Code Smell 15 - Missed Preconditions
If you turn off your assertions just in production your phone will ring at late hours.
15 October, 2022
0
0
0
Contributors
Assertions, Preconditions, Postconditions, and invariants are our allies in avoiding invalid objects. Avoiding them leads to hard-to-find errors.
TD;DR: If you turn off your assertions just in production your phone will ring at late hours.
Problems
•
Consistency
•
Contract breaking
•
Hard to debug
•
Bad cohesion
Solutions
•
Create strong preconditions
•
Raise exceptions
•
Fail Fast
•
Defensive Programming
Examples
•
Constructors are an excellent first line of defense
•
Anemic Objects lack these rules.
Sample Code
Wrong
Right
Detection
•
It's difficult to find missing preconditions, as long with assertions and invariants.
Tags
•
Consistency
Conclusion
Always be explicit on object integrity.
Turn on production assertions.
Even if it brings performance penalties.
Data and object corruption is harder to find.
Fail fast is a blessing.
More info
Relations
Credits
Photo by Jonathan Chng on Unsplash
Writing a class without its contract would be similar to producing an engineering component (electrical circuit, VLSI (Very Large Scale Integration) chip, bridge, engine…) without a spec. No professional engineer would even consider the idea.
Bertrand Meyer
This article is part of the CodeSmell Series.
programming
refactoring
cleancode
codesmell