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Preview: nomeata’s mind shares - Debian

nomeata’s mind shares



Joachim Breitners Denkblogade



 



Reproducible Builds World Summit

Fri, 04 Dec 2015 22:46:52 +0100

This week, I was attending the first Reproducible Builds World Summit in Athens. A while ago, I have fixed some reproducibility bugs in the Haskell compiler GHC (parts of #4012), and that got me a ticket to this fully sponsored and nicely organised event.

This was the first event I attended that had a dedicated and professional moderator, Gunner from Aspiration, who came up with a suitable on-the-fly-schedule, ensured the time was structured by shorter plenary rounds with all ~40 attendees as well as longer working sessions in groups of usually at most 10 people, motivated people to run (“facilitate”) these working groups as well as ensured that any results were noted and collected. This definitely makes a difference to the otherwise unstructured “let’s all sit in a big circle and endlessly discuss things“ or “let’s all just hack on what we want to hack on right now” structure of less professionally organised meetings.

But after 1½ days of talking, a certain desire to hack and get work done could be felt throughout the group, so most of us were happy to be allowed to make use of the laptop on Wednesday afternoon. At least as far as possible – the wireless was not expecting this crowd, it seems.

Besides the few patches above, my involvement in the project is rather rudimentary, so I tried to contribute as far as possible during the event itself. This was not always easy, as many of the working sessions were either self-reflecting or forward-facing: What problems do we see? What should we get done next? How do we talk to users/upstream/press/doners? Where possible, I tried to at least be helpful in the discussion.

During the hacking sessions, I found it most useful to contribute to diffoscope, a program to recursively and deeply show the difference between files of any format, so there are now patches to implement a multi-file HTML output, to more efficiently include large diffs, and – more importantly – I assisted Lunar in making diffoscope multi-threaded. In Python this is not a very great experience; I guess I am spoiled by Haskell (as it is often the case).

I enjoyed the group; a bit like DebConf but with many new faced from similarly-minded, but different projects. It was, however, again a Free Software event with an embarrassing low number of female participants. I liked discussing a proof of Gödel’s first incompleteness theorem during a skill exchange session. Unfortunately, I had to leave very timely after the event on Thursday evening, in order to attend the Haskell in Leipzig workshop.




Quickest path to a local apt repository

Sat, 22 Aug 2015 15:48:41 +0200

As I’m writing this, DebConf 15 is coming to an end. I spend most of my time improving the situation of the Haskell Packages in Debian, by improving the tooling and upgrading our packages to match Stackage 3.0 and build against GHC 7.10. But that is mostly of special interest (see this mail for a partial summary), so I’d like to use this post to advertise a very small and simple package I just uploaded to Debian:

During one of the discussion here I noticed that it is rather tricky to make a locally built package available to apt-get. The latest version in unstable allows one to install a debian package simply by running apt-get install on it, but in some cases, e.g. when you want a convenient way to list all packages that you made available for local use, this is insufficient.

So the usual approach is to create a local apt repository with your packages. Which is non-trivial: You can use dpkg-scanpackage, apt-ftparchive or reprepro. You need to create the directories, run the commands, add the repository to your local sources. You need to worry about signing it or setting the right options to make apt-get accept it without signing.

It is precisely this work that my new package local-apt-repository automates for you: Once it is installed, you simply drop the .deb file into /srv/local-apt-repository/ and after the next apt-get update the package can be installed like any other package from the archive.

I chose to use the advanced features that systemd provides – namely activation upon path changes – so works best with systemd as the init system.

If you want to contribute, or test it before it passes the NEW queue, check out the git repository.




Can one recommend Debian stable to Desktop users?

Sat, 01 Nov 2014 14:52:28 +0100

My significant other is running Debian stable on her laptop, and it has worked fine for quite a while. But since a week or two, she could not access her University IMAP account via Evolution. Obviously quite a showstopper!

Today I had a closer look, and my suspicion was that the University changed their SSL configuration due to the recent POODLE attack and that Evolution was incompatible with that. After some more searching, I found that Ubuntu had applied a patch, originally from Fedora, two weeks ago. For Debian, there is a bug report but no sign of action.

So I fetched the sources, applied the patch, built the package, installed it and things were working again. Yay for that! But this is obviously not the best way to handle such issues.

I know that Debian is volunteer driven and we often lack the manpower for certain things, so I don’t want to rant about this particular issue. I also continue to be a happy user of Debian unstable on my laptop, and Debian stable on my servers. But I seriously wonder: Can I really recommend Debian stable to users, for their laptops and desktops? If not, what are the alternatives? Ubuntu obviously comes to mind, having some full-time staff for such issues... But that would be giving up on promoting Debian as the universal operating system.

Update (2010-11-3): Laney just uploaded a fixed package. Thanks!




Switching to systemd-networkd

Tue, 14 Oct 2014 20:26:13 +0200

Ever since I read about systemd-networkd being in the making I was looking forward to try it out. I kept watching for the package to appear in Debian, or at least ITP bugs. A few days ago, by accident, I noticed that I already have systemd-networkd on my machine: It is simply shipped with the systemd package! My previous setup was a combination of ifplugd to detect when I plug or unplug the ethernet cable with a plain DHCP entry in /etc/network/interface. A while ago I was using guessnet to do a static setup depending on where I am, but I don’t need this flexibility any more, so the very simple approach with systemd-networkd is just fine with me. So after stopping ifplugd and $ cat > /etc/systemd/network/eth.network <<__END__ [Match] Name=eth0 [Network] DHCP=yes __END__ $ systemctl enable systemd-networkd $ systemctl start systemd-networkd I was ready to go. Indeed, systemd-networkd, probably due to the integrated dhcp client, felt quite a bit faster than the old setup. And what’s more important (and my main motivation for the switch): It did the right thing when I put it to sleep in my office, unplug it there, go home, plug it in and wake it up. ifplugd failed to detect this change and I often had to manually run ifdown eth0 && ifup eth0; this now works. But then I was bitten by what I guess some people call the viral nature of systemd: systemd-networkd would not update /etc/resolv.conf, but rather relies on systemd-resolved. And that requires me to change /etc/resolv.conf to be a symlink to /run/systemd/resolve/resolv.conf. But of course I also use my wireless adapter, which, at that point, was still managed using ifupdown, which would use dhclient which updates /etc/resolv.conf directly. So I investigated if I can use systemd-networkd also for my wireless account. I am not using NetworkManager or the like, but rather keep wpa_supplicant running in roaming mode, controlled from ifupdown (not sure how that exactly works and what controls what, but it worked). I found out that this setup works just fine with systemd-networkd: I start wpa_supplicant with this service file (which I found in the wpa_supplicant repo, but not yet in the Debian package)(which comes with the Debian package since version 2.5-1): [Unit] Description=WPA supplicant daemon (interface-specific version) Requires=sys-subsystem-net-devices-%i.device After=sys-subsystem-net-devices-%i.device [Service] Type=simple ExecStart=/sbin/wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant-%I.conf -i%I [Install] Alias=multi-user.target.wants/wpa_supplicant@%i.service After enabling this with systemctl enable wpa_supplicant@wlan0.service, systemd starts wpa_supplicant and wpa_supplicant will get the interface up and down as it goes, while systemd-networkd, equipped with [Match] Name=wlan0 [Network] DHCP=yes does the rest. So suddenly I have a system without /etc/init.d/networking and without ifup. Feels a bit strange, but also makes sense. I still need to migrate how I manage my UMTS modem device to that model. The only thing that I’m missing so far is a way to trigger actions when the network configuration has changes, like I could with /etc/network/if-up.d/ etc. I want to run things like killall -ALRM tincd and exim -qf. If you know how to do that, please tell me, or answer over at Stack Exchange.[...]



DebConf 14

Sat, 30 Aug 2014 15:10:58 -0700

I’m writing this blog post on the plane from Portland towards Europe (which I now can!), using the remaining battery live after having watched one of the DebConf talks that I missed. (It was the systemd talk, which was good and interesting, but maybe I should have watched one of the power management talks, as my battery is running down faster than it should be, I believe.) I mostly enjoyed this year’s DebConf. I must admit that I did not come very prepared: I had neither something urgent to hack on, nor important things to discuss with the other attendees, so in a way I had a slow start. I also felt a bit out of touch with the project, both personally and technically: In previous DebConfs, I had more interest in many different corners of the project, and also came with more naive enthusiasm. After more than 10 years in the project, I see a few things more realistic and also more relaxed, and don’t react on “Wouldn’t it be cool to have crazy idea” very easily any more. And then I mostly focus on Haskell packaging (and related tooling, which sometimes is also relevant and useful to others) these days, which is not very interesting to most others. But in the end I did get to do some useful hacking, heard a few interesting talks and even got a bit excited: I created a new tool to schedule binNMUs for Haskell packages which is quite generic (configured by just a regular expression), so that it can and will be used by the OCaml team as well, and who knows who else will start using hash-based virtual ABI packages in the future... It runs via a cron job on people.debian.org to produce output for Haskell and for OCaml, based on data pulled via HTTP. If you are a Debian developer and want up-to-date results, log into wuiet.debian.org and run ~nomeata/binNMUs --sql; it then uses the projectb and wanna-build databases directly. Thanks to the ftp team for opening up incoming.debian.org, by the way! Unsurprisingly, I also held a talk on Haskell and Debian (slides available). I talked a bit too long and we had too little time for discussion, but in any case not all discussion would have fitted in 45 minutes. The question of which packages from Hackage should be added to Debian and which not is still undecided (which means we carry on packaging what we happen to want in Debian for whatever reason). I guess the better our tooling gets (see the next section), the more easily we can support more and more packages. I am quite excited by and supportive of Enrico’s agenda to remove boilerplate data from the debian/ directories and relying on autodebianization tools. We have such a tool for Haskell package, cabal-debian, but it is unofficial, i.e. neither created by us nor fully endorsed. I want to change that, so I got in touch with the upstream maintainer and we want to get it into shape for producing perfect Debian packages, if the upstream provided meta data is perfect. I’d like to see the Debian Haskell Group to follows Enrico’s plan to its extreme conclusion, and this way drive innovation in Debian in general. We’ll see how that goes. Besides all the technical program I enjoyed the obligatory games of Mao and Werewolves. I also got to dance! On Saturday night, I found a small but welcoming Swing-In-The-Park event where I could dance a few steps of Lindy Hop. And on Tuesday night, Vagrant Cascadian took us (well, three of us) to a blues dancing night, which I greatly enjoyed: The style was so improvisation-friendly that despite having missed the introduction and never having danced Blues before I could jump right in. And in contrast to social dances in Germany, where it is often announced that the girls are also invited to ask the boys, but then it is still mostly the boys who have to ask, here I took only half a minute of standing at the side until I got asked to dance. In retrospect I should have skipped the HP reception and went there directly... I’m not heading ho[...]



Breaking News: Debian TC leaked decision on init system

Sun, 17 Nov 2013 09:33:17 Z

According to the German news page “heisse news”, the Debian Technical Committee has made a decision on the question about the default init system in Debian: There will be none!

Instead, according to Ian “Vorlon” Bart, Debian will start to distribute a suspend-to-disk image to their users, with all daemons already started, completely eradicating the need for an init system. If you are able to read German, read all about it at Debian Technical Committee entscheidet sich gegen ein Init-System




The carbondioxide footprint of Debian's Haskell packages

Wed, 24 Apr 2013 11:36:02 Z

By now, Debian ships quite a lot of Haskell packages (~600). Because of GHC's ABI volatility, whenever we upload a new version of a library, we have to rebuild all libraries that depend on that. In particular, if we upload a new version of the compiler itself, we have to rebuild all Haskell library packages. So we have to rebuild stuff a lot. Luckily, Debian has a decent autobuilding setup so that I just need to tell it what to rebuild, and the rest happens automatically (including figuring out the actual order to build things).

I was curious how much we use the buildd system compared to other packages, and also how long the builders are busy building Haskell packages. All the data is in a postgresql database on buildd.debian.org, so with some python and javascript code, I can visualize this. The graphs show the number of all uploads by autobuilder on the amd64 architecture, with haskell uploads specially marked, and the second graph does the same for the build time. You can select time ranges and get aggregate statistics for that time span.

During the last four days a complete rebuild was happening, due to the upload of GHC 7.6.3. During these 2 days and 18 hours building 537 packages took 48 hours of build time and produced 15kg of CO2. That is 94% of all uploads and 91% the total build time. The numbers are lower for the whole of last year: 52% of uploads, 31% of build time and 57kg of CO2. (The CO2 numbers are very rough estimates.)

Note that amd64 is a bit special, as most packages are uploaded on this architecture by the developers, so no automatic builds are happening. On other architectures have, every upload of a (arch:any) package is built, so the share of Haskell packages will be lower. Unfortunately, at the moment the database does not provide me with a table across all architectures (and I was too lazy to make it configurable yet).




Going to FOSDEM after all

Thu, 31 Jan 2013 20:03:50 Z

Earlier this week, things were looking different, and I did have to cancel a Haskell talk in Freiburg on Monday due to illness. But I’m back on track and will be travelling to Brussels tomorrow.

I’ll be holding a talk on how we package Haskell in Debian, on Suday at 15:30. I hope it will be useful to Debian users (who will better understand the packaging), other Debian Developers (who’ll learn about the peculiarities of Haskell and the implications for the Debian infrastructure), other distro’s maintainers (to compare best practices) and Haskell developers (to learn about the needs and worries of downstream packages). The talk will be based on my DebConf 11 talk on the same topic. I’m also happy to answer questions about Haskell, Haskell in Debian or any other topic that you want to hear my opinion about, so just talk to me during FOSDEM.

In related news: GHC 7.6.2 was uploaded to Debian experimental the day it was released; the rebuilding of all libraries is still in progress (~370 of ~570 done).




Creating a Debian source package without unpacking the source

Sat, 13 Oct 2012 13:03:46 Z

There may be a situation where you want to create a Debian source package without having to unpack the upstream source. One case is where you store your debian/ directory in a version control system of its own and to build your package, you pass the .dsc file to a tool like pbuilder or some remote builder. Now a modern debian source package is just a text file (the .dsc file) that references two tarballs, one being the upstream source and the other being the Debian directory. Thanks to Niels Thykier on #debian, I found the magic invocation of dpkg-source that allows you to create the .dsc directly from the two tarballs, the control file and the changelog:

> apt-get source --download-only -t experimental haskell-mtl
Reading package lists... Done
Building dependency tree       
Reading state information... Done
NOTICE: 'haskell-mtl' packaging is maintained in the 'Darcs' version control system at:
http://darcs.debian.org/darcs/pkg-haskell/haskell-mtl
Need to get 18.8 kB of source archives.
Get:1 http://http.debian.net/debian/ experimental/main haskell-mtl 2.1.2-1 (dsc) [1616 B]
Get:2 http://http.debian.net/debian/ experimental/main haskell-mtl 2.1.2-1 (tar) [13.7 kB]
Get:3 http://http.debian.net/debian/ experimental/main haskell-mtl 2.1.2-1 (diff) [3509 B]
Fetched 18.8 kB in 0s (22.3 kB/s)    
Download complete and in download only mode
> cp ./haskell-mtl_2.1.2-1.dsc ./haskell-mtl_2.1.2-1.dsc-orig
> tar xzf haskell-mtl_2.1.2-1.debian.tar.gz
> dpkg-source -cdebian/control -ldebian/changelog --format="3.0 (custom)" --target-format="3.0 (quilt)" -b / haskell-mtl_2.1.2.orig.tar.gz haskell-mtl_2.1.2-1.debian.tar.gz
dpkg-source: info: using source format `3.0 (custom)'
dpkg-source: info: building haskell-mtl in haskell-mtl_2.1.2-1.dsc
> diff  -u haskell-mtl_2.1.2-1.dsc haskell-mtl_2.1.2-1.dsc-orig
--- haskell-mtl_2.1.2-1.dsc	2012-10-13 15:09:00.031695856 +0200
+++ haskell-mtl_2.1.2-1.dsc-orig	2012-10-13 15:08:47.267696329 +0200
@@ -1,3 +1,6 @@
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
 Format: 3.0 (quilt)
 Source: haskell-mtl
 Binary: libghc-mtl-dev, libghc-mtl-prof, libghc-mtl-doc
@@ -23,3 +26,11 @@
 Files: 
  943c110524d96126bfa0e61f7df1ebcd 13723 haskell-mtl_2.1.2.orig.tar.gz
  dda5ded58a8d009ecddeed68058ca787 3509 haskell-mtl_2.1.2-1.debian.tar.gz
+
+-----BEGIN PGP SIGNATURE-----
+Version: GnuPG v1.4.12 (GNU/Linux)
+
+iEYEARECAAYFAlBzRQIACgkQ9ijrk0dDIGwymwCfW87jwCv5ZvAXPBwh0LbvYLP9
+n+wAn3TCJwPRuBDEWRYmcv3Opn1Kb9+F
+=/Llc
+-----END PGP SIGNATURE-----

As you can see, the resulting .dsc file is identical to the original one, so this approach works. The parameter to -b does not matter as long as it is some existing directory. Of course you can easily shoot yourself and others in the foot, almost as easily as hand-editing the .dsc file... but if you know what you are doing, then this can be quite handy.

Next to do: Write a tool that takes an unpacked Debian directory as an argument, packs it, finds the original tarball using uscan and creates the .dsc file. Would this be something that people would want in the devscripts package?




10 years of using Debian

Sat, 12 May 2012 10:00:00 Z

Today, it must have been exactly 10 years that I started using Debian. The story of how I came to Debian shows some of its strengths, so I’ll use this occasion to share it.

I spent the first half of 2002 as an high-school exchange student in Wenatchee, USA. I was already a user of Linux at that time: I made my first contact roughly in 1996 and did my first installation at home two years later, but all that time I was dual-booting and my main system was a well-arranged Windows 98. The machine was a regular tower PC, but nevertheless I put the computer into my trunk when I flew to the US. It took away most of the space, and I had to put some of my cloths inside the case.

So I was there, happily using my Windows and my manually set up “Linux From Scratch” until one day the inevitable happened; inevitable at least until you start doing backups: On April 30th, my hard drive crashed, and took the two systems together with 4 years of personal data with it.

Two weeks later I had a new hard drive and was pondering my options. I did plan to install Windows again; at that time Windows XP was just released. But I wanted a German version of Windows, which would be hard to get there. Also, I did not want to use Linux from Scratch any more, and wanted to make a well-founded choice of a distribution. On the other hand, I really wanted to get my machine up and running quickly, to be able to read my mail more comfortably. I had heard that Debian had good support for network installations (downloading a full 700MB CD was something to avoid at that time), so I grabbed some netinst images, burned a CD, and quickly installed Debian.

I was planning to use the system for about two weeks. I did not pay any particular attention to the setup. Heck, I even picked from my Simpsons sidekick machine naming scheme one that I would not miss being used up (“barney”). Nevertheless, I was using this installation for many years (and many upgrades), until I eventually switched to using laptops. In fact, that very installation is still on the machine somewhere and works. I did install Windows XP a few weeks later as well, but hardly used it. So May 12th of 2002 was when I turned into a full-time Linux and Debian user.

I soon became interested in Debian the project and started to contribute. But that is another story for another ten year anniversary blog post, most likely on October 21, 2013...




Some late recognition of metainit

Sat, 03 Dec 2011 21:19:11 Z

Four years ago, during DebConf 7 in Edinburgh, I had the idea of creating init scripts not by hand, but rather describe them in a declarative way that handles most common cases and generate the real init scripts from them. Back than, this was partly motivated by the varying quality of init scripts and the advent of an alternative init system, upstart, for which proper service files could be generated as well.

I implemented the idea and uploaded it as metainit to Debian, but it did not take off. Only one package uses it, and this package is not used much either. The project basically fell dormant.

Yesterday, I got this mail:

Hi Joachim,

I'm not very familiar with Debian ecosystem, however our company has recently switched to exclusively using Debian based servers, please forgive me if there exists a better channel for sending patches.

We need (in house) to create a lot of trivial services and the sysv init system seems an ideal way to manage them, and metainit an great way to keep the config simple.

However all our scripts require a heartbeat, the way we normally do this is with a bunch of checkers launched from cron. Metainit was ideal, but lacked the simple 'status' task found in most init scripts.

This small patch adds that task, I hope you and others find it usefull.

Regards,

together with the mentioned patch. So it turned out that the idea was a useful one after all, although it found its use on our user’s machines, and not within the Debian packages, as I originally anticipated. Nice!

During the recent discussions about the latest init system, systemd, there were more thoughts about generating init scripts/upstart service descriptions/systemd units from a declarative description, and if metainit had taken off back then, things would be easier now. So if anyone feels like reviving the project: Please do.




Help wanted maintaining link-monitor-applet

Sat, 15 Oct 2011 14:16:47 Z

Jean-Yves Lefort’s link-monitor-applet, an applet for the GNOME panel, is a great tool for those with often-changing and possibly unreliable network connection. It allows me to see, at one glance, whether I can reach the router, the internet and/or my VPN. Furthermore, the latency display tells me whether there is a point in working over SSH right now. I often observe other people, e.g. on conferences, to stare for a while at a non-loading web page, then fire up a terminal window and run random ping commands, while I immediately see that the network is down and can relax.

(image)

Unfortunately, Jean-Yves seems to have stopped working on link-monitor-applet and does not reply to bug reports. This was not a big deal as long as I could use the last released version with minor patches of mine, but now gnome-panel 3 is coming up and all applets need porting to GTK3. Yesterday and today I worked on that, and got it so far that the applet is fully functional, although the visual styling is not perfect yet, because I’m not sure how to do what Jean-Yves did with GtkStyle and GdkGC now with GtkStyleContext and Cairo. The code is in the gnome3 branch of my git repository.

For this issue, and any further maintenance work, I’m looking for someone who is willing to take upstream responsibility for link-monitor-applet, e.g. making sure it works with the latest GNOME (well, GNOME in fallback mode) and that bug reports are handled. The code base is not too big, and both the non-standard build system and the gob-enhanced C code are fine to work with. I’ll still be happy to serve as the maintainer of the Debian package of link-monitor-applet.




Yesod packaged for Debian

Sun, 25 Sep 2011 20:39:04 Z

As Clint writes on his blog, we have now Yesod, a Haskell web framework, packaged in Debian. Despite his humble choice of words, it was mostly his work, and it is quite some work, given that Yesod has a huge number of dependencies that were not yet packaged.

So if you want to use Yesod on Debian, and prefer pre-built libraries without dependency problems and clean installation/deinstallation with dpkg over having always latest and greatest, this should provide you with a solid base.




SAT-solving the testing transition problem

Tue, 26 Jul 2011 09:23:35 Z

It is half-time for me at DebCamp/DebConf11 in Banja Luka, Bosnia-Herzegovina, and that is a good time to write about my work so far. I started with some finger exercises, such as the HTML copying for gnome-terminal (as blogged previously) and cosmetic changes to the buildd.debian.org/status website. After that, I began my main project: A SAT-based solver for the testing transition problem. In Debian, new software first enters a repository called unstable, where it is tested. Once some requirements are fulfilled (package has been in unstable for usually at least 10 days and has no new release critical bugs), it is entitled to enter the repository called testing, which will eventually form a new stable Debian release. But some packages need to migrate together, usually because either requires the new version of the other. Also, no packages in testing ought to become uninstallable by some seemingly unrelated change. The software that decides these things is called britney. It is sufficiently good in making sure nothing bad happens, but not smart enough to figure out what to do in case more than two packages need to migrate simultaneously. My goal is to improve this. Now, the the various requirements can all be expressed as predicative formulas, and a lot of research has been going into writing good solvers for such problems, called SAT-solvers. Hence my plan was to only specify what we expect from a testing migration, but leave the search for a solution to such a general purpose and highly optimized program. My initial progress was good and I had some result after two days of hacking, and the approach is promising. Because the data sets are pretty large (1.5GB of input data, the final SAT problem has 1.8 million clauses with 250.000 variables), so I learned quite a bit about profiling and optimizing Haskell programs, and that parsec is slower than working with BS.lines and BS.split to parse simple input. I also used the FFI to use dpkg code directly to compare Debian version numbers. At some point I noticed that I actually want to solve PMAX-SAT problems: Given two set of clauses, hard clauses and soft clauses, find a variable assignment that fulfills the hard clauses and as many of the soft clauses as possible. Unfortunately, there are no fast Free PMAX-SAT solvers around. The ones that I found and that were fast enough that I could use them, msuncore by Joao Marques-Silva at the University College Dublin and MiniMaxSat by Federico Heras at the Universitat Politècnica de Catalunya, are only available as statically linked binaries. It is a shame that this is acceptable by the academic community; imagine mathematicians would stop including the proofs in their papers, and only share their theorems. So if you happen to have written a PMAX-SAT solver and can solve this instance (in weighted DIMACS format) in less than five minutes, and want to brag that the Debian project is using your code, then please release it under a Free license (e.g. GPL or BSD) and tell me about it! The code of my SAT-based solver is, of course, available, though slightly unpolished. Parts of it (notably the interface to picosat and the PMAX-SAT solvers) might be of general interest and I plan to put them on Hackage as a separate license. Update: I have contacted the authors of the SAT solvers mentioned above, and they have reconfirmed that they have no intention of releasing the source. Now I put my hope in maxsatz2009 by Chumin LI, which is GPL but was not able to cope with my large instance directly; I think I need to change the memory management. [...]



How forky may one maintain a Debian package?

Sat, 17 Jul 2010 19:59:47 Z

I maintain most of my Debian packages because I use them myself. Sometimes, I have some needs that go slightly beyond what is currently offered by the software. This is not a problem: Debian ships Free Software and I can program, therefore I can patch the software to also do what I want it to do. Trying to be a good member of the Free Software community, I then submit the patch to the upstream author. If he accepts the patch (which is usually the case), everything is fine. But what if he does not reply to the report or rejects it because he does not want this feature (although the patch is technically fine)? I see two options:

  1. I could continue to use a privately patched and built version of the package, while separately building packages for Debian. This way, Debian ships the software as intended by the upstream maintainer while I can use the features I need. On the other hand, I would not be using the version that I upload to Debian, which is not good, and it causes double work when a a new version is released.
  2. I could upload a package to Debian that contains my patch. The technical infrastructure to add patch in Debian packages has always been there... I would actually use the package as it is in Debian and only manage one line of versions. But would I be abusing my powers as a Debian maintainer? If I were not the maintainer, I could not make this decision by myself (this happend with my patch to nagstamon). Plus it could have a negative effect on the Debian-upstream relationship.

How do other Debian Developers handle such issues? The actual case I’m considering is a feature enhancement for link-monitor-applet (but I only just wrote the patch, so it does not yet fall in the category “upstream does not reply”).