For those who are interested in the world of compiz, new development snapshots have been trickling their way into experimental for the past week and are now available for widespread testing.

They're being sent to experimental instead of straight to unstable for a few reasons:

• None of us really know how stable / problematic they will be, whether they will build on all arches, or have other RC bugs. So this lets us evaluate the situation and not commit ourselves if we think it's still premature to support them.
• Updating these packages is a major pain and very time consuming, due to how the authors choose to maintain/organize their software. This is really a rant for another day though. Short version is that packages have to be dealt with manually and in a serial manner, and this means they don't all arrive ready to go in one evening's worth of work.
• Since 0.8.x, the upstream authors have moved the locations of some of the repositories, and in some cases rebuilt the repositories from scratch in the process. That meant I had to spend lots of time learning about how to do a few arcane things in git.
• Some of the new packages are using git submodules, which by itself isn't necessarily bad. However, for maintaining debian packages out of git with submodules, this a fairly exotic concept and requires some changes to the typical packaging workflows as well as maybe needing to hack some support into commonly used packaging tools.

So, anyway, the packages are all uploaded now--give them a try!

...For the cases where, yes, you actually do want it.

For the impatient

assuming you're in a clean checkout on the tip of your current branch:

git merge -s ours ref-to-be-merged
git diff --binary ref-to-be-merged | git apply -R --index
git commit -F .git/COMMIT_EDITMSG --amend

you can then double check that everything is as you expect with git diff ref-to-be-merged, which should be empty.

The longer story

It's noted from time to time that git does not have a -s theirs option to complement the -s ours strategy when merging (or, it did, but it was removed long ago, see below). For those not savvy the idea with git merge -s ours is to pretend as though a merge from some other branch has occurred, though the result remains the current branch's contents, unchanged. This is a neat trick that can be used to show that all changes in some branch have been superceded by the current branch, which can help ease merges further down the line as parallel devlopment continues.

However, there is no corresponding -s theirs option, which would conversely say that "everything developed up to here is superceded by this other branch". This feature was discussed and discarded by one of the git authors, who instead advised a developer to throw away the previous work and start on a fresh branch:

One big problem "-s theirs" has, compared to the above "reset to origin, discarding or setting aside the failed history" is that your 'master' history that your further development is based on will keep your failed crap in it forever if you did "-s theirs". Hopefully you will become a better programmer over time, and you may eventually have something worth sharing with the world near the tip of your master branch. When that happens, however, you cannot offer your master branch to be pulled by the upstream, as the wider world will not be interested in your earlier mistakes at all.

In what would probably qualify as "most cases", he's right, but sometimes you do want to do this, and not because you have "crap" in your history, but perhaps because you want to change the baseline for development in a public repository where rebasing should be avoided.

In debian, for example, it's pretty common for maintainers who use git-buildpackage to build debian packages from git to have two branches: an "upstream" branch and a "debianized" branch. The upstream branch will follow the changes from the upstream project (either by importing tarballs, or by pulling directly from the project's git repo if they also use git), while the debianized branch contains all the packaging related changes as well as any debian-specific changes to the code.

In this context, if the upstream project uses git and rebases their history (out of your control), or if they shift development to a different branch, you might want to have a way to merge with their latest changes without rebasing/abandoning your current debian branch. Hence, a "theirs" merge.

The author is totally right that the upstream project may be less interested in pulling from such a repository (since they would drag in the entire previous history), and if that's a problem you might need to splinter off the old branch and start a fresh branch instead. But at least for the projects with which I work, I find that it's more likely that pulling is pretty much one way upstream to debian, and that the patches flow back to the upstream project by way of bug trackers, git format-patch | sendmail, or quilt patches sitting in the patch-tracker. And if it becomes a problem later you're no worse off, you can still split off a new branch or take some other action.

So anyway, I asked Teh Internetz and found a few hits in the right direction, such as this guy at stack overflow, or this guy here. But from an aesthetic point of view I thought their solutions still left some room for improvement--they were both more complicated, involved setting up temporary branches, and I don't know, just weren't pretty on the eyes. So, ending where I started, this is the relatively clean and easy to follow 3 lines I conjured up, which I will give to teh internetz for posterity.

git merge -s ours ref-to-be-merged
git diff --binary ref-to-be-merged | git apply -R --index
git commit -F .git/COMMIT_EDITMSG --amend

Alternatively, if you want to keep the local upstream branches fast-forwardable, a potential compromise is to work with the understanding that for sid/unstable, the upstream branch can from time to time be reset/rebased (based on events that are ultimately out of your control on the upstream project's side). This isn't a big deal and working with that assumption means that it's easy to keep the local upstream branch in a state where it only takes fast-forward updates. However, on the debian branch your less interested in the clean upstream development, and instead want to keep a sane history of the debianization work, so on this branch you still do something like a merge -s theirs (though in this case, you probably want to amend the previous version's ./debian dir back in post-merge). So applying the same approach as above with the slight modification, in practice (assuming you're on the clean tip of the debian unstable branch, that'd be):

git branch -m upstream-unstable upstream-unstable-save
git branch upstream-unstable upstream-remote/master
git merge -s ours upstream-unstable
git diff --binary ref-to-be-merged | git apply -R --index --exclude="debian/*"
git commit -F .git/COMMIT_EDITMSG --amend

PS

In spirit, this is a similar approach to what's done by the XSF team, though I would argue that with what I'm describing both the approach and the resulting history are a bit cleaner and easier to follow.

Also, thanks to ron, mrvn, jcristau, and nthykier on #debian-devel for some quick reviewing of this.

PPS

From further usage, I discovered if you have non-text files involved you'll need a --binary thrown into the above example, so I've updated them accordingly.

I also got a bit more feedback that I'd like to share, just for the sake of being complete and showing some alternatives (TMTOWTDI).

Barak A. Pearlmutter shared his version, which from a quick read would also do the trick:

When I want "git merge -s theirs HERS" onto MINE, I do this:

git checkout MINE
git merge --no-commit -s ours HERS
git rm -rf .
git checkout HERS -- .
git checkout MINE -- debian # or whatever, as appropriate
git gui # edit commit message & click commit button

Michael Gebetsroither chimed in, claiming i was "cheating" and gave another solution with lower-level plumbing commands:

(it wouldn't be git if it wouldn't be possible with git only commands, everything in git with diff/patch/apply isn't a real solution ;).

e.g

# get the contents of another branch
git read-tree -u --reset <ID>
# selectivly merge subdirectories
# e.g superseed upstream source with that from another branch
git merge -s ours --no-commit other_upstream
git read-tree --reset -u other_upstream     # or use --prefix=foo/
git checkout HEAD -- debian/
git checkout HEAD -- .gitignore
git commit -m 'superseed upstream source' -a

Thanks for the feedback!

Packaging updates

• dbconfig-common: New translations, features, and a particularly nasty bug fixed.
• cacti: Some packaging fixes, and a few upstream patches cherry-picked into the next version. Also uploaded the new upstream version of cacti-spine.
• xmlrpc-c: New upstream version, including a long postponed library transition.

Help wanted: cacti

I've also filed an RFA bug for cacti (and spine), as i'm not really using cacti any more in my day to day work. The packages are in pretty good shape, but it would really be for the best if someone who actually used cacti were able to more thoroughly test new versions before they were uploaded. I'm also open to co-maintaining the package and/or sponsoring uploads; so if you're already using cacti and looking to get involved in debian development, this could be a fun place to start

Debian patch tracker

Finally got around to fixing a couple post-release (and older) issues in the patch-tracker. Hopefully it should be back to updating and following the latest stuff in the archive.

Next up I'll see if I can find someone from DSA to upgrade the hosting machine to squeeze and install a few extra dependencies for the next feature update, which contains a pretty substantial rewrite of the guts from some home-rolled wsgi+cheetah goo to a more established and maintainable django-based system.

In the meantime, please let me know if you see any problems (via maintenance cat or otherwise), and I will take a look.

update: 20100503: It's been brought to my attention that there might have been a regression in one of the libraries, mesa, maybe, so that master might not be as reliable a reference point for this guide. so, just in case, here are the commit hashes that were used from the different projects:

• dri2proto: c34ce137fdb21fc9a52bb8d5a0c25e3c5d79e687
• drm: 6293152eb065016a2e5e4fcd047c2db5c2fb0f36
• linux-2.6 (nouveau master) f108a544dbc9b64b0b42cfc6e21bc4f5ffd38998
• mesa: dd3b98bdf67df9a5b1127bf7d50bbb6691597bfb
• xf86-video-nouveau: 13c10430ba8f7b0edff3ad8aae4a97672eea4a8f

for the non-git-savvy: git checkout -b mybranch <hash>

we now return to your regular broadcasting...

A week or two ago I figured it was about time that I took the plung and tried out the latest nouveau drivers from experimental on my laptop. Unfortunately, it meant bidding adieu to compiz (apart from the bling it does actually provide some pretty damned useful features). I thought I'd give it a shot at least for a while on principal, since I've always had to think of the nvidia drivers as a necessary evil, and their lack of proper xrandr support is really, really annoying.

Since then I haven't noticed any problems, apart from the following message after every suspend/resume:

[  931.213239] Uhhuh. NMI received for unknown reason 80 on CPU 0.
[  931.213240] You have some hardware problem, likely on the PCI bus.
[  931.213242] Dazed and confused, but trying to continue

No idea what's causing it, but otherwise the system is stable and functional. If anyone knows what can be done about this, I'd appreciate hearing from you.

My graphics card, by the way:

01:00.0 VGA compatible controller: nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300] (rev a1)

In the time since then, the nouveau driver has made its way into unstable, and a lot of distros (ubuntu, fedora, ...) are even using it as the default driver. So before going any further with the 3d/compiz stuff, I highly recommend that you get the packaged version working first. This will not only make sure that the basic driver works, but it will also make recovery/rollback a lot easier. Since it's all packaged in the standard repositories, it's not much harder than installing a few packages and editing a few files... so come on give it a try

Getting the 2d driver working in Debian sid

Really, this is so easy it's hardly worth writing up, but i'm running with the -v flag this morning...

Make sure you don't have any reference to nvidia in /etc/modules or other places that might cause it to be automatically loaded. Then remove the proprietary glx bindings, which would otherwise interfere with the nouveau driver.

sudo apt-get remove nvidia-glx

Next, you'll need to install a kernel that includes updated drm support. Normally this would require a kernel >= 2.6.33.1, but the debian kernel maintainers have graciously backported this code to the 2.6.32-4 kernel package. note this isn't the default kernel version in testing/unstable at the time of writing so you have to explicitly install it along with the nouveau driver.

sudo apt-get install linux-image-2.6.32-4-amd64 xserver-xorg-video-nouveau

If you are already running this kernel and using the proprietary nvidia drivers, via module-assistant or otherwise, you /might/ need to uninstall them first. On my system I left them installed in the old kernel version but did not install them on the new kernel version.

Required xorg configuration

I don't believe that nouveau is picked by default if available at the time of writing, so you have to have the following in your xorg.conf:

sudo sh -c "cat > /etc/X11/xorg.conf" << EOF
Section "Device"
    Identifier     "nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300]"
    Driver         "nouveau"
EndSection
EOF

This was all I needed to do, apart from rebooting into the new kernel. For those who don't want to venture outside the packaging system, this is about as far as you can go for the time being. Though really, if you're bothering to read this far along, you're probably more interested in what comes next

Getting 3d working (without voiding your distro warranty)

So I thought I'd give the 3d-accelerated gallium a go. Their wiki page certainly makes one think twice, but at this point I was seriously fiending to get my bling back (well, the compiz scale plugin, anyway) and figured it wouldn't hurt too much to try.

Via google and trawling around in various forums I found a number of how-to documents for getting Gallium3d on debian/ubuntu systems, but most of them recommended doing things in a way that wasn't easily reversible and that could totally hose your system in a not-so-hypothetical worst-case scenario. It's pretty hard to roll back a make install done into /usr, for example, and subsequent package upgrades can leave your system even worse off as they will probably clobber half of what you just did, leaving the other half totally broken. And if you have a laptop which requires the gui for networking (i.e. network-manager), then fixing/rolling-back the changes is not entirely trivial, since you'd likely have to re-download the various drm/mesa/xorg packages.

So enter the tried and true unix utility stow (apt-get install stow, of course). stow is a utility that lets you install software into arbitrary folders, and then manage the system-wide installation of the software via a farm of symlinks pointing at the installed location. It's probably more well known among the sysadmin crowd than the desktop user crowd, but it's incredibly useful for the task at hand as it will let us easily install multiple copies of different software in a way that's very easy to update and/or roll-back. RTFM stow(1) for more information.

So, on to the juicy stuff...

Install needed software, remove problematic packages, setup, etc

At least on my system, I had to remove libdrm-dev to keep things from accidentally linking against it instead of the updated version that we install later on below. There's probably a way to override this with CFLAGS but I figure this is simpler.

sudo apt-get remove libdrm-dev
sudo apt-get install stow build-essential xorg-dev git-core libtool mesa-common-dev automake autoconf 
mkdir ~/nouveau

Compile a linux-2.6.34 RC kernel

cd ~/nouveau
git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
cd linux-2.6
git remote add -f nouveau git://anongit.freedesktop.org/nouveau/linux-2.6
git checkout -b nouveau-master nouveau/master
make menuconfig

Enable device drivers -> staging drivers -> nouveau. Make any other changes you might want to make (I just took defaults for everything else).

make deb-pkg

The linux-firmware-free debian package ships some of the same stuff from the generated linux-firmware-image package. I decided to opt for the upstream firmware, though I'm not sure that this is necessary:

sudo apt-get remove linux-firmware-free
sudo dpkg -i ~/nouveau/linux-image*.deb ~/nouveau/linux-firmware-image*.deb
sudo update-grub

Install a copy of dri2proto

cd ~/nouveau
git clone git://anongit.freedesktop.org/xorg/proto/dri2proto
cd dri2proto
./autogen.sh --prefix=/usr/local/stow/dri2proto-20100428
sudo mkdir -p /usr/local/stow/dri2proto-20100428
sudo make install
sudo stow -d /usr/local/stow dri2proto-20100428

Install a cutting-edge version of libdrm

cd ~/nouveau
git clone git://anongit.freedesktop.org/git/mesa/drm/
cd drm
./autogen.sh --prefix=/usr/local/stow/drm-20100428 --disable-intel --disable-radeon --enable-nouveau-experimental-api
make
sudo mkdir -p /usr/local/stow/drm-20100428
sudo make install
sudo stow  -d /usr/local/stow  drm-20100428

Likewise for mesa

cd ~/nouveau
git clone git://anongit.freedesktop.org/git/mesa/mesa
cd mesa
./autogen.sh --prefix=/usr/local/stow/mesa-20100428  --enable-debug --enable-glx-tls --disable-asm --with-dri-drivers= --enable-gallium-nouveau --disable-gallium-intel --disable-gallium-radeon --disable-gallium-svga --with-state-trackers=glx,dri --with-demos=xdemos,demos,trivial,tests
make
sudo mkdir -p /usr/local/stow/mesa-20100428 
sudo make install
sudo stow -d /usr/local/stow mesa-20100428

And now the xorg driver...

cd ~/nouveau
git clone git://anongit.freedesktop.org/git/nouveau/xf86-video-nouveau/
cd xf86-video-nouveau
./autogen.sh --prefix=/usr/local/stow/xf86-video-nouveau-20100428
make
sudo mkdir -p /usr/local/stow/xf86-video-nouveau-20100428
sudo make install
sudo stow -d /usr/local/stow xf86-video-nouveau-20100428

Configuration

Configure xorg to look in alternate location for xorg modules and set up DRI

sudo sh -c "cat > /etc/X11/xorg.conf" << EOF

Section "Files"
    ModulePath "/usr/local/lib/xorg/modules,/usr/lib/xorg/modules"
EndSection

Section "ServerFlags"
    Option "GlxVisuals" "all"
Endsection

Section "Device"
    Identifier     "nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300]"
    Driver         "nouveau"
EndSection

EOF

I've /heard/ that disabling TV out is a necessity on some cards, though I haven't seen this myself:

sudo sh -c "cat > /etc/modprobe.d/nouveau.conf" << EOF
# not entirely sure this is necessary, but heard it helped with vsync
options nouveau tv_disable=1
EOF

Finally, the one thing that can not be done in /usr/local is making the nouveau DRI driver available. From what I could tell the path that mesa uses to find the DRI libraries is hard-coded (corrections welcome). Since you won't already have this file (otherwise, why would you be following along here?), just drop in a symlink to the file in /usr/local:

sudo ln -s /usr/local/lib/dri/nouveau_dri.so /usr/lib/dri/

Finally, reboot, and hope for the best

Riding the bleeding edge: how to upgrade later on

Again, stow really shows its usefullness here. Using drm as an example case, upgrading an individual component would look something like:

cd ~/nouveau/drm
git clean -dfx
git pull
today=`date +%Y%m%d`
./autogen.sh --prefix=/usr/local/stow/drm-$today --disable-intel --disable-radeon --enable-nouveau-experimental-api
make
sudo mkdir -p /usr/local/stow/drm-$today
sudo make install
sudo stow -d /usr/local/stow -D drm-20100428
sudo stow -d /usr/local/stow  drm-$today

Note how the old version is still installed, so you can switch components around pretty freely.

Abort! Abort!: How to roll back changes

In case your system becomes totally unusable, or you've decided that you just want to go back to the safe and cozy world of what's provided by the debian packages, simply do the following:

• Remove the ModulePath directive from your xorg.conf
• Remove the nouveau_dri.so symlink from /usr/lib/dri
• Possibly(?) boot into your previous kernel (I read grumblings about ABI breakage on lkml which might mean that you can't use the same libdrm with the old/new drivers, though I haven't had to find out).

Assuming that you're using the nouveau driver from unstable, this should be all that is necessary.

Conclusion

Overall impression

I am very, very happy with the resulting setup. I was led to believe that this whole thing was much more unstable and unusable than it actually is! While there are certainly some glitches and missing features, I feel comfortable enough using it that I don't have plans to switch back. But if I find myself in a situation where I can't use the new setup, rolling back shouldn't be a problem either. I figure I'm happy with what I have now and it will only get better.

What works, at least to a "kinda works" level.

• A standard compiz installation
• Basic 3d support
• Xvideo
• Display port switching with fn-F7 (but see below)
• Suspend/Resume (most of the time, anyway)

What still doesn't work

• Suspend/Resume doesn't /always/ work, I wouldn't call it 100% reliable anyway
• I've had an occasional graphical lockup of the system requiring reboot
• Switching display ports only partially works (one of the two displays will usually be corrupted, though the other will work ok).
• Docking and undocking combined with suspend/resume and switching displays seems to trigger some hard lockups.
• Haven't tried extensive use of 3d-apps yet.
• Graphics glitches/artifacts
• A number of things will make compiz crash. When this happens it automatically falls back to metacity, so it's not a huge problem--just pretty annoying.
  • gnome-display-properties
  • using the compiz "Resize Window" plugin with "Normal" (change it to "Rectangle")
  • switching from lcd to external monitor will sometimes cause it to crash
  • I would guess other plugins might be problematic as well, though at least what I had enabled previously seems to work okay.
• Any kind of GPU power saving features (graphics card runs pretty hot, anyway).

Further reading, references

• DRM installation guide
• Kernel modesetting tips
• Gallium3D howto
• Tips for lockup recovery
• An earlier ubuntu how-to

Thanks

A couple shoutouts to those who helped me with this on the way:

• all the developers involved in the respective projects... a big Thank You!
• ymanton, mwk, calim, paerley on #nouveau for helping me troubleshoot kernel/libdrm issues.
• KiBi on #debian-x for all the work getting nouveau into unstable.

Feedback / Corrections

Unforunately, I've had to disable comments for the time being due to overwhelming quantities of spam. So please drop me a line via email or on IRC (seanius on oftc/freenode).

this computer is in use and can not be unlocked

this weekend while giving a bit of TLC to the php packages, i thought i'd finally get around to tackling #490023 and similar bugs, which meant learning about how to use the triggers feature provided by dpkg.

unfortunately documentation for this feature was in fairly short supply, and after extensive searching (and by extensive searching i mean typing "dpkg triggers howto" into a google search) i had a couple short manpages (dpkg-trigger(1) and deb-triggers(5)) and an overly verbose and possibly out of date /usr/share/doc/dpkg/triggers.txt.gz. none of these documents really gave a clear "big-picture" for how to get going either.

so, as is often the case, i got distracted from my intended task and ended up on a little side-project putting together a nice howto/tutorial for how to integrate dpkg triggers into a package. note that there may be misunderstandings or inaccuracies in the document, as it's based on an afternoon's worth of hacking and q&a directed at #debian-dpkg (thanks to Guillem and Raphaël for fielding those questions). so if i'm off on anything, please feel free to let me know!

to get started:

git clone http://git.debian.org/git/users/seanius/dpkg-triggers-example.git

and for those who are too lazy even for that, the README follows:

The debian package triggertest

This package is a dead-simple "triggers in a nutshell". It shows a few different ways that triggers can be used in practice, to hopefully cover most of the general use cases for triggers.

The purpose of triggers

Triggers are used to ensure that during the standard package-management process certain operations always run, but not more than necessary. For example:

• during an upgrade many packages might provide updated texinfo(5) documentation, and triggers are used to ensure that update-info-dir(8) is run without having to be run several unnecessary times from the maintainer scripts of package in question.

• if a system has both apache2 and PHP's apache2 engine installed, apache2 will need to be restarted whenever new php extensions are installed or removed. Without triggers it would be very disruptive (and inefficient) to explicitly stop and start apache by each PHP extension.

• update-initramfs(8) should be run once and only once after kernels are updated or certain other packages are installed/upgraded that would want to have a new initramfs generated.

• other expensive operations that are desirable to be aggregated and consolidated during installs/upgrades, such as update-texmf(8) or scrollkeeper-update.

How triggers work in a nutshell

Trigger-using packages can be classified in two behavioral categories:

• Consumers: packages which declare triggers and thus can be "triggered"
• Producers: packages which activate triggers (explicitly or implicitly)

When a consumer is triggered, its postinst script is run with the arguments:

postinst triggered "<trigger1> ... <triggerN>"

i.e. $2 contains an iterable list of activated triggers.

Note that if a consumer is going to be normally configured (i.e. it is also being updated), then no triggering may occur and thus the standard control flow of the maintainer scripts should still take care to handle this.

A "trigger" is declared for the consumer by shipping a file in DEBIAN/triggers (in the case of debhelper based packages, ./debian/consumer-package.triggers will JDTRT). Useful RTFM: deb-triggers(5).

Example:

interest /path/to/a/directory
interest my-second-trigger

This declares that the package in question is interested in two triggers.

The first trigger has a leading path separator in its name, which instructs dpkg that any filesystem modifications underneath this directory by other packages should cause the respective consumer(s) to be triggered.

The second name is completely arbitrary (and also global, so you should probably pick something reasonably specific and identifiable), and will only cause a trigger to be activated when a producer

1. ships its own triggers file with a corresponding "activate my-second-trigger", or
2. invokes the trigger explicitly in a maintainer script by calling "dpkg-trigger my-second-trigger".

Another perhaps useful RTFM: dpkg-trigger(1).

Examples contained in this source package

This source package produces a single "consumer" package and a number of different "producer" packages. The consumer is triggered in various ways, such as:

• Filesystem updates to a given directory from any other package
• "activate foo" from a producer's triggers file
• Activation from a producer's explicit call to dpkg-triggers

In this case the triggers correspond to an "update-foo" and "update-bar" command, which do nothing other than echo to the console that they are being run. In practice they'd correspond to updating some kind of database or restarting a daemon.

More information

For more information about triggers, see /usr/share/doc/dpkg/triggers.txt.gz, which will make a lot more sense having a working example like this package as reference. Especially useful is "Transition hints for existing packages", which can be used if you need to gracefully handle migrating in support for triggers across other packages not directly under your control.

Corrections, suggestions, etc

Are appreciated and should be sent to the author, below.

-- Sean Finney seanius@debian.org Sat, 19 Sep 2009 15:57:48 +0200

thanks largely to Peter Palfrader and Bernd Zeimetz, the debian patch-tracker is back alive and now hosted as an official debian.org service: http://patch-tracker.debian.org.

in addition to the new host, i've made a few very basic optimizations that will hopefully reduce the strain when someone browses through some of the larger patch sets (ehem, openoffice.org, i'm looking at you).

if you notice any problems with the service, please drop me a line.

continuing on the trend of finding novel ways to make life more interesting with git, here's the description from a new hook:

# prepare-commit-msg hook for debian package git repositories
#
# this script scans the diff that is going into a commit, and automatically
# injects some "proposed" comments based on what it finds in the diff.  this
# can be used to avoid a few extra keystrokes when performing some of the
# more standard/boring tasks.

(see below for how to fetch the script)

this one definitely falls in the "carrot" category, as it encourages properly isolated (and thus automatically identifiable) changes. the proposed comments are then given to the standard editor, so one can easily amend them, append "Closes:" lines, etc.

some sample use-cases currently implemented:

• changelog entries

  • detect when a new version is introduced in debian/changelog

    prepare release information for <dist>/<vers>
    

  • detect when an existing version is updated in debian/changelog

    release information for <dist>/<vers>
    

• debconf translations

  • detect when one or more po files are modified

    updates to (<lang1>,<lang2>...) debconf translations
    
    
     * <lang1>: <translator for lang1>
     * <lang2>: <translator for lang1>
    

• updates in debian/patches

  • detect when a new patch is introduced

    new debian patch <patchname>
    
    
    <patch header (anything before the diff)>
    

  • detect when an existing patch is modified

    update debian patch <patchname>
    
    
    <patch header>
    

  • detect when several patches are imported simultaneously

    import <n> files in debian/patches
    
    
    <patch1>:
      <patch header>
    <patch2>:
      <patch header>
    <non-patch-file (series/etc)>:
      no patch description/comments found
    ...
    

  • detect when several patches are created/modified simultaneously

    create/update <n> files in debian/patches
    ...
    

as always, comments/feedback/suggestions/etc welcome

using this new hook

note this is the same repo as the previous hooks i've blogged about, so if you already have that set up you can skip the clone and instead just pull in the changes. also note that this is in your local repo, not the remote one.

to set it up:

REPO_PATH=/path/to/your/repo.git
HOOK_REPO_PATH=/somewhere/you/want/to/put/it
git clone git://git.debian.org/users/seanius/vcs-hooks/git-hooks.git $HOOK_REPO_PATH
ln -sf $HOOK_REPO_PATH/debian/git-hooks/prepare-commit-msg-guess-message.py $REPO_PATH/.git/hooks/prepare-commit-msg

there aren't currently any configurable options in this hook.

previously i threw together a small hook to make it a bit easier to avoid duplicate work while maintaining packages, as well as easily keep the BTS up to date with relevant information.

now i've commonized the code just a bit and have a second hook which can be used to maintain certian (what i believe to be) good practices for keeping packages in git. admittedly, it's a bit more "stick" than "carrot" with respect to streamlining workflows, but i feel the justifications and the resulting benefits are worth it.

so the hook does basically two things, either of which can be customized and/or disabled.

prevent "non-debian" changes on a "debian" branch

assuming that there are seperate branches for "debian" packaging and for "upstream" development, this hook prevents upstream-style changes on the debian branches. that is to say changes to files outside ./debian are not permitted on a "debian" branch, unless of course you're merging from an upstream branch.

instead, changes to the source in a debian branch should be managed by quilt-style "feature patches", or a more advanced branch topology using some kind of feature branches (topgit or similar).

prevent changelog modifications from being mixed in with other commits

this one might be a bit more controversial for some. basically, the idea is that:

• stuff is fixed in a commit
• there is a log message for this commit, which contains a description of the fix
• the changelog update is redundant information to this log
• it's impossible to merge/cherry-pick/revert the fix later if the changelog gets tangled into the commit.
• there are nice tools (git dch) for managing debian/changelog updates anyway.

therefore, this hook "declines" commits which modify debian/changelog, unless it is the only file being changed.

using this new hook

note this is the same repo as the other hook, so if you already have that set up you can skip the clone and instead just pull in the changes.

to set it up:

REPO_PATH=/path/to/your/repo.git
HOOK_REPO_PATH=/somewhere/you/want/to/put/it
git clone git://git.debian.org/users/seanius/vcs-hooks/git-hooks.git $HOOK_REPO_PATH
ln -sf $HOOK_REPO_PATH/debian/git-hooks/pre-receive-fileset-fascism.py $REPO_PATH/hooks/pre-receive

the config options for controlling this hook (these are git config options just like the other hook):

# hooks.debianbranches (default: 'debian-.*')
#    a regular expression which indicates which branches are "debian" branches.
#    in the context of this hook such branches are not allowed to have changes
#    in files outside of the ./debian directory.
# hooks.sacredchangelog (default: True)
#    if set to True, debian/changelog can not be changed in a commit that
#    also modifies other files.  this helps ensure changes that are easily
#    merged/cherry-picked/reverted.

examples of the hook in action

rejecting a commit that has an entangled changelog:

rangda[~/debian/php] git push                                  :)
Counting objects: 9, done.
Delta compression using 2 threads.
Compressing objects: 100% (5/5), done.
Writing objects: 100% (5/5), 442 bytes, done.
Total 5 (delta 4), reused 0 (delta 0)
fileset-fascism rejecting commit 2fab3269b3d9daedd7013a576483a11ccb4cb86a
    debian/changelog must be changed seperately from other files.
    changed files in this commit:
        debian/changelog
        debian/control
error: hooks/pre-receive exited with error code 1
To ssh://git.debian.org/git/pkg-php/php.git
 ! [remote rejected] debian-sid -> debian-sid (pre-receive hook declined)
error: failed to push some refs to 'ssh://git.debian.org/git/pkg-php/php.git'

rejecting a commit that has non ./debian changes:

rangda[~/debian/php] git push                                  :)
Counting objects: 5, done.
Delta compression using 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 309 bytes, done.
Total 3 (delta 2), reused 0 (delta 0)
fileset-fascism rejecting commit d96669c0780e33b250af81404e263fc181fe0547
    non ./debian changes on a debian branch in this commit.
error: hooks/pre-receive exited with error code 1
To ssh://git.debian.org/git/pkg-php/php.git
 ! [remote rejected] debian-sid -> debian-sid (pre-receive hook declined)
error: failed to push some refs to 'ssh://git.debian.org/git/pkg-php/php.git'

as always, comments/feedback/suggestions/etc welcome

so i had a couple videos to mention and i figured i'd use the chance to write an ikiwiki template to do so. it's not the most flexible, but it works! current template code, put into templates/youtube.mdwn:

<div class="youtube">
 <object width="445" height="364" 
     data="http://www.youtube-nocookie.com/v/<TMPL_VAR raw_v>&fs=1&border=1" >
  <param name="allowFullScreen" value="true" />
  <param name="allowscriptaccess" value="always" />
  <param name="movie" 
     value="http://www.youtube-nocookie.com/v/<TMPL_VAR raw_v>&fs=1&border=1" />
 </object>
</div>

using it:

[[!template  id=youtube v="sPq3c5D65hE"]]

gets you:

(not sure if that will show up on a syndicated site)

it's also xhtml compliant, unalike the default "share this" text and what's produced by the deprecated embed plugin. it also uses the "no automatic cookies" option provided by youtube. i might try and break out a few more options into parameters the next time i post videos.

on a related note, does anyone know a good way to include/display the code of a template on a page? this stuff here is just cut/pasted but it would be nicer to be able to not have to do that to keep it up to date.