Heisenbug
ELI5 — The Vibe Check
A bug that disappears when you try to find it. Named after Heisenberg's uncertainty principle — the act of observing (debugging) changes the behavior. Add a console.log? Bug gone. Remove it? Bug's back. Maddening.
Real Talk
A Heisenbug is a software bug that seems to disappear or change behavior when one attempts to study it. This often occurs with race conditions, timing-dependent bugs, or issues affected by debugging overhead.
When You'll Hear This
"It's a Heisenbug — works fine in debug mode but crashes in production." / "Adding logging made the Heisenbug disappear."
Related Terms
Bug
A bug is anything in your code that makes it behave wrong.
Debug
Debugging is the process of finding and fixing the gremlins in your code. Something is broken, and you need to play detective — adding clues (console.
Race Condition
A race condition is when two parts of your code are racing to do something at the same time and the winner isn't guaranteed — leading to unexpected, hard-t...