Presented By : Abirami Poonkundran

 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

 Introduction  Software Dependencies ◦ Syntactic Dependencies ◦ Logical Dependencies ◦ Work Dependencies  Data Collection  Measuring Failure  Results  Conclusion  Pro’s and Con’s

 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

 Software Dependencies could be: ◦ Syntactic ◦ Logical

 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

 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

 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

 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

◦ 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

 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

 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

 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

 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

 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

 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

 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

 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

 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

 All dependencies increases fault proneness  Logical Dependencies has the highest impact, followed by Workflow dependencies and then Syntactic Dependencies

 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

 Need to provided a method to solve the errors for the dependencies  Discussion about other dependencies  General concepts should be introduced