Software Architect's Handbook

Commented-out code

Commented-out code is code that is currently not in use and has been commented out by a developer rather than deleted. Code that is commented out is among the easiest types of code to remove. Sometimes a developer may comment out code with the intention of it only being temporary but then does not follow up later to either remove or uncomment the code.

Lines of code are sometimes commented out to serve as a record of previous logic. However, having a change history is one of the purposes of a version control system. Leaving code in the codebase that has been commented out only increases the size of the code and makes it less readable.