The Craft of Debugging

Debugging is often treated as a chore—something to get through so we can return to the "real" work of building. But debugging is building. It's the process of understanding systems deeply enough to know where they fail.

The Mindset

Good debuggers share a particular mindset. They're curious rather than frustrated. They treat bugs as puzzles, not obstacles. They know that the system is always telling the truth—even when that truth is unexpected.

The first step in debugging is always the same: reproduce the problem. Not approximately, but exactly. This often reveals that the problem isn't what we thought it was.

Forming Hypotheses

Once we can reproduce, we form hypotheses. What could cause this behavior? Where might the assumption break? What haven't we considered?

The best debuggers form multiple hypotheses and design experiments to distinguish between them. Each observation narrows the space of possibilities.

The Rubber Duck

Sometimes the most powerful debugging tool is explanation. When we explain a problem to someone else—or to a rubber duck—we're forced to articulate our assumptions. Often, the bug reveals itself in the explaining.

Prevention

The ultimate debugging skill is prevention. Code that's easy to debug is code with clear state, explicit error handling, and observable behavior. Every hour spent making code debuggable saves ten hours of debugging.

Debugging isn't a tax on development. It's the practice of understanding. And understanding is the foundation of craft.