Developers change source code to add new functionality, fix bugs, or refactor their code. Many of these changes have immediate impact on quality or stability. However, some impact of changes may become evident only in the long term. This thesis makes use of change genealogy dependency graphs modeling dependencies between code changes capturing how earlier changes enable and cause later ones. Using change genealogies, it is possible to apply formal methods like model checking on version archives
When interacting with version control systems, developers often commit unrelated or loosely related code changes in a single transaction. When analyzing the version history, such tangled changes will make all changes to all modules appear related, possibly compromising the resulting analyses through noise and bias. In an investigation of five open-source JAVA projects, we found
Hadley Wickham's ggplot2 R package is a very powerful and excellent package. And although the documentation of the package is excellent, things can get complicated. This post explains how to create an advanced boxplot grid that allows to compare multiple measurements collected over multiple projects based on different features. Rahul Premraj and I used a similar plot to present result in one of our papers.
In a manual examination of more than 7,000 issue reports from the bug databases of five open-source projects, we found 33.8% of all issue reports to be misclassified, that is, rather than referring to a code fix, they resulted in a new feature, an update to documentation, or an internal refactoring. This misclassification introduces bias [...]
Fuzz testing is an automated technique providing random data as input to a software system in the hope to expose a vulnerability. In order to be effective, the fuzzed input must be common enough to pass elementary consistency checks; a JavaScript interpreter, for instance, would only accept a semantically valid program. On the other hand, [...]
Google has many products and projects. The problem is that for many projects, the current version is deprecated and the new one not ready yet. For GData, Google’s library to access core API infrastructure such as Google’s project hosting services is not getting maintained anymore. For me this is a major drawback since APIs are [...]
When plotting contribution shares, pie charts seem to be logic. But pie charts look ugly and do not add much more information than presenting the data in a table. But there is an alterative: stacker bar charts. In R you can use the ggplot2 package to plot them easily. Below, you find the very same [...]
