IMPACT OF CODE OWNERSHIP IMPACT OF CODE OWNERSHIP ON ATIPATTERNS - PowerPoint PPT Presentation

IMPACT OF CODE OWNERSHIP IMPACT OF CODE OWNERSHIP ON ATIPATTERNS ON ATIPATTERNS Stéphane BUNOD Engineering school student at Polytech’Montpellier 3 month internship Supervisor : Foutse KHOMH

OUTLINE OUTLINE  Context  Goal  Implementation  Results  Conclusion  Personal experience

CONTEXT CONTEXT  Foutse’s research interests  Developping techniques and tools to assess the quality of systems  Design patterns, design defects : their impact on the quality of systems and their evolution in systems  Foutse “Antipatterns are more fault prone” . 2012  Christian Bird. Don’t Touch My Code! Examining the Effects of Ownership on Software Quality. 2011

GOAL GOAL

IMPLEMENTATION – IMPLEMENTATION – EXISTING WORK EXISTING WORK  Previous work from Francis NAHM:  List of AntiPatterns for each version of the Argouml project (APs example : ComplexClass, LongMethod, LongParameterList)

IMPLEMENTATION – IMPLEMENTATION – COLLECT COLLECT  Collect information about the Argouml project:  SVN log

IMPLEMENTATION – IMPLEMENTATION – WHAT IS INTERESTING IN WHAT IS INTERESTING IN « « SVN LOG SVN LOG » »

IMPLEMENTATION – IMPLEMENTATION – KEEP INTERESTING INFORMATION KEEP INTERESTING INFORMATION  Get the list of contributors  Get the date of commits  Get the files/classes that had been modified

IMPLEMENTATION – IMPLEMENTATION – EVALUATE MAJOR CONTRIBUTOR RATE EVALUATE MAJOR CONTRIBUTOR RATE Major contributor: A developer who has made changes to a component and whose ownership is at or above X% is a major contributor to the component and a commit from such a developer is a major contribution.  3rd quartile of all contributors statistics on each classes : 71%

IMPLEMENTATION – IMPLEMENTATION – ADD INFORMATION OF MC ON EACH VERSION ADD INFORMATION OF MC ON EACH VERSION  Know the kind of contributor for each version on each class.  Add it beside the number of AntiPatterns on each version of each class.

IMPLEMENTATION – IMPLEMENTATION – WHAT THE CSV LOOKS LIKE WHAT THE CSV LOOKS LIKE

IMPLEMENTATION – IMPLEMENTATION – METHOD TO ESTIMATE THE EVOLUTION OF A CLASS METHOD TO ESTIMATE THE EVOLUTION OF A CLASS List of the occurrence of AntiPatterns for each class.  Example: [5, 3, 4, 4, 1, 2, 5] [0]: A-A-A-A-A-S [1]: D-D-A-A-D [2]: S-A-A-D [3]: A-A-D [4]: D-D [5]: D A = 11 ; D = 8 ; S = 2  A > D > S  This class is considered to have a global amelioration tendency

IMPLEMENTATION – IMPLEMENTATION – DIFFERENT CATEGORIES OF LIST DIFFERENT CATEGORIES OF LIST  Classes with only Major Contributor (MC) on each version of the project.  Classes without any MC.  Classes with a MC, only on the first version.  Classes with a developer who becomes MC after few versions without any.  Classes where there is no longer MC after few versions with a MC.

RESULTS RESULTS Only MC on Only MC No MC the 1st Become MC No longer MC version Stable 58% 73,63% 74,40% 87,13% 79,18% Amelioration 24% 11,55% 7,76% 1,98% 14,46% Degradation 18% 14,82% 20,84% 10,89% 6,36%

CONCLUSION CONCLUSION  Linus Law. “ Given a large enough developers, almost every problem will be characterized quickly and the fix will be obvious to someone “  AntiPatterns have the same characteristics of Bugs correlate with ownership.  Of course, this work should be reproduced on other projects.

PERSONAL EXPERIENCE PERSONAL EXPERIENCE  Lab experience  Met new people  Learnt Python language (enjoyed coding for once)  Not sure I would be a good researcher ^^