Presented By : Abirami Poonkundran

1. Software Dependencies, Work Dependencies, and their impact on FailuresJeffrey A.Roberts, James D.Herbsleb, Marcelo cataldo and AudrisMockus Presented By : AbiramiPoonkundran

2. Concept • This paper is a case study on the impact of • Syntactic Dependencies, • Logical Dependencies and • Work Dependencies on a software development project, and identifies which dependencies have the higher impact on fault proneness

3. Overview • Introduction • Software Dependencies • Syntactic Dependencies • Logical Dependencies • Work Dependencies • Data Collection • Measuring Failure • Results • Conclusion • Pro’s and Con’s

4. Introduction • Research has shown that software faults are caused by violation of dependencies • Dependencies could be: • Software Dependencies • Technical • Caused by developers • Work Dependencies • Organizational • Caused by how work is organized • This paper examines the relative impact that each of these dependencies have on the fault proneness of the software system

5. Software Dependencies • Software Dependencies could be: • Syntactic • Logical

6. Syntactic Dependencies • Focuses on Control and Dataflow relationships • Dependencies are discovered by analysis of source code or from an intermediate representation like byte code or syntax trees • These dependencies could be: • Data Related Dependency - e.g., a particular data structure modified by a function and used in another function • Functional Dependency – e.g., Method A calls Method B

7. Logical Dependencies • Dependencies between the source code files of a system that are changed together as part of software development • Often Logical Dependencies provide more valuable information than Syntactic Dependencies (eg., in Remote Procedure Calls) • They can identify important dependencies that are not visible in Syntactic Code analysis

8. Work Dependencies • Only recent research have started shedding light on the impact of human and organizational factors on the failure proneness of software systems • Caused because of lack of proper communication and coordination between developers • Research have shown that identification and management of work dependencies is a major challenge

9. Data Collection (1) • Examined two large software development projects: • Project A • Complex distributed system • Data are covered for 3 years of development activity • The company had 114 developers grouped into 8 development team and has 3 development locations • ≃ 5 million lines of code distributed in 7,737 source code files in C language

10. Data Collection (2) • Project B: • Embedded software system • 40 developers in the project over a period of 5 years • 1.2 million lines of code were used in both C and C++ language

11. Data Collection (3) • In both projects, every change to source code was controlled by Modification Requests (MR) • Every change made to Source code has to be committed to Version Control System • Information Used for this Analysis: • Collected a total of 8,257 and 3,372 MRs for Project A and Project B • Version control system from both projects • The source code itself from both projects

12. Measuring Failure • Goal is to investigate failure proneness at the file level • File Buggyness– indicates whether a file has been modified in the course of resolving a defect

13. Syntactic Dependencies • Used C-REX tool to identify programming language tokens and references in each entity of each source-code file • Source code snap shot was taken every quarter • Syntactic dependency analysis was done for each source code snapshot • Syntactic dependencies between source code file was identified by data, function and method references

14. Logical Dependencies • Relate source-code files that are modified together as part of an MR • If only one file was changed for an MR, then there is no dependencies • Using the Commit information from the Version control system, a logical dependency matrix (LDM) was created • LDM is a symmetric matrix of source-code files where Cij represents the sum, across all releases, of the number of times files i and j were changed together as part of an MR

15. Work Dependencies • Used two measures: • Workflow Dependencies • Captures the temporal aspects of the development effort • Two developers i and j are said to be interdependent if the MR was transferred from one developer i to developer j some point during that MR • Coordination Requirements • Captures the intradeveloper coordination requirements • Uses two matrix: • Task Assignment Matrix – Developer to file matrix • Task Dependency Matrix – File to file matrix

16. Results • Analysis consists of two stages: • First Stage: Focus on examining the relative impact of each dependency type on failure proneness of source-code files • Second Stage: Verified the consistency of the initial results by conduction a number of confirmatory analysis • Constructed several logistic regression models

17. Results

18. Results

19. Results • If Odds Ratio is larger than 1, then positive relationship between the independent and dependent variables • If Odds ratio less than 1, then negative relationship • Model 1: • Based on LOC and Average Lines Changed • LOC is positively associated with failure proneness • Average lines changed is also positively associated with defects

20. Results • Model II: • Introduces Syntactic Dependency measures by: • Inflow Data • Has significant impact on error proneness • Inflow Functional • This type of syntactic dependency has less impact on failure pronenesss • Model III: • Higher number of logical dependencies related to an increase in the likelihood of failure

21. Results • Model IV: • Workflow dependencies do increase the likelihood of defects • Model V: • Coordination requirement has an higher impact in Project A and lesser impact in Project B

22. Conclusion • All dependencies increases fault proneness • Logical Dependencies has the highest impact, followed by Workflow dependencies and then Syntactic Dependencies

23. Strength: • Analysis is based on data collection from 2 projects • Logical Dependencies has the highest impact when compared to other 2 dependencies Weakness: • Data collection from only 2 projects • They have not mentioned about other dependencies except software and work dependencies • Not provided a method to solve the errors for the dependencies

24. Suggestions • Need to provided a method to solve the errors for the dependencies • Discussion about other dependencies • General concepts should be introduced