An empirical study on how project context impacts on code cloning

摘要

Code cloning can seriously affect software quality. Code clones are various fragments of syntactically or semantically equivalent code. Some authors argue that code clones have a negative impact on maintainability and understandability, since clones propagate defects and make it mandatory to pay attention to several copies. However, other authors believe clones are not necessarily bad, since self‐admitted clones favor system stability and allow developers to move projects forward. Although some root causes and effects of cloning have been widely studied, there is not much relevant work analyzing how certain projects context factors impact on code cloning. This work presents an empirical validation of six open source projects by considering certain factors from Git repositories measured throughout a total of 70 releases for the 6 systems. The factors analyzed were the number of commits and committers per release, the average size of the commits and the size of the system in each release. The main conclusion obtained from the study is that, while the number of commits and committers and the system size do not significantly affect cloning, larger commits lead to a higher cloning ratio. These insights contribute to predicting and preventing code cloning, thus enabling a software quality improvement.