A Study and Toolkit for Asynchronous Programming in C#

Asynchronous programming is in demand today, because re-sponsiveness is increasingly important on all modern devices. Yet, we know little about how developers use asynchronous programming in practice. Without such knowledge, devel-opers, researchers, language and library designers, and tool providers can make wrong assumptions. We present the first study that analyzes the usage of asyn-chronous programming in a large experiment. We analyzed 1378 open source Windows Phone (WP) apps, comprising 12M SLOC, produced by 3376 developers. Using this data, we answer 2 research questions about use and misuse of asyn-chronous constructs. Inspired by these findings, we developed (i) Asyncifier, an automated refactoring tool that converts callback-based asynchronous code to use async/await; (ii) Corrector, a tool that finds and corrects common misuses of async/await. Our empirical evaluation shows that these tools are (i) applicable and (ii) efficient. Developers accepted 314 patches generated by our tools