Interview – Page 6

People behind Debian: Mike Hommey, Firefox/Iceweasel maintainer

February 3, 2011 by Raphaël Hertzog

For as long as I have known Mike, he’s been maintaining one of the largest (and most widely used) package: Iceweasel, Debian’s default web browser. It’s effectively Mozilla’s Firefox although it has been renamed to avoid some rules enforced by Mozilla’s trademark policy. But we might see Firefox back in Debian… read on to know Mike’s plans.

His story is also very interesting in that he went from simple user to Iceweasel maintainer, and now he’s working for Mozilla Corporation. But you already knew that contributing to free software is a good way to grow skills and gain experience that are valuable on the job market, right? 😉

My questions are in bold, the rest is by Mike.

Who are you?

I am Mike Hommey. I am French, even if my name doesn’t sound so.

I have been a GNU/Linux user since 1995, using Debian since 1999, and started packaging in 2003. After a long time in the NM queue, I became a DD in 2005.

The main reason I started being actively involved is quite selfish: I wanted some things done, and I just did them. My first packages were extensions for the Mozilla Suite, the old one that directly inherited from Netscape Communicator. Later on, I wanted some of these extensions to work with the new kid on the block: Phoenix; or maybe it was already Firebird. By then, integrating extensions was a hassle, and the mozilla-browser maintainer had come up with a script that would make it easier for extension packages. So I ported that script for use with Phoenix/Firebird and sent it to the BTS.

Then Phoenix/Firebird became Firefox, and it grew a real extension manager. Except that is was entirely not suited for extensions installed by the packaging system. So I made it work better. And made a few more changes to make Firefox work better. All through patches or NMUs.

Then I became co-maintainer, then Firefox couldn’t keep its name and became Iceweasel, and, fast-forward until today, I’m now taking care of Iceweasel/Xulrunner and Iceape in stable, unstable, experimental and an external repository.

This 8 years-long story (wow, I hadn’t even realized it had been that long until I wrote it) tells you something: newcomers shouldn’t be afraid to stick their hands anywhere, even in big packages. I was only a Mozilla and Phoenix end-user when I started.

Apart from Mozilla-related packaging, I also happen to (co-)maintain some other packages in Debian, most notably webkit, though I haven’t been very active in the pkg-webkit team recently. There are several reasons for that, the main one being that there are other team members getting the job done. And I can’t say that much about the pkg-mozilla team, since there are effectively no other team members.

What’s your biggest achievement within Debian?

I am quite proud that Squeeze will be the first Debian release where Iceweasel works on all supported architectures. Previously, we only knew the package compiled on all these architectures. Starting with Squeeze, we know it passes several of the test suites coming with the source code. This ensures most of the browser is functional. It was actually far from being the case before, as it appeared when the test suites were first enabled.

I think it is very important to have properly working packages on all our supported architectures. The current evolution of hardware shows how important it still is. Who would have thought a few years back that we would see ARM or MIPS based netbooks today ?

What are your plans for Debian Wheezy?

For Debian Wheezy, I would like to improve Iceweasel/Icedove/Iceape integration with the packaging system. Something that would allow to use the apt database to find extensions or plugins, on top of the current behaviour. I also want to improve desktop integration, most notably for KDE.

Another thing I’d like to see happen is to package google breakpad independently (its source code is currently embedded in chromium and iceweasel, though not built, as far as I know), and have our Mozilla products builds be able to send their crash reports upstream. It is very important that upstream gets direct visibility over what crashes on GNU/Linux systems. It helps making them aware of issues that would otherwise probably remain unnoticed, as there are much more users using distributions packages than upstream tarballs. And not all Debian users report crashes to the BTS. I know at least Fedora and SuSE are already doing it.

More importantly, I want to avoid the sad situation we got with Squeeze, where we’re going to release a 18 months old Iceweasel. We got there for a combination of reasons, one being that I was preparing for a freeze in December 2009 and focusing on getting 3.5 in shape instead of the then upcoming 3.6.

The result was that we didn’t get 3.6 packages before upstream released 3.6.3 in April 2010. By then it was too late, considering the uncertainty of the release schedule, to update reverse dependencies and get 3.6 ready for Squeeze.

Things are different for 4.0. I’m already getting ahead of things, and while reverse dependencies haven’t been taken care of, all beta releases have been made available through http://mozilla.debian.net/, usually within hours after upstream release (sometimes even a few hours before official announcement, but always after availability on ftp.mozilla.org). A great share of our patches were also pushed upstream.

Several things made that possible:

I’m now closely following upstream trunk
I’m starting to prepare packages when candidate builds are distributed upstream, which usually happens a few days ahead for betas, and more than a week ahead for stable releases.
I automated part of the package building process, and have a beefy build machine. I’m getting near being able to provide nightly builds of upstream trunk.

There will be a couple major upstream releases until Wheezy comes along, and I want to make them available early in unstable, even if that means breaking reverse dependencies until they are fixed.

Finally, I would like to get other people involved, starting with the Icedove maintainer. Volunteers are very much welcome, for any kind of involvement: bug triaging, documentation (which we are deeply lacking), testing, code… People interested can contact the pkg-mozilla team list. As the Debian packaging gets less time consuming, I should be able to spend more time mentoring, which should help.

If you could spend all your time on Debian, what would you work on?

I actually have been working almost full time on Debian for a few months during a more-or-less purposeful unemployment period. That’s when I attempted to add an alert popup when Iceweasel or extensions are upgraded (which was eventually removed because not working very effectively). That’s when I worked on Iceweasel 3.6 and the first 4.0 betas. That’s when I pushed more than 70 patches upstream, and got upstream commit access.

I know for a fact that keeping up with upstream and answering bug reports is already time consuming, and time comes in finite quantity. Working full time on Debian allows to do more than that, as I’ve been able to experience first hand. Unfortunately, that doesn’t help pay the bills, so it would be best if time could be shared with other persons. Like, actual members in the pkg-mozilla team. 😉

Anyways, if I were to work full time on Debian again, I’d like to do more than packaging, and help improve some of our infrastructure, most notably the buildd network, to grow some automated way to get packages built on all or some of our architectures. Call that PPA if you want, though I don’t think we need something exactly like PPA.

We sure do have porter boxes, but there is a huge overhead to get packages built there: you need to first try, then see you lack build dependencies, then wait for admins to install them, then come back and launch your build, and finally come back again much later to see how it went. And that’s when it goes smoothly. Repeat for each architecture.

It’s already cumbersome when it’s a small package, so imagine when it’s Iceweasel. I’d like to be able to push a (signed) .dsc somewhere, say I want it built on that and that architecture, and get binary packages and logs back. It could then be up to developers to distribute them, or not. Sometimes, you’re just interested in test suite results.

Another related wish would be a way to access build trees of failed builds, possibly on the buildd where it failed.

What’s the biggest problem of Debian?

Lack of contributors, lack of contributors, and… lack of contributors.

It can sound weird to say that in a community of 1000+ people. But the sad reality is that we’ve seen, repeatedly, calls for help in various places from various understaffed teams (most often of effectively one member) for years. So there is obviously a problem getting people to invest time in these teams either on the long term, or at all.

I know this is not a very significant metric, but it already should say a lot: I wouldn’t be surprised if more than 2/3 of the number of source lines of code in Debian come from less than 5% of the number of packages in the archive, and see less than 5% of the DD/DM population involved. If someone feels like doing the actual math, I’m curious to know how far I’m from reality, and in what direction.

We also lack manpower to be able to make our release development smoother. In a perfect world where manpower is not a scarce resource, we should work on $release+1 when $release is being frozen. Said otherwise, we should have been able to start working on Wheezy in August 2010, or even earlier.

You’ve been working for Mozilla Corporation for a few months. How does the work look like and what are you working on?

I am actually not working full time for MoCo; I am only contracting for 4 days a week. That was a request I made to keep having enough spare time for Debian or other activities. I am working from home, and am pretty much free about when I work, as long as I work long enough. I take advantage of this freedom and the saved commuting time to live a healthier life by doing some sports in the daytime (which also happens to be cheaper).

I mostly work with Taras Glek and other people on various aspects of Firefox startup performance. This involves pretty interesting low-level stuff, in which I actually got involved before being contracted. This work has nothing to do with packaging Iceweasel, though I can have a few opportunities to do things somehow related.

You told in your blog that you were discussing with Mozilla how Debian could use the Firefox trademark. Can you tell us a bit about the progress you made?

I have got an informal approval of the patches we are applying to the Iceweasel 4.0 beta packages. There are a few concerns about using the system cairo library, and the embedded copy of libpng needs to be used to have support for the animated PNGs that are used in the user interface and that are required in Firefox’ feature-set. Other than that, there are pretty much no objection on the technical side.

We managed to get to some common ground as to how to manage stable updates and more generally, changes to our packages, but I’m still waiting for an actual agreement draft. While I, as the maintainer, am fine with the way it should look according to my discussions with the people involved at Mozilla, I’ll seek review from my fellow Debian Developers when I’ll have something to show.

I haven’t decided yet how this will reflect on the Debian packages, though. For example, would Iceweasel stay? But I do hope Wheezy will get Firefox back.

Is there someone in Debian that you admire for their contributions?

Not someone, but all past, present and future release team members. This is a team that receives a lot of critics (and I indirectly gave one a few paragraphs ago), yet manages to keep doing an amazing job and its members are very committed to their task. I admire their dedication.

Thank you to Mike for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

People behind Debian: Michael Vogt, synaptic and APT developer

January 21, 2011 by Raphaël Hertzog

Michael and Marie — Michael and his daughter Marie

Michael has been around for more than 10 years and has always contributed to the APT software family. He’s the author of the first real graphical interface to APT—synaptic. Since then he created “software-center” as part of his work for Ubuntu. Being the most experienced APT developer, he’s naturally the coordinator of the APT team. Check out what he has to say about APT’s possible evolutions.

My questions are in bold, the rest is by Michael.

Who are you?

My name is Michael Vogt, I’m married and have two little daughters. We live in Germany (near to Trier) and I work for Canonical as a software developer. I joined Debian as a developer in early 2000 and started to contribute to Ubuntu in 2004.

What’s your biggest achievement within Debian or Ubuntu?

I can not decide on a single one so I will just be a bit verbose.

From the very beginning I was interested in improving the package manager experience and the UI on top for our users. I’m proud of the work I did with synaptic. It was one of the earliest UIs on top of apt. Because of my work on synaptic I got into apt development as well and fixed bugs there and added new features. I still do most of the uploads here, but nowadays David Kalnischkies is the most active developer.

I also wrote a bunch of tools like gdebi, update-notifier, update-manager, unattended-upgrade and software-properties to make the update/install situation for the user easier to deal with. Most of the tools are written in python so I added a lot of improvements to python-apt along the way, including the initial high level “apt” interface and a bunch of missing low-level apt_pkg features. Julian Andres Klode made a big push in this area recently and thanks to his effort the bindings are fully complete now and have good documentation.

My most recent project is software-center. Its aim is to provide a UI strongly targeted for end-users. The goal of this project is to make finding and installing software easy and beautiful. We have a fantastic collection of software to offer and software-center tries to present it well (including screenshots, instant search results and soon ratings&reviews). This builds on great foundations like aptdaemon by Sebastian Heinlein, screenshots.debian.net by Christoph Haas, ddtp.debian.org by Michael Bramer, apt-xapian-index by Enrico Zini and many others (this is what I love about free software, it usually “adds”, rarely “takes away”).

What are your plans for Debian Wheezy?

For apt I would love to see a more plugable architecture for the acquire system. It would be nice to be able to make apt-get update (and the frontends that use this from libapt) be able to download additional data (like debtags or additional index file that contains more end-user targeted information). I also want to add some scripts so that apt (optionally) creates btrfs snapshots on upgrade and provide some easy way to rollback in case of problems.

There is also some interesting work going on around making the apt problem resolver a more plugable part. This way we should be able to do much faster development.

software-center will get ratings&reviews in the upstream branch, I really hope we can get that into Wheezy.

If you could spend all your time on Debian, what would you work on?

In that case I would start with a refactor of apt to make it more robust about ABI breaks. It would be possible to move much faster once this problem is solved (its not even hard, it just need to be done). Then I would add a more complete testsuite.

Another important problem to tackle is to make maintainer scripts more declarative. I triaged a lot of upgrade bug reports (mostly in ubuntu though) and a lot of them are caused by maintainer script failures. Worse is that depending on the error its really hard for the user to solve the problem. There is also a lot of code duplication. Having a central place that contains well tested code to do these jobs would be more robust. Triggers help us a lot here already, but I think there is still more room for improvement.

What’s the biggest problem of Debian?

That’s a hard question 🙂 I mostly like Debian the way it is. What frustrated me in the past were flamewars that could have been avoided. To me being respectful to each other is important, I don’t like flames and insults because I like solving problems and fighting like this rarely helps that. The other attitude I don’t like is to blame people and complain instead of trying to help and be positive (the difference between “it sucks because it does not support $foo” instead of “it would be so helpful if we had $foo because it enables me to let me do $bar”).

For a long time, I had the feeling you were mostly alone working on APT and were just ensuring that it keeps working. Did you also had this feeling and are things better nowadays ?

I felt a bit alone sometimes 🙂 That being said, there were great people like Eugene V. Lyubimkin and Otavio Salvador during my time who did do a lot of good work (especially at release crunch times) and helped me with the maintenance (but got interested in other area than apt later). And now we have the unstoppable David Kalnischkies and Julian Andres Klode.

Apt is too big for a single person, so I’m very happy that especially David is doing superb work on the day-to-day tasks and fixes (plus big project like multiarch and the important but not very thankful testsuite work). We talk about apt stuff almost daily, doing code reviews and discuss bugs. This makes the development process much more fun and healthy. Julian Andres Klode is doing interesting work around making the resolver more plugable and Christian Perrier is as tireless as always when it comes to the translations merging.

I did a quick grep over the bzr log output (including all branch merges) and count around ~4300 total commits (including all revisions of branches merged). Of that there ~950 commits from me plus an additional ~500 merges. It was more than just ensuring that it keeps working but I can see where this feeling comes from as I was never very verbose. Apt also was never my “only” project, I am involved in other upstream work like synaptic or update-manager or python-apt etc). This naturally reduced the time available to hack on apt and spend time doing the important day-to-day bug triage, response to mailing list messages etc.

One the python-apt side Julian Andres Klode did great work to improve the code and the documentation. It’s a really nice interface and if you need to do anything related to packages and love python I encourage you to try it. Its as simple as:

import apt
cache = apt.Cache()
cache["update-manager"].mark_install()
cache.commit()

Of course you can do much more with it (update-manager, software-center and lots of more tools use it). With “pydoc apt” you can get a good overview.

The apt team always welcomes contributors. We have a mailing list and a irc channel and it’s a great opportunity to solve real world problems. It does not matter if you want to help triage bugs or write documentation or write code, we welcome all contributors.

You’re also an Ubuntu developer employed by Canonical. Are you satisfied with the level of cooperation between both projects? What can we do to get Ubuntu to package new applications developed by Canonical directly in Debian?

Again a tricky question 🙂 When it comes to cooperation there is always room for improvement. I think (with my Canonical hat on) we do a lot better than we did in the past. And it’s great to see the current DPL coming to Ubuntu events and talking about ways to improve the collaboration. One area that I feel that Debian would benefit is to be more positive about NMUs and shared source repositories (collab-maint and LowThresholdNmu are good steps here). The lower the cost is to push a patch/fix (e.g. via direct commit or upload) the more there will be.

When it comes to getting packages into Debian I think the best solution is to have a person in Debian as a point of contact to help with that. Usually the amount of work is pretty small as the software will have a debian/* dir already with useful stuff in it. But it helps me a lot to have someone doing the Debian uploads, responding to the bugmail etc (even if the bugmail is just forwarded as upstream bugreports 🙂 IMO it is a great opportunity especially for new packagers as they will not have to do a lot of packaging work to get those apps into Debian. This model works very well for me for e.g. gdebi (where Luca Falavigna is really helpful on the Debian side).

Is there someone in Debian that you admire for his contributions?

There are many people I admire. Probably too many to mention them all. I always find it hard to single out individual people because the project as a whole can be so proud of their achievements.

The first name that comes to my mind is Jason Gunthorpe (the original apt author) who I’ve never met. The next is Daniel Burrows who I met and was inspired by. David Kalnischkies is doing great work on apt. From contributing his first (small) patch to being able to virtually fix any problem and adding big features like multiarch support in about a year. Sebastian Heinlein for aptdaemon.

Christian Perrier has always be one of my heroes because he cares so much about i18n. Christoph Haas for screenshots.debian.net, Michael Bramer for his work on debian translated package descriptions.

Thank you to Michael for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

People behind Debian: Mehdi Dogguy, release assistant

December 23, 2010 by Raphaël Hertzog

Mehdi is a Debian developer for a bit more than a year, and he’s already part of the Debian Release Team. His story is quite typical in that he started there by trying to help while observing the team do its work. That’s a recurrent pattern for people who get co-opted in free software teams.

Read on for more info about the release team, and Mehdi’s opinion on many topics. My questions are in bold, the rest is by Mehdi (except for the additional information that I inserted in italics).

Who are you?

I’m 27 years old. I grew up in Ariana in northern Tunisia, but have been living in Paris, France, since 2002.

I’m a PhD Student at the PPS laboratory where I study synchronous concurrent process calculi.

I became interested in Debian when I saw one of my colleagues, Samuel Mimram (first sponsor and advocate) trying to resolve #440469, which is a bug reported against a program I wrote. We have never been able to resolve it but my intent to contribute was born there. Since then, I started to maintain some packages and help where I can.

What’s your biggest achievement within Debian?

I don’t think I had time to accomplish a lot yet 🙂 I’ve been mostly active in the OCaml team where we designed a tool to compute automatically the dependencies between OCaml packages, called dh-ocaml. This was a joint work with Stéphane Glondu, Sylvain Le Gall and Stefano Zacchiroli. I really appreciated the time spent with them while developing dh-ocaml. Some of the bits included in dh-ocaml have been included upstream in their latest release.

I’ve also tried to give a second life to the Buildd Status Pages because they were (kind of) abandoned. I intend to keep them alive and add new features to them.

If you had a wand and could change one thing in Debian, what would that be?

Make OCaml part of a default Debian installation 😀

But, since I’m not a magician yet, I’d stick to more realistic plans:

A lot of desktop users fear Debian. I think that the Desktop installation offered by Debian today is very user-friendly and we should be able to attract more and more desktop users. Still, there is some work to be done in various places to make it even more attractive. The idea is trying to enhance the usability and integration of various tools together. Each fix could be easy or trivial but the final result would be an improved Desktop experience for our users. Our packaged software run well. So, each person can participate since the most difficult part is to find the broken scenarios. Fixes could be found together with maintainers, upstream or other interested people.
I’ll try to come up with a plan, a list of things that need polishing or fixes and gather a group of people to work on it. I’d definitely be interested in participating in such a project and I hope that I’ll find other people to help. If the plan is clear enough and has well described objectives and criteria, it could be proposed to the Release Team to consider it as a Release Goal for Wheezy.
NMUs are a great way to make things move forward. But, sometimes, an NMU could break things or have some undesirable effects. For now, NMUers have to manually track the package’s status for some time to be sure that everything is alright. It could be a good idea to be auto-subscribed to the bugs notifications of NMUed packages for some period of time (let’s say for a month) to be aware of any new issues and try to fix them. NMUing a package is not just applying a patch and hitting enter after dput. It’s also about making sure that the changes are correct and that no regressions have been introduced, etc…
Orphaned packages: It could be considered as too strict and not desired, but what about not keeping orphaned and buggy packages in Testing? What about removing them from the archive if they are buggy and still unmaintained for some period? Our ftp archive is growing. It could make sense to do some (more strict) housekeeping. I believe that this question can be raised during the next QA meeting. We should think about what we want to do with those packages before they rot in the archive.

[Raphael Hertzog: I would like to point out that pts-subscribe provided by devscripts makes it easy to temporarily subscribe to bug notifications after an Non-Maintainer Upload (NMU).]

You’re a Debian developer since August 2009 and you’re already an assistant within the Release Management team. How did that happen and what is this about?

In the OCaml team, we have to start a transition each time we upload a new version of the OCaml compiler (actually, for each package). So, some coordination with the Release Team is needed to make the transition happen.

When we are ready to upload a new version of the compiler, we ask the Release Team for permission and wait for their ack. Sometimes, their reply is fast (e.g. if their is no conflicting transition running), but it’s not always the case. While waiting for an ack, I used to check what was happening on debian-release@l.d.o. It made me more and more interested in the activities of the Release Team.

Then (before getting my Debian account), I had the chance to participate in DebConf9 where I met Luk and Phil. It was a good occasion to see more about the tools used by the Release Team. During April 2010, I had some spare time and was able to implement a little tool called Jamie to inspect the relations between transitions. It helps us to quickly see which transitions can run in parallel, or what should wait. And one day (in May 2010, IIRC), I got offered by Adam to join the team.

As members of the Release Team, we have multiple areas to work on:

Taking care of transitions during the development cycle, which means making sure that some set of packages are correctly (re-)built or fixed against a specific (to each transition) set of packages, and finding a way to tell Britney that those packages can migrate and it would be great if she also shared the same opinion. [Raphael Hertzog: britney is the name of the software that controls the content of the Testing distribution.]
Paying attention to what is happening in the archive (uploads, reported RC bugs, etc…). The idea is to try to detect unexpected transitions, blocked packages, make sure that RC bug fixes reach Testing in a reasonable period of time, etc…
During a freeze, making sure that unblock requests and freeze exceptions are not forgotten and try to make the RC bug count decrease.

There are other tasks that I’ll let you discover by joining the game.

Deciding what goes (or not) in the next stable release is a big responsibility and can be incredibly difficult at times. You have to make judgement calls all the time. What are your own criteria?

That’s a very hard to answer question (at least, for me). It really depends on the “case”. I try to follow the criteria that we publish in each release update. Sometimes, an unblock request doesn’t match those criteria and we have to decide what to accept from the set of proposed changes. Generally, new features and non-fixes (read new upstream versions) changes are not the kind of changes that we would accept during the freeze. Some of them could be accepted if they are not intrusive, easy and well defended. When, I’m not sure I try to ask other members of the Release Team to see if they share my opinion or if I missed something important during the review. The key point is to have a clear idea on what’s the benefit of the proposed update, and compare it to the current situation. For example, accepting a new upstream release (even if it fixes some critical bugs) is taking a risk to break other features and that’s why we (usually) ask for a backported fix.

It’s also worth noticing that (most of the time) we don’t decide what goes in, but (more specifically) what version of a given package goes in and try to give to the contributors an idea on what kind of changes are acceptable during the freeze. There are some exceptions though. Most of them are to fix a critical package or feature.

Do you have plans to improve the release process for Debian Wheezy?

We do have plans to improve every bit in Debian. Wheezy will be the best release ever. We just don’t know the details yet 🙂

During our last meeting in Paris last October, the Release Team agreed to organize a meeting after Squeeze’s release to discuss (among other questions) Wheezy’s cycle. But the details of the meeting are not fixed yet (we still have plenty of time to organize it… and other more important tasks to care about). We would like to be able to announce a clear roadmap for Wheezy and enhance our communication with the rest of the project. We certainly want to avoid what happened for Squeeze. Making things a bit more predictable for developers is one of our goals.

Do you think the Constantly Usable Testing project will help?

The original idea by Joey Hess is great because it allows d-i developers to work with a “stable” version of the archive. It allows them to focus on the new features they want to implement or the parts they want to fix (AIUI). It also allows to have constantly available and working installation images.

Then, there is the idea of having a constantly usable Testing for users. The idea seems nice. People tend to like the idea behind CUT because they miss some software disappearing from Testing and because of the long delays for security fixes to reach Testing.

If the Release Team has decided to remove a package from Testing, I think that there must be a reason for that. It either means that the software is broken, has unfixed security holes or was asked for the removal by its maintainer. I think that we should better try to spend some time to fix those packages, instead of throwing a broken version in a new suite. It could be argued that one could add experimental’s version in CUT (or sid’s) but every user is free to cherry-pick packages from the relevant suite when needed while still following Testing as a default branch.

Besides, it’s quite easy to see what was removed recently by checking the archive of debian-testing-changes or by querying UDD. IMO, It would be more useful to provide a better interface of that archive for our users. We could even imagine a program that alerts the user about installed software that got recently removed from Testing, to keep the user constantly aware any issue that could affect his machine. About the security or important updates, one has to recall the existence of Testing-security and testing-proposed-updates that are used specifically to let fixes reach Testing as soon as possible when it’s not possible to go through Unstable. I’m sure that the security team would appreciate some help to deal with security updates for Testing. We also have ways to speed migrate packages from Unstable to Testing.

I have to admit that I’m not convinced yet by the benefits brought by CUT for our users.

Thank you to Mehdi for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

People behind Debian: David Kalnischkies, an APT developer

December 10, 2010 by Raphaël Hertzog

The two first interviews were dedicated to long-time Debian developers. This time I took the opposite approach, I interviewed David Kalnischkies who is not (yet) a Debian developer. But he’s contributing to one of the most important software within Debian—the APT package manager—since 2009. You can already see him in many places in Debian sharing his APT knowledge when needed.

English is not his native language and he’s a bit shy, but he accepted the interview nevertheless. I would like to thank him for the efforts involved and I hope his story can inspire some people to take the leap and just start helping… My questions are in bold, the rest is by David.

Who are you?

I am David Kalnischkies, 22 years old, living in the small town Erbach near Wiesbaden in Germany and I’m studying computer science at the TU Darmstadt. Furthermore I am—for more than half a decade now—young group leader of my hometown.

I never intended to get into this position, but it has similarities with my “career” in this internet-thingy here. I don’t remember why, but in April 2009 I was at a stage that some simple bugs in APT annoyed me so much that I grabbed the source, and most importantly—I don’t know why I did it— but I published my changes in Mai with #433007, a few more bugs and even a branch on launchpad. And this public branch got me into all this trouble in June: I got a mail from “Mr. package managment” Michael Vogt regarding this branch…

A few days later I joined an IRC session with him and closely after that my name appeared for the first time in a changelog entry. It’s a strange but also addicting feeling to read your own name in an unfamiliar place. And even now after many IRC discussions, bugfixes and features, three Ubuntu Developer Summits and a Google Summer of Code in Debian, my name still appear in places I have never even thought about—e.g. in an interview.

What’s your biggest achievement within Debian?

I would like to answer “MultiArch in APT” as it was my Google Summer of Code project, but as it has (not much) use for the normal user at this point—will hopefully change for wheezy—I chose three smaller things in squeeze’s APT that many people don’t even know yet:

“MMap run out of room”, the most famous error related to the APT::Cache-Limit option is gone. The DynamicMMap in APT now deserves its name 🙂
Download and usage of multiple Translations of Descriptions
crazy stuff like apt-cache show ^apt-.*$/experimental works

If your impression is now that I only do APT stuff: that’s completely right, but that’s already more than enough for me for now as the toolchain behind the short name APT contains so many tools and use cases that you always have something different.

You’re an active member of the APT development team. Are there plans for APT in Debian Wheezy? What features can we expect?

That’s very hard to answer, as the team is too small to be able to really plan something. I mean, you can have fancy plans and everything and half a second later someone arrives on the mailing list with a “small” question which eats days of development time just for debugging…

But right now the TODO list contains (in no particular order):

MultiArch – managing packages built for different architectures like i386 on amd64 to ease the usage of packages which only work on specific architectures or cross-compiling.
rewriting the subsystem responsible for downloading files to e.g. enable tools like apt-file or debtags to reuse the infrastructure by plugging into it.
splitting long descriptions out of the Packages file to possibly decrease the size to download on an “apt-get update”. Includes mostly pulling the button only to enable it by the archive masters
backporting popular features of some frontends to enable all frontends to use them, e.g. “apt-get changelog” or “apt-get download”
support research on resolver improvements by implementing support for a distribution independent upgrade problem format (CUDF).
an additional single binary for users wrapping apt-get, apt-cache and co.
getting in contact (again) with various forks like apt-rpm and derivatives like maemo or telesphoreo to join forces instead of splitting them by working on different (and possibily very old) heads of the dragon

We will see what will get real for wheezy and what is postponed, but one thing is sure: more will be done for wheezy if you help!

If you could spend all your time on Debian, what would you work on?

I would spend it on APT’s debbugs count… zero would be cool to look at! We make progress in this regard, but with the current velocity we will reach it in ten years or so.

Reading more mailing lists would be interesting, as I am kind of an information junky. Maintaining a package could be interesting to share the annoyance of a maintainer with handcrafted dependencies just to notice that APT doesn’t get it in the way I intended it to be. Through, to make it feel real I need to train a few new APT contributors before so they can point my mistake out, but this unfortunately doesn’t depend so much on time but on victims… Maybe I could even be working on getting an official status.

Beside that, I would love to be able to “apt-get dist-upgrade” the increasing mass of systems I and many others carry around in their pockets. In regards to my phone, this is already fixed, but there is much room for improvements.

What’s the biggest problem of Debian?

You need to be lucky. You need to talk at the right time to the right person. That’s not really a debian-only problem as such, but in a global project full of volunteers you can see it clearly as there are plenty of opportunities to be unlucky.

For example, it’s unlikely that an interview would be made with me now if Michael had not contacted me in June 2009. In a big project like Debian, you are basically completely lost without a mentor guiding you, so things like the debian-mentors list are good projects, but I am pretty certain they could benefit from some more helping hands.

The other thing which I consider a problem is that—and I read from time to time—some people don’t care for translations. That’s bad. Yes, a developer is able to read English, otherwise s/he couldn’t write code or participate on the mailinglists.

Still, I personally prefer to use a translated application if I have the chance as it’s simply easier for me to read in my mother tongue, not only because I am dyslexic, but because my mind still thinks in German and not in English. Yes, I could personally fix that by thinking in English only from now on, but its a quite big problem to convince my family—which is not really familiar with tech-stuff—to use something if they can’t understand what is written on screen.

It was hard enough to tell my mother how to write an SMS in a German interface. My phone with English words all over the place would be completely unusable for her—despite the fact that my phone is powered by Debian and better for the task from a technical point of view.

You are not yet an official Debian developer/maintainer, but you’re already perceived in the community as one the most knowledgeable person about APT. It’s a great start! What’s your advice to other people who want to start contributing to Debian in general, and to APT in particular?

It was never a goal in my life to “start contributing”. My goal was and still is to make my life easier by letting the computer work for me. At some point APT hindered the success of this goal, so it needed to be fixed. I didn’t expect to open pandora’s box.

So, my advice is simple: Just start. Ignore the warning signs telling you that this is not easy. They are just telling you that you do something useful. Only artificial problems are easy. Further more, contribution to APT, dpkg or any other existing package is in no way harder than opening an ITP and working on your own, and it’s cooler as you have a similar minded team around you to talk to. 🙂

“APT didn’t accept release codenames as target release” was one of the first things I fixed. If I had asked someone if that would be a good starting point the answer would have been a clear “no”, but I didn’t search for a good starting point…

As a kid I can start playing football by just walking on the field and play or I can sit near the field, watching the others play, while analyzing which position would be the best for me to start ruling out one by one as the technical requirements seem too high… “Oh – bicycle kick – that sounds complicated… I can’t do that”

Julian Andreas Klode is working on a APT replacement, there’s also Cupt by Eugene V. Lyubimkin. Both projects started because their authors are not satisfied with APT, they find APT’s code difficult to hack partly due to the usage of C++. Do you share their concerns and what’s your opinion on those projects?

I don’t think C++ is a concern in this regard, after all cupt is currently rewritten to C++0x and APT2 started in vala and is now C + glib—last time I checked at least. I personally think that something is wrong if we need to advertise an application by saying in which language it is written…

The major “problem” for APT is probably that the code is “old”: APT does its job for more than 12 years now, under different maintainers with an always changing environment around it: so there are lines in APT which date from a time when nobody knew what a “Breaks” dependency is, that packages can have long descriptions which can be translated or even that package archives can be signed with a gpg key! And yet we take all those for granted today. APT has proven to adapt to these changes in the environment and became in this process very popular. So I don’t think the point is near (if it will come at all) that APT can go into retirement as it is completely replaced by something else.

The competitors one the other hand have their first 12 years still to go. And it will be interesting to see how they will evolve and what will be the state of the art in 2022…

But you asked what I think about the competitors: I prefer the “revolution from inside” simply because I can see effects faster as more users will profit from it now. Cupt and co. obviously prefer the “normal” revolution. The goal is the same, creating the best package manager tool, but the chosen way to the goal is different. aptitude and cupt have an interactive resolver for example: that’s something I dislike personally, for others that is the ultimate killer feature. cupt reading the same preference file as APT will have a different pinning result, which we should consider each time someone mentions the word “drop-in replacement”.

APT2 isn’t much more than the name—which I completely dislike—currently from a user point of view, so I can’t really comment on that. All of them make me sad as each line invested in boilerplate code like configuration file parsing would be in my eyes better be spent in a bugfix or new feature instead, but I am not here to tell anyone what they should do in their free time…

But frankly, I don’t see them really as competitors: I use the tools I use, if other do that too that’s good, if not that’s their problem. 🙂 The thing that annoys me really are claims like “plan is to remove APT by 2014” as this generates a “vi vs. emacs” like atmosphere we don’t need. If some people really think emacs is a good editor… who cares?

I really hope we all can drink a beer in 2022 in Milliways, the restaurant at the end of the package universe, remembering the good old 2010… 😉

Is there someone in Debian that you admire for his contributions?

No, not one, many!

Michael Vogt who has nearly the monopole of “package manager maintainer” by being upstream of APT, synaptics and software center to name only the biggest and still has the time to answer even the dumbest of my questions. 🙂 Jason Gunthorpe for being one of the initial developers behind “deity” who I will probably never meet in person beside in old comments and commit logs. Christian Perrier for caring so much about translations. Obey Arthur Liu as a great admin for Debian’s participation in Google’s Summer of Code. Paul Wise for doing countless reviews on debian-mentors which are a good source of information—not only for the maintainer of the package under review.

I guess I need to stop here because you asked for just one. So let’s end with some big words instead: I am just a little cog in the big debian wheel…

Thank you to David Kalnischkies for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.

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