Handling transitions with smooth updates

Lately, I have been working more on release stuff. It all started when Julien convinced me to do the gpsd transition. It was a small, simple transition though I had to bounce obdgpslogger from testing (#648495). After that I picked up the zita-convovler transition (finished yesterday) and gssdp/gupnp{,-igd} (currently blocked by #653131 and #652783). I also got the mono, libindicator+libdbusmenu+libindicate and the libarchive transitions on my to-do list.

The mono transition is going to be most interesting and challenging of these. It is a bit above 100 packages and the binNMU order (for the 30ish packages that are not arch:all) is non-trivial. Thankfully, Iain Laney appears to have that part covered and will be helping me get it right.

I am also very happy with Britney2’s transition assistance. Unlike her retired older sister, Britney2 “smooth updates” libraries, which allows us to break the transition into smaller steps.

Normally when Britney2 migrates a source package, she will throw out all the binaries from the old (version of the) source package. Then she moves the new source package and its binaries into testing. But in a smooth update, she will keep the old library binary packages around (if they are still in use).

In a concrete example, during the zita-convolver transition, we transitioned from libzita-convolver2 to libzita-convolver3. On the 24th of December[1], Britney migrated zita-convolver 3.1.0-1 to testing with libzita-convolver3, but kept libzita-convolver2 in testing as well. This is because ir.lv2 was not ready to migrate at that time.

With Britney1 zita-convolver 3.1.0-1 would have had to wait until all of its reverse dependencies were ready to migrate. For a small transition like zita-convolver (with 3 or so reverse dependencies), it would have been easy. But having to “keep” 100+ packages “migration ready” for the mono transition… that is where handling a transition becomes an art.

I may still need some hinting to finish the mono transition, but most likely it will be a lot easier than it would have been with Britney1. 🙂

[1] The PTS says the 25th. This is because it uses the day it receives the “migration”-email from trille, which was sent the day after.