Was Self-Admitted Technical Debt Removal a Real Removal? An In-Depth Perspective

Technical Debt (TD) has been defined as "code being not quite right yet", and its presence is often self-admitted by developers through comments. The purpose of such comments is to keep track of TD and appropriately address it when possible. Building on a previous quantitative investigation by Maldonado et al. on the removal of self-admitted technical debt (SATD), in this paper we perform an in-depth quantitative and qualitative study of how SATD is addressed in five Java open source projects. On the one hand, we look at whether SATD is "accidentally" removed, and the extent to which the SATD removal is being documented. We found that that (i) between 20% and 50% of SATD comments are accidentally removed while entire classes or methods are dropped, (ii) 8% of the SATD removal is acknowledged in commit messages, and (iii) while most of the changes addressing SATD require complex source code changes, very often SATD is addressed by specific changes to method calls or conditionals. Our results can be used to better plan TD management or learn patterns for addressing certain kinds of TD and provide recommendations to developers.