Security-based code smell definition, detection, and impact quantification in Android

Android occupies a high market share, and its broad functions make Android security matter. Research reveals that many security issues are caused by insecure coding practices. As a poor design indicator, code smell threatens the safety and quality assurance of Android applications (apps). Although previous works revealed specific problems associated with code smells, the field still lacks research reflecting Android features. Moreover, the cost and time limit developers to repairing numerous smells timely. We conducted a study, including definition, detection, and impact quantification for Android code smell (DefDIQ): (1) define 15 novel code smells in Android from a security programming perspective; meanwhile, we provide suggestions on how to eliminate or mitigate them; (2) implement DACS to automatically detect the custom code smells based on ASTs; (3) investigate the correlation between individual smells with DACS detection results, and select suitable code smells to construct fault counting models, then quantify their impact on quality, and thereby generating code smell repair priorities. We conducted experiments on 4,575 open-source apps, and the findings are: (i) Lin’s CCC between DACS and manual detection results reaches 0.9994, verifying the validity; (ii) the fault counting model constructed by ZINB is superior to NB (AIC = 517.32, BIC = 522.12); some smells do indicate fault-proneness, and we identify such avoidable poor designs; (iii) different code smells have different importance and the repair priorities constructed provide a practical guideline for researchers and inexperienced developers.