Constructing universal version history

ABSTRACT

Developers often copy code for parts or entire products to start a new product or a new release. In order to understand the software change history and to determine the code authorship, we propose to construct a universal version history from multiple version control repositories. To that end we create two practical code copy detection methods at the level of the source code file: prefix-postfix algorithm and prefix algorithm. The full pathname of a file and its version history are used to construct the universal version history of a file by linking together change histories of files that had the same code at any point in the past. The assumption of both algorithms is that developers often duplicate files by copying entire directories. Once the copying is identified we propose an algorithm to link version histories from multiple repositories in order to construct universal version history. The results show that about 41.32% of source files (in the repository involving more than 6M versions of around 2M files) were duplicated among the Avaya's source code repositories for more than ten different projects. The prefix-postfix algorithm is more suitable than prefix algorithm due to the reasonable error rates after validation of the known copying behaviors.

REFERENCES

• 1: B. S. Baker, On finding duplication and near-duplication in large software systems, Proceedings of the Second Working Conference on Reverse Engineering, p.86, July 14-16, 1995
• 2: Bruno Lague , Daniel Proulx , Jean Mayrand , Ettore M. Merlo , John Hudepohl, Assessing the Benefits of Incorporating Function Clone Detection in a Development Process, Proceedings of the International Conference on Software Maintenance, p.314, October 01-03, 1997
• 3: Akito Monden , Daikai Nakae , Toshihiro Kamiya , Shin-ichi Sato , Ken-ichi Matsumoto, Software Quality Analysis by Code Clones in Industrial Legacy Software, Proceedings of the 8th International Symposium on Software Metrics, p.87, June 04-07, 2002
• 4: Ira D. Baxter , Andrew Yahin , Leonardo Moura , Marcelo Sant'Anna , Lorraine Bier, Clone Detection Using Abstract Syntax Trees, Proceedings of the International Conference on Software Maintenance, p.368, March 16-19, 1998
• 5: Stéphane Ducasse , Matthias Rieger , Serge Demeyer, A Language Independent Approach for Detecting Duplicated Code, Proceedings of the IEEE International Conference on Software Maintenance, p.109, August 30-September 03, 1999
• 6: Toshihiro Kamiya , Shinji Kusumoto , Katsuro Inoue, CCFinder: a multilinguistic token-based code clone detection system for large scale source code, IEEE Transactions on Software Engineering, v.28 n.7, p.654-670, July 2002 [doi>10.1109/TSE.2002.1019480]
• 7: Cory Kapser , Michael W. Godfrey, Improved Tool Support for the Investigation of Duplication in Software, Proceedings of the 21st IEEE International Conference on Software Maintenance (ICSM'05), p.305-314, September 25-30, 2005 [doi>10.1109/ICSM.2005.52]

INDEX TERMS

Primary Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.7 Distribution, Maintenance, and Enhancement
          Subjects: Restructuring, reverse engineering, and reengineering

General Terms:
Algorithms, Measurement

Keywords:
change history, cloning, code authorship, code copying, version control