Clean Code in Python

Dealing with side-effects in decorators

In this section, we will learn that it is advisable to avoid side-effects in the body of the decorator. There are cases where this might be acceptable, but the bottom line is that, if in case of doubt, decide against it, for the reasons that are explained ahead. Everything that the decorator needs to do aside from the function that it's decorating should be placed in the innermost function definition, or there will be problems when it comes to importing.

Nonetheless, sometimes these side-effects are required (or even desired) to run at import time, and the obverse applies.

We will see examples of both, and where each one applies. If in doubt, err on the side of caution, and delay all side-effects until ...