Those who pair program with me know that I’m an advocate of leaving comments like // FIXME: Breaks layout on tablets or # TODO: Extract to model. Little reminders of things I don’t want to forget before, say, pushing a new feature.

I have a non-trivial amount of tooling I use around these task-oriented comments, and I’ve been meaning to write about how I use them. Here you go.

My Approach

Often while working on new features (and sometimes, bugs) I sketch out a plan of what I need to do in English with a collection of comments. This helps me break the task into little pieces so I can make sure I don’t miss anything. It also has the benefit of helping me discuss the general approach with my pair so they can consider better solutions.

Next, I distribute these comments to the places where I’m going to code the implementation (if possible); that way they give the reader context so it’s easier to think about the pieces involved. I’ll write the implementation and tests, adding comments as I think of them. I want to write these intermittent notes down quickly so I can forget about them until I’m ready to address them.

Lastly, I like to write myself notes before taking long breaks or quitting for the day. Comments like # TODO: Finish injecting response into view help me to pick up right where I left off later. No more awkward “Now what was I doing yesterday?” moments.

Properties of good TODO comments

This is not so hard, you just have to always write them as if someone else will read them. Remember to make it specific. If it’s a bug, you might explain why, especially if someone else is going to be fixing it. Perhaps you might briefly explain why something should be implemented a certain way. Finally, don’t go overboard! If you can write the code in 30 seconds, why waste time telling yourself what to do.

Improving task-oriented comments with tools

You might be saying to yourself: “But the advantage of a real TODO list is that it’s in one place”. (OK maybe not, but go with me here, eh?) — and you’d be right. That’s where our tools come in; the simplest of which is grep.

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egrep -R "(TODO|FIXME)" *

Editors like IntelliJ IDEA/RubyMine keep track of comments with keywords like this automatically. Just hit ⌘6 (Alt-6 on Windows/Linux) and the aptly named TODO pane comes up. I actually like to add new patterns in IntelliJ’s TODO settings panel, to make FIXME comments stand out in red. Sublime Text seems to have a handy plugin called SublimeTODO that aggregates these keyword comments, as well. Leave a comment with other neat TODO-tracking tools.

We can also utilize git hooks to tell us anything we missed so that we can either fix them before we push or add stories to our favorite agile task board. Here’s the git hook that I use pre-commit:

All this does is print out any new TODO or FIXME comments. To use this git hook, just copy it to .git/hooks/pre-commit in any repo (don’t forget to make it executable). It runs before every commit and you can prevent the commit by returning a non-zero exit code. You can fork the gist here for your own needs.

Finally, Jenkins has a plugin called Task Scanner that lets you track comments matching certain patterns and give them priorities. I like to mark FIXME comments as high-priority and TODO comments as medium or low priority. It’ll also provide reports and charts so you can keep track of your task-oriented comments on a higher level.

Sometimes I don’t use this system if the task is small or I have a really good grasp of how to write the thing I want to write. The point is to program deliberately. Cheers.

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