Today, as an experiment, I attempted to fix a Debian bug while on the train to work.

I use a 3G card from in my Lenovo Thinkpad x121e, and my commute is from Southampton Central to Fleet (changing at Winchester) - just under an hour. 3G coverage is not 100%, but tends to be better around the major stops.

  • First, I found a bug. I used to browse for a relatively simple RC bug, and found bug #674992 in actionaz. The fix was outlined in the report already, so there was very little thinking required.
  • Next, I confirmed the FTBFS using cowbuilder. Unfortunately, this required downloading roughly 120MB of dependencies - I have 1GB of data per month, but I couldn't afford to do this every day. I was lucky in that I was near Basingstoke at the time, so had a good HSDPA signal to get the bulk of this. The build had failed before I reached Fleet.
  • In the background, I updated debian/control and debian/changelog with the fix. I was able to set off the build, but had to suspend the laptop until lunchtime before it could finish. Cowbuilder needed to download only a few extra build-deps, as the vast majority were cached from the initial run.
  • On the train home, I checked over the result, signed it and uploaded. In this instance, the built package was small enough to upload, but I could see this being a problem with others.
  • Finally, I sent the nmudiff, although that was delayed briefly by a drop in connectivity before Southampton Airport.

Thoughts: firstly, part of me is amazed that this is possible. Secondly, there could be a case for a local Debian mirror on my laptop. Otherwise, an interesting experimental extension to UDD would be "Required bandwidth" - the sum of the recursive build-dependencies plus the upload size of the diff/binaries.