Since a while, I've been using git-buildpackage to manage the Debian packaging for OpenTTD. This offers the option to sign the tags created by git-buildpackage, which is of course cool. However, I've found that I always need to load my GPG key into my gpg-agent first to make that work. If I didn't, I'd see the following:

You need a passphrase to unlock the secret key for
user: "Matthijs Kooijman <matthijs@stdin.nl>"
1024-bit DSA key, ID 8A2FAFBC, created 2005-05-27

gpg: cancelled by user
gpg: skipped "Matthijs Kooijman <matthijs@stdin.nl>": bad passphrase
gpg: signing failed: bad passphrase
error: gpg failed to sign the tag
error: unable to sign the tag

This also occurs when calling git tag directly, but not when calling gpg --sign.

I've finally done some research to this, and found that this can be solved by setting the GPG_TTY variable in every shell. According to the gpg-agent manual, you should add the following to your ~/.bashrc:

GPG_TTY=$(tty)
export GPG_TTY

And whaddayaknow, it works! Sounded pretty silly to me (why not just use $tty directly?), but it actually makes some sense. First of all, $(tty) is not an evironment variable, but an invocation of the tty command.

Secondly, it seems of course silly to put this in the environment when the passphrase-asking code could just find out the current tty by itself. However, it seems that it is actually gpg-agent itself that initiates the passphrase dialog. When I unset $GPG_AGENT_INFO in my terminal, git tag asks for a passhprase normally (but just with an "Enter passphrase:" prompt, instead of the full-screen curses-based prompt I get normally).

This probably means that whatever code is calling gpg-agent from within git tag, is sending along the value of the GPG_TTY variable (or perhaps simple all of the environment?). I guess the gpg command automatically sets the GPG_TTY variable internally, which is why using gpg directly just worked.

This also explains why, after entering my passphrase, my key was added to the agent as well.

This morning I've entered the next stage of my car mechanic career: I've stopped by the junkyard to get some spare parts for Brenda's car. About a year ago, I broke off one of the door handles from the car (the door was frozen shut, and I underestimated my own strength...). The KIA dealer was happy to replace the handle, for EUR 150 or something silly like that. Considering there was enough of the handle left to operate the door perfectly (after being pointed out which part to hold, mostly), we just left it broken for a year.

A few weeks back, we found a crack in one of the outer mirrors. There was no clue how this happened, but perhaps it got hit by some stray snowball or the winter's cold made it snap. Since the outer mirrors are a failure point for the APK (yearly checkup), we really needed to replace those.

So, this morning I went to a local junkyard, that had an old Kia Pride. It was a ghostly sight, all those half disassembled cars. Some missing wheels, hoods, doors, etc. They had a spare mirror on the shelf, but the door handle was still on the car. I found a blue Kia Pride out back, and after some fiddling disassembled the door handle. I actually quite like this junkyard thing: Not only do you get to do stuff with your own car, you can find out how its done on some other car first, without the risk that you break more stuff while prying something loose.

Just now, Brenda and me put on the "new" parts, so the car is as good as new again (if you ignore the occasional squeeking and creaking, of course), for just EUR 25.

Next up is finally fixing up some rusty spots on the paint of the car, but I'd really like to have some place to put the car inside for a few days for that (lest my fingers freeze off and the new paint won't dry).