We have all ran into software inconveniences. These are things that you can basically do but for some reason or another are unintuitive, hard or needlessly complex. When you air your concerns on these issues, sometimes they get fixed. At other times you get back a reply starting with “Well in general you may have a point, but …”.

The rest of the sentence is something along the lines of these examples:

“… you only have to do it once so it’s no big deal.”
“… there are cases where [e.g. autodetection] would not work so having the user [manually do task X] is the only way to be reliable.”
“… I don’t see any problem, in fact I like it the way it is.”
“… replacing [the horrible thing in question] with something better is too much work.”
“… fixing that would change things and change is bad.”
“… that is the established standard way of doing things.”
“… having a human being write that in is good, it means that the input is inspected.”

These are all fine and acceptable reasonings under certain circumstances. In fact, they are great! Let’s see what life would be like in a parallel universe where people had followed them slavishly.

Booting Linux: an adventure for the brave

You arrive to your work computer and turn it on. The LILO boot prompt comes up as usually. You type in the partition you want to boot from. This you must do every time because you might have changed partition settings and thus make LILO go out of sync. You type in your boot stanza sure in the knowledge that you get 100% rock solid boot every time.

Except when you have a typo in your boot command but a computer can’t work around that. And that happens only rarely anyways and why would you boot your computer more than once per month?

Once the kernel has loaded, you type in the kernel modules you need to use the machine. You also type in all extra parameters those modules require because some chipsets may work incorrectly sometimes (or so you have been told). So you type in some dozen strings of hexadecimal numbers and really enjoy it in a stockholmesque way.

Finally all the data is put in and the system will boot itself. Then it is time to type in your network settings. In this universe there is no Protocol to Configure network Host settings Dynamically. And why would there be? Any bug in such a system would render the entire network unusable. No, the only way to ensure that things work is to configure network settings by hand every time. Errors in settings cause only one machine to break, not the entire network. Unless you mix gateway/netmask/IP addresses but surely no-one is that stupid? And if they are, it’s their own damn fault! Having things fail spectacularly is GOOD because it shames people into doing the right thing.

After this and a couple of other simple things (each of which you only need to do once, remember) you finally have a working machine. You log on.

Into a text console, naturally. Not all people need X so it should not be started by default. Resources must be used judiciously after all.

But you only need to start X once per session so no biggie. Just like you only need to write in your monitor modeline once per X startup because autodetection might fail and cause HW failure. The modeline can not be stored in a file and used automatically because you might have plugged in a different monitor. Typing it in every time is the only way to be sure. Or would you rather die horribly in a fire caused by incorrect monitor parameters?

After all that is done you can finally fire up an XTerm to start working. But today you feel like increasing the font size a bit. This is about as simple as can get. XTerm stores a list of font sizes it will display in XResources. All you have to do is to edit them, shut down X and start it up again.

Easy as pie. And the best part: you only have to do this once.

Well, once every time you want to add new font sizes. But how often is that, really?

Summary

The examples listed above are but a small fraction of reality. If computer users had to do all “one time only” things, they would easily take the entire eight hour work day. The reason they don’t is that some developer Out There has followed this simple rule:

Almost every task that needs to be done “one time only” should, in fact, be done exactly zero times.

ZERO!

I just released a new PyGObject, for GNOME 3.7.4 which is due on Wednesday.

This release saw a lot of bug and memory leak fixes again, as well as enabling some more data types such as GParamSpec, boxed list properties, or directly setting string members in structs.

Thanks to all contributors!

Summary of changes (see change log for complete details):

• Allow setting values through GtkTreeModelFilter (Simonas Kazlauskas) (#689624)
• Support GParamSpec signal arguments from Python (Martin Pitt) (#683099)
• pygobject_emit(): Fix cleanup on error (Martin Pitt)
• Add signal emission methods to TreeModel which coerce the path argument (Simon Feltman) (#682933)
• Add override for GValue (Bastian Winkler) (#677473)
• Mark caller-allocated boxed structures as having a slice allocated (Mike Gorse) (#699501)
• pygi-property: Support boxed GSList/GList types (Olivier Crête) (#684059)
• tests: Add missing backwards compat methods for Python 2.6 (Martin Pitt) (#691646)
• Allow setting TreeModel values to None (Simon Feltman) (#684094)
• Set clean-up handler for marshalled arrays (Mike Gorse) (#691509)
• Support setting string fields in structs (Vadim Rutkovsky) (#678401)
• Permit plain integers for “gchar” values (Martin Pitt)
• Allow single byte values for int8 types (Martin Pitt) (#691524)
• Fix invalid memory access handling errors when registering an enum type (Mike Gorse)
• Fix (out) arguments in callbacks (Martin Pitt)
• Fix C to Python marshalling of struct pointer arrays (Martin Pitt)
• Don’t let Property.setter() method names define property names (Martin Pitt) (#688971)
• Use g-i stack allocation API (Martin Pitt) (#615982)
• pyg_value_from_pyobject: support GArray (Ray Strode) (#690514)
• Fix obsolete automake macros (Marko Lindqvist) (#691101)
• Change dynamic enum and flag gtype creation to use namespaced naming (Simon Feltman) (#690455)
• Fix Gtk.UIManager.add_ui_from_string() override for non-ASCII chars (Jonathan Ballet) (#690329)
• Don’t dup strings before passing them to type registration functions (Mike Gorse) (#690532)
• Fix marshalling of arrays of boxed struct values (Carlos Garnacho) (#656312)
• testhelpermodule.c: Do not unref called method (Martin Pitt)

Using libraries in C++ is simple. You just do #include<libname> and all necessary definitions appear in your source file.

But what is the cost of this single line of code?

Quite a lot, it turns out. Measuring the effect is straightforward. Gcc has a compiler flag -E, which only runs the preprocessor on the given source file. The cost of an include can be measured by writing a source file that has only one command: #include<filename>. The amount of lines in the resulting file tells how much code the compiler needs to parse in order to use the library.

Here is a table with measurements. They were run on a regular desktop PC with 4 GB of RAM and an SSD disk. The tests were run several times to insure that everything was in cache. The machine was running Ubuntu 12/10 64 bit and the compiler was gcc.

Header                     LOC    Time

map                       8751    0.02
unordered_map             9728    0.03
vector                    9964    0.02
Python.h                 11577    0.05
string                   15791    0.07
memory                   17339    0.04
sigc++/sigc++.h          21900    0.05
boost/regex.h            22285    0.06
iostream                 23496    0.06
unity/unity.h            28254    0.14
xapian.h                 36023    0.08
algorithm                40628    0.12
gtk/gtk.h                52379    0.26
gtest/gtest.h            53588    0.12
boost/proto/proto.hpp    78000    0.63
gmock/gmock.h            82021    0.18
QtCore/QtCore            82090    0.22
QtWebKit/QtWebKit        95498    0.23
QtGui/QtGui             116006    0.29
boost/python.hpp        132158    3.41
Nux/Nux.h               158429    0.71

It should be noted that the elapsed time is only the amount it takes to run the code through the preprocessor. This is relatively simple compared to parsing the code and generating the corresponding machine instructions. I ran the test with Clang as well and the times were roughly similar.

Even the most common headers such as vector add almost 10k lines of code whenever they are included. This is quite a lot more than most source files that use them. On the other end of the spectrum is stuff like Boost.Python, which takes over three seconds to include. An interesting question is why it is so much slower than Nux, even though it has less code.

This is the main reason why spurious includes need to be eliminated. Simply having include directives causes massive loss of time, even if the features in question are never used. Placing a slow include in a much used header file can cause massive slowdowns. So if you could go ahead and not do that, that would be great.

A long time ago in the dawn of the new millennium lived a man. He was working as a software developer in a medium sized company. His life was pretty good all things considered. For the purposes of this narrative, let us call him Junior Developer.

At his workplace CVS was used for revision control. This was okay, but every now and then problems arose. Because it could not do atomic commits, sometimes two people would check in things at the same time, which broke everything. Sometimes this was immediately apparent and caused people to scramble around to quickly fix the code. At other times the bugs would lay dormant and break things at the worst possible times.

This irritated everyone but since the system mostly worked, this was seen as an unfortunate fact of life. Then Junior Developer found out about a brand new thing called Subversion. It seeemed to be just the thing they needed. It was used in almost exactly the same way, but it was so much better. All commits were atomic, which made mixing commits impossible. One could even rename files, a feature thus far unheard of.

This filled the heart of Junior Developer with joy. With one stroke they could eliminate most of their tooling problems and therefore improve their product’s quality. Overjoyed he waited for the next team meeting where they discussed internal processes.

Once the meeting started, the Junior Developer briefly reminded people of the problems and then explained how Subversion would fix most of the problems that CVS was causing.

At the other end of the table sat a different kind of man, who we shall call the Senior Developer. He was a man of extraordinary skill. He had personally designed and coded many of the systems that the company’s products relied on. Whenever anyone had a difficult technical issue, he would go ask the Senior Developer. His knowledge on his trade had extensive depth and breadth.

Before anyone else had time to comment on the Junior Developer’s suggestion, he grabbed the stage and let out a reply in a stern voice.

- This is not the sort of discussion we should be getting into. CVS is good and we’ll keep using it. Next issue.

The Junior Developer was shocked. He tried to form some sort of a reply but words just refused to come out of his mouth. Why was his suggestion for improvement shot down so fast? Had someone already done a Subversion test he had not heard about? Had he presented his suggestion too brazenly and offended the Senior Developer? What was going on?

These and other questions raced around in his head for the next few days. Eventually he gathered enough willpower and approached the Senior Developer during a coffee break.

- Hey, remember that discussion on Subversion and CVS we had a few days ago? Why did you declare it useless so quickly? Have you maybe tried it and found it lacking?

- I figured you might mention this. Look, I’m sure you are doing your best but the fact of the matter is that CVS is a good tool and it does everything we want it to do.

- But that’s just the thing. It does not do what we want. For example it does not have atomic commits. It would prevent check-in conflicts.

The Senior Programmer lifted his coffee cup to his lips and took a swig. Not to play for time, but simply to give emphasis to his message.

- CVS is a great tool. You just have to be careful when using it and problems like this don’t happen.

The Junior Programmer then tried to explain that even though they were being careful, breakages still happened and they had been for as long as anyone could remember. He tried explaining that in Subversion one could rename files and retain their version control history. He tried to explain how these and other features would be good, how they would allow for developers to spend more of their time on actual code and less on working around features of their tools.

The Senior Developer countered each of these issues with one of two points. Number one was the fact that you could achieve roughly the same with CVS if that is really what was wanted (with an unspoken but very clear implication that it was not). Number two was that functionality such as renames could be achieved by manually editing the repository files. This was considered a major plus, since one would not be able to do this kind of maintenance work on Subversion repositories because they were not plain text files. Any database runs the risk of corruption, which was unacceptable for something as important as source code.

The discussion went on but eventually the Senior Developer had finished his coffee and walked over to the dishwasher to put his cup away.

- Look, I appreciate the thinking you have obviously put into this but let me tell you a little something.

He put his cup away and turned to face the Junior Developer who at this point was majorly frustrated.

- I have used CVS for over 10 years. It is the best system there is. In this time there have been dozens of revision control systems that claim to have provided the same benefits that this Subversion of yours does. I have tried many of them and none have delivered. Some have been worse than the systems CVS replaced if you can believe that. The same will happen with Subversion. The advantages it claims to provide simply are not there, and that’s the sad truth.

The Junior Developer felt like shouting but controlled himself realizing that no good thing could come out of losing his temper. He slouched in his chair. The Senior Developer looked at the clearly disillusioned Junior Developer and realized the argument had ended in his favor. He left back to his office.

At the coffee room door he turned around and said his final words to the Junior Developer.

- Besides, even if the atomic commits you seem to hold so dear would work, the improvements they provide would be minimal. They are a nice-to-have toy and will never account for anything more than that.

Epilogue

This story is not true. But it could be.

Variants of this discussion are being held every single day in software development companies and communities around the world.

I just released a new PyGObject, for GNOME 3.7.3 which is due on Wednesday.

This is mostly a bug fix release. There is one API addition, it brings back official support for calling GLib.io_add_watch() with a Python file object or fd as first argument, in addition to the official API which expects a GLib.IOChannel object. These modes were marked as deprecated in 3.7.2 (only).

Thanks to all contributors!

Summary of changes (see change log for complete details):

• Add support for caller-allocated GArray out arguments (Martin Pitt) (#690041)
• Re-support calling GLib.io_add_watch with an fd or Python file (Martin Pitt)
• pygtkcompat: Work around IndexError on large flags (Martin Pitt)
• Fix pyg_value_from_pyobject() range check for uint (Martin Pitt)
• Fix tests to work with g-i 1.34.2 (Martin Pitt)
• Fix wrong refcount for GVariant property defaults (Martin Pitt) (#689267)
• Fix array arguments on 32 bit (Martin Pitt)
• Add backwards compatible API for GLib.unix_signal_add_full() (Martin Pitt)
• Drop MININT64/MAXUINT64 workaround, current g-i gets this right now (Martin Pitt)
• Fix maximum and minimum ranges of TYPE_(U)INT64 properties (Simonas Kazlauskas) (#688949)
• Ship pygi-convert.sh in tarballs (Martin Pitt) (#688697)
• Various added and improved tests (Martin Pitt)

When writing system integration tests it often happens that I want to mount some tmpfses over directories like /etc/postgresql/ or /home, and run the whole script with an unshared mount namespace so that (1) it does not interfere with the real system, and (2) is guaranteed to clean up after itself (unmounting etc.) after it ends in any possible way (including SIGKILL, which breaks usual cleanup methods like “trap”, “finally”, “def tearDown()”, “atexit()” and so on).

In gvfs’ and postgresql-common’s tests, which both have been around for a while, I prepare a set of shell commands in a variable and pipe that into unshare -m sh, but that has some major problems: It doesn’t scale well to large programs, looks rather ugly, breaks syntax highlighting in editors, and it destroys the real stdin, so you cannot e. g. call a “bash -i” in your test for interactively debugging a failed test.

I just changed postgresql-common’s test runner to use unshare/tmpfses as well, and needed a better approach. What I eventually figured out preserves stdin, $0, and $@, and still looks like a normal script (i. e. not just a single big string). It still looks a bit hackish, but I can live with that:

#!/bin/sh
set -e
# call ourselves through unshare in a way that keeps normal stdin, $0, and CLI args
unshare -uim sh -- -c "`tail -n +7 $0`" "$0" "$@"
exit $?

# unshared program starts here
set -e
echo "args: $@"
echo "mounting tmpfs"
mount -n -t tmpfs tmpfs /etc
grep /etc /proc/mounts
echo "done"

As Unix/Linux’ shebang parsing is rather limited, I didn’t find a way to do something like

#!/usr/bin/env unshare -m sh

If anyone knows a trick which avoids the “tail -n +7″ hack and having to pay attention to passing around “$@”, I’d appreciate a comment how to simplify this.

Software quality has received a lot of attention recently. There have been tons of books, blog posts, conferences and the like on improving quality. Tools and practices such as TDD, automatic builds, agile methods, pair programming and static code analysers are praised for improving code quality.

And, indeed, that is what they have done.

But one should never mix the tool with the person using it. All these wonderful tools are just that: tools. They are not the source of quality, only facilitators of it. The true essence of quality does not flow from them. It comes from somewhere else entirely. When distilled down to its core, there is only one source of true quality.

Caring.

The only way to get consistently high quality code is that the people who generate it care about it. This means that they have a personal interest in their code tree. They want it to succeed and flourish. In the best case they are even proud of it. This is the foundation all quality tools lie on.

If caring does not exist, even the best of tools can not help. This is due to the fact that human beings are very, very good at avoiding work they don’t want to do. As an example, let’s look at code review. A caring person will review code to the best of their abilities because he wants the end result be the best it can be. A non-caring one will shrug, think “yeah, sure, fine, whatever” and push the accept button, because it’s less work for him and he knows that his merge requests will go in easier if there is a general (though unspoken) consensus of doing things half-assed.

Unfortunately caring is not something you can buy, it is something you must birth. Free food and other services provided by companies such as Valve and Google can be seen as one way of achieving quality. If a company sincerely cares about its employees, they will in return care about the quality of their work.

All that said, here is my proposal for a coder’s mascot:

I just released Apport 2.7.

The main new feature is supporting foreign architectures in apport-retrace. If apport-retrace works in sandbox mode and works on a crash that was not produced on the same architecture as apport-retrace is running on, it will now build a sandbox for the report’s architecture and invoke gdb with the necessary magic options to produce a proper stack trace (and the other gdb information).
Right now this works for i386, x86_64, and ARMv7, but if someone is interested in making this work for other architectures, please ping me.

This is rolled out to the Launchpad retracers, see for example Bug #1088428. So from now on you can report your armhf crashes to Launchpad and they ought to be processed. Note that I did a mass-cleanup of old armhf crash bugs this morning, as the existing ones were way too old to be retraced.

For those who are running their own retracers for their project: You need to add an armhf specific apt sources list your per-release configuration directory, e. g. Ubuntu 12.04/armhf/sources.list as armhf is on ports.ubuntu.com instead of archive.ubuntu.com. Also, you need to add an armhf crash database to your crashdb.conf and add a cron job for the new architecture. You can see how all this looks like in the configuration files for the Launchpad retracers.

The other improvement concerns package hooks. So far, when a package hook crashed the exception was only printed to stderr, where most people would never see them when using the GTK or KDE frontend. With 2.7 these exceptions are also added to the report itself (HookError_filename), so that they appear in the bug reports.

The release also fixes a couple of bugs, see the release notes for details.

I do a lot of cross compilations. With different software elements. But sometimes I want to kick their authors into ass…

There is a good sign when you see $(CC) in Makefiles as it shows that author of code learnt that “gcc” is not the only compiler. But this is not the only compiler you should know about.

Recently I was adding one component (will save a name) into OpenEmbedded as this is one of dependencies for some bigger project (which I do not want to blog about). Argh… I managed to cross built it but patches are UGLY (will get better).

Using $(CC) to build everything is just broken. Especially when you need to compile a tool which will generate some code to get everything built. There is $(BUILD_CC) for it but you have to use it wisely. If there are common parts then compile them with $(BUILD_CC) if you need to run it and with $(CC) if you not. This way we, cross compilation guys, can just do “./configure;make;make install;package” is it native or cross build. Autotools (die, die, die) are able to handle that — so is your code if you write Makefiles properly.

But do not reuse same object files for target and native binaries — let it be “common.o” and “native/common.o” for example. OK, if you do only native builds then it will take a bit more disk space but we have 2012 not 1995… Storage is cheap.

There is also $(HOST_CC) but that’s for other post…

All rights reserved © Marcin Juszkiewicz
There are other compilers than $(CC) was originally posted on Marcin Juszkiewicz website

We have achieved a huge milestone in the development community. For years we wanted translatable packaging and development documentation. It’s there. If you head to http://developer.ubuntu.com/packaging/ you can see the following:

The Ubuntu Packaging Guide (Spanish) – would you like to learn how to package or become an Ubuntu Developer? Here’s a comprehensive, topic-base guide that explores and describes the main concepts of packaging. It is available as

• a single HTML page (Spanish),
• a PDF document (Spanish), or
• in EPUB format (for eBook readers) (Spanish).

This is absolutely awesome. From now on we will be able to add languages and have up-to-date Packaging and Development docs available whenever they are complete enough.

This work was brought to you by many people who worked very hard to get all the bits right, both on the packaging, integration, beautification and translations sides. You all know who you are. Be proud of your work. This will ease the steps of many people into helping out with Ubuntu!

As always this is ongoing work and the great thing is, you can help out:

• Fix bugs and improve the guide.
• Translate the guide.
• File bugs on the guide.

This makes me a very happy man and it’s great we finally got there. Now let’s get all the other translations up to scratch!

Every day computer users do a variation of a simple task: selecting an element from a list of choices. Examples include installing packages with ‘apt-get install packagename’, launching an application from the Dash with its name, selecting your country from a list on web pages and so on.

The common thing in all these use cases is intolerance for errors. If you have just one typo in your text, the correct choice will not be found. The only way around is to erase the query and type it again from scratch. This is something that people have learned to do without thinking.

It’s not very good usability, though. If the user searches for, say, Firefox by typing “friefox” by accident, surely the computer should be able to detect what the user meant and offer that as an alternative.

The first user-facing program in Ubuntu to offer this kind of error tolerance was the HUD. It used the Levenshtein distance as a way of determining user intent. In computer science terminology this is called approximate string matching or, informally, fuzzy matching.

Once the HUD was deployed, the need to have this kind of error correction everywhere became apparent. Thus we sent out to create a library to make error tolerant matching easy to embed. This library is called libcolumbus.

Technical info

Libcolumbus has been designed with the following goals in mind:

• it must be small
• it must be fast
• it must be easy to embed
• it is optimized for online typing

The last of these means that you can do queries at any time, even if the user is still typing.

At the core of libcolumbus is the Levenshtein distance algorithm. It is a well known and established way of doing fuzzy matching. Implementations are used in lots of different places, ranging from heavy duty document retrieval engines such as Lucene and
Xapian all the way down to Bash command completion. There is even a library that does fuzzy regexp matching.

What sets Columbus apart from these are two things, both of which are well known and documented but less often used: a fast search implementation and custom errors.

The first feature is about performance. The fast Levenshtein implementation in libcolumbus is taken almost verbatim from this public domain implementation. The main speedup comes from using a trie to store the words instead of iterating over all items on every query. As a rough estimate, a brute force implementation can do 50-100 queries a second with a data set of 3000 words. The trie version can do 600 queries/second on a data set of 50000 words.

The second feature is about quality of results. It is best illustrated with an example. Suppose there are two items to choose from, “abc” and “abp”. If the user types “abo”, which one of these should be chosen? In the classical Levenshtein sense both of the choices are identical: they are one replace operation away from the query string.

However from a usability point of view “abp” is the correct answer, because the letter p is right next to the letter o and very far from the letter c. The user probably meant to hit the key o but just missed it slightly. Libcolumbus allows you to set custom errors for these
kinds of substitutions. If the standard substitution error is 100, one could set the error for substitution error for adjacent keys to a smaller value, say 20. This causes words with “simple typos” to be ranked higher automatically.

There are several other uses for custom errors:

• diacritical characters such as ê, é and è can be mapped to have very small errors to each other
• fuzzy number pad typing can be enabled by assigning mapping errors from the number to corresponding letters (e.g. ’3′ to ‘d’, ‘e’ and ‘f’) as well as adjacent letters (i.e. those on number keys ’2′ and ’6′)
• spam can be detected by assigning low errors for letters and numbers that look similar, such as ’1′ -> ‘i’ and ’4′ -> ‘a’ to match ‘v14gr4′ to ‘viagra’

Libcolumbus contains sample implementations for all these except for the last one. It also allows setting insert and delete errors at the beginning and end of the match. When set to low values this makes the algorithm do a fuzzy substring search. The online matching discussed above is implemented with this. It allows the library to match the query term “fier” to “firefox” very fast.

Get the code

Our goal for the coming cycle is to enable error tolerant matching in as many locations as possible. Those developers who wish to try it on their application can get the source code here.

The library is implemented in C++0x. The recommended API to use is the C++ one. However since many applications can not link in C++ libraries, we also provide a plain C API. It is not as extensive as the C++ one, but we hope to provide full coverage there too.

The main thing to understand is the data model. Libcolumbus deals in terms of documents. A document consists of a (user provided) document ID and a named collection of texts. The ID field is guaranteed to be large enough to hold a pointer. Here’s an example of what a document could look like:

id: 42
  name: packagename
  description: This package does something.

Each line is a single word field name followed by the text it contains. A document can contain an arbitrary number of fields.  This is roughly analogous to what MongoDB uses. It should be noted that libcolumbus does not read any data files. The user needs to create document objects programmatically. The example above is just a visualisation.

When the documents are created and passed to the main matcher object for processing, the system is ready to be queried. The result of queries is a list of document IDs and corresponding relevancies. Relevancy is just a number whose meaning is roughly “bigger relevancy means better”. The exact values are arbitrary and may change even between queries. End-user applications usually don’t need to bother with them.

There is one thing to be mindful, though. The current implementation has a memory backend only. Its memory usage is moderate but it has not yet been thoroughly optimized. If your data set size is a few hundred unique words, you probably don’t have to care. A few thousand takes around 5 MB which may be a problem in low memory
devices. Tens of thousands of words take tens of megabytes which may be too much for many use cases. Both memory optimizations and a disk backend are planned but for now you might want to stick to smallish data sets.

Our Ubuntu Development Hangouts have had guests every now and then, but we wanted to get more people on board to talk about what’s going on in Ubuntu development. Many of our viewers asked for more detailed information about specific topics.

So here’s what we’re up to in the next weeks (we’ll add more dates and more sessions):

• 4th Dec 2012, 15:00 UTC: Rick Spencer, Vice President of Ubuntu Engineering at Canonical will talk to us about 13.04 and the great things which are coming.
• 11 Dec 2012, 16:00 UTC: Iain Lane, Ubuntu and Debian Developer will chat with us about desktop stuff, motu stuff, release team, backports and all that jazz.
• 13 Dec 2012, 9:00 UTC: Didier Roche, Unity+Desktop hacker, Unity progress in 13.04, daily builds, automated tests.
• 18 Dec 2012, 16:00 UTC: Chris Wilson, One Hundred Paper Cuts Team Lead will talk about the One Hundred Paper Cuts project, what the project does and how to get involved.

This guy will be part of the fun as well.

I created a project at Launchpad to have one place to gather hackers playing with ARM based Chromebook support in their distros.

Project is named “Cross distro support for Samsung Chromebook (ARM based)” and is maintained by team named “Samsung Chromebook (ARM) hackers“. If you want to join then you need to have Launchpad account and then join the team.

Why Launchpad instead of (insert any similar place)? Because I know it and it has very good bugtracker which allows to track other bug trackers. And it does not have to have anything related with Ubuntu…

OK, most of bugs now are about Ubuntu but that’s because I added them. But take a look at bug about ALSA UCM support. It affects our project but also affected “alsa-lib” and “alsa-utils” packages in Ubuntu. There is nothing which could stop us from adding links to Debian, Fedora, OpenSUSE or other distros bug reports there.

I added PPA there which will get binary packages for “raring” (unless they got merged) and backports for “quantal” and who knows, maybe one day even for “precise”. Due to policy that repository will not be able to build for “armhf” architecture but one of my personal ones can so I will copy packages.

So, who wants to join us? We already have non-Ubuntu people in the team!

All rights reserved © Marcin Juszkiewicz
Chromebook hackers: unite! was originally posted on Marcin Juszkiewicz website

During last days I spent some time in binutils, gcc, gdb, glibc, libffi repositories. All of them have GIT mirrors but most (if not all) are kept in CVS by default.

I used CVS in previous millenium just because I did not know good alternative. But I also know that move from it to other SCM can be painful.

But digging though commits because shortlog view is useless hurts… Exported patches need to be edited to drop all changes to many Changelog files. For libffi it is even better to grab patches from mailing list than from repository…

Life sucks, then you die^Whave to deal with CVS git repos.

All rights reserved © Marcin Juszkiewicz
I hate CVS based repositories was originally posted on Marcin Juszkiewicz website

Half year ago I got Tizen development platform device. Played a bit with it and then put in a drawer due to other things to do.

Today I looked again at Tizen. Nothing changed. Git repositories still scream “****@#$!$ *** *** you developers!” due to lack of any commits other than code drop bombs.

So if someone (from Europe) wants this device — be first to comment. Sending with DHL and you pay for posting.

All rights reserved © Marcin Juszkiewicz
Does someone wants Tizen development platform device? was originally posted on Marcin Juszkiewicz website

People told me many times that I complain a lot (maybe even too much sometimes). But this is who I am and you have to live with it.

When I get new device I usually blog about it — like I told during recent conferences: “give me a device and I will find something to complain about, but also will usually tell something positive as well”. Sometimes those posts even got presented by other people at management meetings as an example of what is good/wrong in described products.

But so far I never got an email with ask to remove any blog post — there were comments outside of blog sometimes but never request to take my opinion down. I edited two posts — first one was before publication because I sent it for review (it was not requested by company), second time when I got some information about product in public space but device had to be announced week later at big event during one of trade shows.

What do you think? Should I write more about devices or rather not?

All rights reserved © Marcin Juszkiewicz
Complaining was originally posted on Marcin Juszkiewicz website

just released a new PyGObject, for GNOME 3.7.2 which is due on Wednesday.

In this version PyGObject went through some major refactoring: Some 5.000 lines of static bindings were removed and replaced with proper introspection and some overrides for backwards compatibility, and the static/GI/overrides code structure was simplified. For the developer this means that you can now use the full GLib API, a lot of which was previously hidden by old and incomplete static bindings; also you can and should now use the officially documented GLib API instead of PyGObject’s static one, which has been marked as deprecated. For PyGObject itself this change means that the code structure is now a lot simpler to understand, all the bugs in the static GLib bindings are gone, and the GLib bindings will not go out of sync any more.

Lots of new tests were written to ensure that the API is backwards compatible, but experience teaches that ther is always the odd corner case which we did not cover. So if your code does not work any more with 3.7.2, please do report bugs.

Another important change is that if you build pygobject from source, it now defaults to using Python 3 if installed. As before, you can build for Python 2 with PYTHON=python2.7 or the new --with-python=python2.7 configure option.

This release also brings several marshalling fixes, docstring improvements, support for code coverage, and other bug fixes.

Thanks to all contributors!

Summary of changes (see changelog for complete details):

• [API change] Drop almost all static GLib bindings and replace them with proper introspection. This gets rid of several cases where the PyGObject API was not matching the real GLib API, makes the full GLib API available through introspection, and makes the code smaller, easier to maintain. For backwards compatibility, overrides are provided to emulate the old static binding API, but this will throw a PyGIDeprecationWarning for the cases that diverge from the official API (in particular, GLib.io_add_watch() and GLib.child_watch_add() being called without a priority argument). (Martin Pitt, Simon Feltman)
• [API change] Deprecate calling GLib API through the GObject namespace. This has always been a misnomer with introspection, and will be removed in a later version; for now this throws a PyGIDeprecationWarning.
• [API change] Do not bind gobject_get_data() and gobject_set_data(). These have been deprecated for a cycle, now dropped entirely. (Steve Frécinaux) (#641944)
• [API change] Deprecate void pointer fields as general PyObject storage. (Simon Feltman) (#683599)
• Add support for GVariant properties (Martin Pitt)
• Add type checking to GVariant argument assignment (Martin Pitt)
• Fix marshalling of arrays of struct pointers to Python (Carlos Garnacho) (#678620)
• Fix Gdk.Atom to have a proper str() and repr() (Martin Pitt) (#678620)
• Make sure g_value_set_boxed does not cause a buffer overrun with GStrvs (Simon Feltman) (#688232)
• Fix leaks with GValues holding boxed and object types (Simon Feltman) (#688137)
• Add doc strings showing method signatures for gi methods (Simon Feltman) (#681967)
• Set Property instance doc string and blurb to getter doc string (Simon Feltman) (#688025)
• Add GObject.G_MINSSIZE (Martin Pitt)
• Fix marshalling of GByteArrays (Martin Pitt)
• Fix marshalling of ssize_t to smaller ints (Martin Pitt)
• Add support for lcov code coverage, and add a lot of missing GIMarshallingTests and g-i Regress tests. (Martin Pitt)
• pygi-convert: remove deprecated GLib ? GObject conversions (Jose Rostagno)
• Add support for overriding GObject.Object (Simon Feltman) (#672727)
• Add –with-python configure option (Martin Pitt)
• Do not prefer unversioned “python” when configuring, as some distros have “python” as Python 3. Use Python 3 by default if available. Add –with-python configure option as an alternative to setting $PYTHON, whic is more discoverable. (Martin Pitt)
• Fix property lookup in class hierarchy (Daniel Drake) (#686942)
• Move property and signal creation into _class_init() (Martin Pitt) (#686149)
• Fix duplicate symbols error on OSX (John Ralls)
• [API add] Add get_introspection_module for getting un-overridden modules (Simon Feltman) (#686828)
• Work around wrong 64 bit constants in GLib Gir (Martin Pitt) (#685022)
• Mark GLib.Source.get_current_time() as deprecated (Martin Pitt)
• Fix OverflowError in source_remove() (Martin Pitt) (#684526)

With python-dbusmock you can provide mocks for arbitrary D-BUS services for your test suites or if you want to reproduce a bug.

However, when writing actual tests for gnome-settings-daemon etc. I noticed that it is rather cumbersome to always have to set up the “skeleton” of common services such as UPower. python-dbusmock 0.2 now introduces the concept of “templates” which provide those skeletons for common standard services so that your code only needs to set up the particular properties and specific D-BUS objects that you need. These templates can be parameterized for common customizations, and they can provide additional convenience methods on the org.freedesktop.DBus.Mock interface to provide more abstract functionality like “add a battery”.

So if you want to pretend you have one AC and a half-charged battery, you can now simply do

  def setUp(self):
     (self.p_mock, self.obj_upower) = self.spawn_server_template('upower', {})

  def test_ac_bat(self):
     self.obj_upower.AddAC('mock_AC', 'Mock AC')
     self.obj_upower.AddChargingBattery('mock_BAT', 'Mock Battery', 50.0, 1200)

Or, if your code is not in Python, use the CLI/D-BUS interface, like in shell:

  # start a fake system bus
  eval `dbus-launch`
  export DBUS_SYSTEM_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS

  # start mock upower on the fake bus
  python3 -m dbusmock --template upower &

  # add devices
  gdbus call --system -d org.freedesktop.UPower -o /org/freedesktop/UPower \
      -m org.freedesktop.DBus.Mock.AddAC mock_ac 'Mock AC'
  gdbus call --system -d org.freedesktop.UPower -o /org/freedesktop/UPower \
      -m org.freedesktop.DBus.Mock.AddChargingBattery mock_bat 'Mock Bat' 50.0 1200

In both cases upower --dump or gnome-power-statistics will show you the expected devices (of course you need to run that within the environment of the fake $DBUS_SYSTEM_BUS_ADDRESS, or run the mock on the real system bus as root).

Iftikhar Ahmad contributed a template for NetworkManager, which allows you to easily set up ethernet and wifi devices and wifi access points. See pydoc3 dbusmock.templates.networkmanager for details and the test cases for how this looks like in practice.

I just released python-dbusmock 0.2.1 and uploaded the new version to Debian experimental. I will sync it into Ubuntu Raring in a few hours.

I just released PyGObject 3.4.2, a bug fix release for GNOME 3.6.2.

Thanks to all contributors!

• Fix marshalling of GByteArrays (Martin Pitt)
• Fix marshalling of ssize_t to smaller ints (Martin Pitt)
• Fix crash with GLib.child_watch_add (Daniel Narvaez) (#688067)
• Fix various bugs in GLib.IOChannel (Martin Pitt)
• Work around wrong 64 bit constants in GLib Gir (Martin Pitt) (#685022)
• Fix OverflowError in source_remove() (Martin Pitt) (#684526)
• Fix Signal decorator to not use base class gsignals dict (Simon Feltman) (#686496)

It’s time for some Ubuntu Development Events for those of you who are raring to go get started for 13.04 development.

We will be starting the fun today at 13:00 UTC with Ubuntu Open Week. Luckily I still managed to book a double session, so we’ll have plenty of time to get you started and introduced to Development team and what we do.

The Ubuntu Developer Summit (UDS) will be happening form 29th October to 1st November in Copenhagen and we will have some workshops there as well. If you’re in town, make sure you drop by. Watch the Packaging Guide User Testing and the Get Started with Ubuntu Development workshops. For us it will be great to see how people use the Packaging Guide and what we need to fix. For you it will be great to have people around who are going to help you if you should get stuck. Also it will be a great time to catch up and get to know each other. Thanks a lot to Benjamin Drung (and others) who are going to help with these events.

There will be plenty more activity at UDS which I’ll blog about soon too.