as well to Debian. Check it out to become a better bug triager!

Note that you can refer to this article with this shorter URL: https://raphaelhertzog.com/go/bugtriaging/

Do you want to read more tutorials like this one? Click here to subscribe to my free newsletter, you can opt to receive future articles by email.

Understand dpkg and don’t get stuck with a maintainer script failure

September 13, 2011 by Raphaël Hertzog

Continuing my series of articles on dpkg’s errors, this time I’ll cover a pretty common one which has several variations:

Setting up acpid (1:2.0.12-1) ...
rm: cannot remove `/etc/rc1.d/K20acpid': No such file or directory
dpkg: error processing acpid (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 acpid

Even if dpkg is failing and outputting the error message, the real problem is not in dpkg but in the installed package (acpid in the example above). As we already learned, a package contains not only files but also “maintainer scripts” that are executed at various points of the installation process (see some useful graphics to understand how they are called, thanks to Margarita Manterola).

In the introductory example it was acpid’s “post-installation script” that failed, and dpkg is only forwarding that failure back to the caller. The maintainer scripts are stored in /var/lib/dpkg/info/. You can thus inspect them and even modify them if you hit a bug and want to work around it (do this only if you understand what you do!).

One common modification is to add “set -x” at the start of the script and to retry the failing operation. That way you can see what’s executed exactly. Here’s what the output could look like after the addition of “set -x” to /var/lib/dpkg/info/acpid.postinst:

$ sudo dpkg --configure acpid
Setting up acpid (1:2.0.12-1) ...
+ dpkg --compare-versions 1:2.0.11-1 lt-nl 1.0.10-3
+ dpkg --compare-versions 1:2.0.11-1 lt-nl 1.0.6-16
+ dpkg --compare-versions 1:2.0.11-1 lt 1.0.6-6
+ rm /etc/rc1.d/K20acpid
rm: cannot remove `/etc/rc1.d/K20acpid': No such file or directory
dpkg: error processing acpid (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 acpid

This output helps you locate the command that is actually failing. Here’s it’s relatively easy since we have an error message from “rm”. And the fix is trivial too, we replace “rm” with “rm -f” so that it doesn’t fail when the file doesn’t exist (this is a fake bug I made up for this article—I just added a failing rm call—but it’s inspired by real bugs I experienced).

Maintainer scripts are supposed to be idempotent: we should be able to execute them several times in a row without bad consequences. It happens from time to time that the maintainer gets this wrong… on the first try it works, so he uploads his package and we discover the problem only later once someone ended up executing the same code twice for some reason.

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