My grandaughter slept over last night. She’s an early riser. She and I had breakfast at 6am. My wife got a new cell phone (TREO680) yesterday, and I helped her set it up. So I didn’t go to bed until late. In short, I didn’t get a lot of sleep.

A bunch of us are working on a new training example for object oriented design principles and patterns. It’s a large-ish web-based system that has lots of interesting lessons to learn. We’ll be presenting it as a series of exercises throughout the course. Anyway, we’ve all been working as a team, writing this software. It’s been a lot of fun!

Anyway, about 3pm I started to get really tired. I should have stopped. But I wanted to finish one last story! (You know the feeling.) So I pressed on.

I ran accross a small dependency problem between two of the classes. So I started an elaborate refactoring to resolve the issue. An hour later I had to back out the whole refactoring because it didn’t solve the problem, or even come close! I don’t know what I was thinking. The real solution was much simpler and took just 10 minutes or so to implement. I should have stopped then, but, well, you know…

I needed to leave at 5pm. By 4:30 I was executing my unit tests. There was a problem. It didn’t make sense. You know the kind! I stared at the code for a long time, but my brain was mush. I couldn’t think. The lines of code swam before my eyes, but did not speak to me. I should have stopped then.

But no. Instead, I did something I barely ever do. Something I haven’t done in many months. I set a breakpoint! Egad! I was single-stepping through the code. And then I would do that horrible little dance where you step to a point in a module and realize you’ve gone a step or two too far. The variables don’t make sense. So you start over, and step back to just before where you were. Hideous! I should have stopped! But I kept at it. Over and over, breaking, stepping, breaking, stepping.

Debuggers feed you a torrent of information. Even when you are awake it’s easy to misread them. When tired, you see what you want to see, not what you really see. And nothing I saw made any sense. I finally got to the point where an if statement comparing two identical strings was failing! (Or so I thought.) I demanded that the stupid machine was lying. I rebuilt the application. I rebooted my machine. I redid the breakpoint, over and over. No change.

Now it was after 5pm. I really needed to go. I also really needed to fix this damned problem and check in the code. So I did the only thing that might make a bit of sense (other than stopping, which is what I should have done 2 hours before), I turned off the debugger and asked my pair-partner James for some help.

James had been busy helping one of the other guys get subversion working with Eclipse, so he’d been somewhat distracted while I was spinning myself into a debug rathole. He came right over and looked at my unit test. He said “Oh, shouldn’t that fravitz be a dorvitz?”

...

Duh. Yes, that fravitz should have been a dorvitz. It was obvious. It was simple. It was a 2 second change, and the tests all passed. (sigh).

So I, once again, reinforce my rule about debuggers. They are a horrible time-sink. When you find you must debug, it’s time to get help or go home.