An investigation of misunderstanding code patterns in C open-source software projects

Maintenance consumes 40% to 80% of software development costs. So, it is essential to write source code that is easy to understand to reduce the costs with maintenance. Improving code understanding is important because developers often mistake the meaning of code, and misjudge the program behavior, which can lead to errors. There are patterns in source code, such as operator precedence, and comma operator, that have been shown to influence code understanding negatively. Despite initial results, these patterns have not been evaluated in a real-world setting, though. Thus, it is not clear whether developers agree that the patterns studied by researchers can cause substantial misunderstandings in real-world practice. To better understand the relevance of misunderstanding patterns, we applied a mixed research method approach, by performing repository mining and a survey with developers, to evaluate misunderstanding patterns in 50 C open-source projects, including Apache, OpenSSL, and Python. Overall, we found more than 109K occurrences of the 12 patterns in practice. Our study shows that according to developers only some patterns considered previously by researchers may cause misunderstandings. Our results complement previous studies by taking the perception of developers into account.