Takashi Ishio

Source file set search for clone-and-own reuse analysis

Clone-and-own approach is a natural way of source code reuse for software developers. To assess how known bugs and security vulnerabilities of a cloned component affect an application, developers and security analysts need to identify an original version of the component and understand how the cloned component is different from the original one. Although developers may record the original version information in a version control system and/or directory names, such information is often either unavailable or incomplete. In this research, we propose a code search method that takes as input a set of source files and extracts all the components including similar files from a software ecosystem (i.e., a collection of existing versions of software packages). Our method employs an efficient file similarity computation using b-bit minwise hashing technique. We use an aggregated file similarity for ranking components. To evaluate the effectiveness of this tool, we analyzed 75 cloned components in Firefox and Android source code. The tool took about two hours to report the original components from 10 million files in Debian GNU/Linux packages. Recall of the top-five components in the extracted lists is 0.907, while recall of a baseline using SHA-1 file hash is 0.773, according to the ground truth recorded in the source code repositories.

How is IF Statement Fixed Through Code Review? A Case Study of Qt Project

Peer code review is key to ensuring the absence of software defects. To improve the review process, many code review tools provide OSS(Open Source Software) project CI(Continuous Integration) tests that automatically verify code quality issues such as a code convention issues. However, these tests do not cover project policy issues and a code readability issues. In this study, our main goal is to understand how a code owner fixes conditional statement issues based on reviewers feedback. We conduct an empirical study to understand if statement changes after review. Using 69,325 review requests in the Qt project, we analyze changes of the if conditional statements that (1) are requested to be reviewed, and (2) that are implemented after review. As a result, we find the most common symbolic changes are ( and ) (35%), ! operator (20%) and -> operator (12%). Also, ! operator is frequently replaced with ( and ).