The Missing Links: Bugs and Bug-fix Commits

Empirical studies of software defects rely on links between bug databases and program code repositories. This linkage is typically based on bug-fixes identified in manually-entered commit logs. Unfortunately, developers do not always report which commits perform bug-fixes. Prior work suggests that such links can be a biased sample of the entire population of fixed bugs. The validity of statistical hypotheses-testing based on linked data could well be affected by bias. Given the wide use of linked defect data, it is vital to gauge the nature and extent of the bias, and try to develop testable theories and models of the bias. To do this, we must establish ground truth: manually analyze a complete version history corpus, and nail down those commits that fix defects, and those that are not. This is a difficult task, requiring an expert to compare versions, analyze changes, find related bugs in the bug database, reverse-engineer missing links, and finally record their work for use later. This effort must be repeated for hundreds of commits to obtain a useful sample of reported and unreported bug-fix commits. We make several contributions. First, we present Linkageur, a tool to facilitate link reverse-engineering. Second, we evaluate this tool, engaging a core developer of the Apache Webserver project to exhaustively annotate over all five hundred commits that occurred during a six week period. Finally, we analyze this comprehensive data set, showing that there are serious and consequential problems in the data.

bachmann2010mlb.pdf
PDF file

In  SIGSOFT '10/FSE-18: Proceedings of the 16th ACM SIGSOFT Symposium on Foundations of Software Engineering

Publisher  Association for Computing Machinery, Inc.
Copyright © 2007 by the Association for Computing Machinery, Inc. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept, ACM Inc., fax +1 (212) 869-0481, or permissions@acm.org. The definitive version of this paper can be found at ACM’s Digital Library --http://www.acm.org/dl/.

Details

TypeInproceedings
> Publications > The Missing Links: Bugs and Bug-fix Commits