Repairing Event Race Errors by Controlling Nondeterminism

TY - GEN

T1 - Repairing Event Race Errors by Controlling Nondeterminism

AU - Adamsen, Christoffer Quist

AU - Møller, Anders

AU - Karim, Rezwana

AU - Sridharan, Manu

AU - Tip, Frank

AU - Sen, Koushik

N1 - Conference code: 39

PY - 2017/5/20

Y1 - 2017/5/20

N2 - Modern web applications are written in an event-driven style, in which event handlers execute asynchronously in response to user or system events. The nondeterminism arising from this programming style can lead to pernicious errors. Recent work focuses on detecting event races and classifying them as harmful or harmless. However, since modifying the source code to prevent harmful races can be a difficult and error-prone task, it may be preferable to steer away from the bad executions. In this paper, we present a technique for automated repair of event race errors in JavaScript web applications. Our approach relies on an event controller that restricts event handler scheduling in the browser according to a specified repair policy, by intercepting and carefully postponing or discarding selected events. We have implemented the technique in a tool called EventRaceCommander, which relies entirely on source code instrumentation, and evaluated it by repairing more than 100 event race errors that occur in the web applications from the largest 20 of the Fortune 500 companies. Our results show that application-independent repair policies usually suffice to repair event race errors without excessive negative impact on performance or user experience, though application-specific repair policies that target specific event races are sometimes desirable.

AB - Modern web applications are written in an event-driven style, in which event handlers execute asynchronously in response to user or system events. The nondeterminism arising from this programming style can lead to pernicious errors. Recent work focuses on detecting event races and classifying them as harmful or harmless. However, since modifying the source code to prevent harmful races can be a difficult and error-prone task, it may be preferable to steer away from the bad executions. In this paper, we present a technique for automated repair of event race errors in JavaScript web applications. Our approach relies on an event controller that restricts event handler scheduling in the browser according to a specified repair policy, by intercepting and carefully postponing or discarding selected events. We have implemented the technique in a tool called EventRaceCommander, which relies entirely on source code instrumentation, and evaluated it by repairing more than 100 event race errors that occur in the web applications from the largest 20 of the Fortune 500 companies. Our results show that application-independent repair policies usually suffice to repair event race errors without excessive negative impact on performance or user experience, though application-specific repair policies that target specific event races are sometimes desirable.

KW - JavaScript, automated repair, event-driven programming

UR - http://www.scopus.com/inward/record.url?scp=85027720002&partnerID=8YFLogxK

U2 - 10.1109/ICSE.2017.34

DO - 10.1109/ICSE.2017.34

M3 - Article in proceedings

SN - 978-1-5386-3868-2

SP - 289

EP - 299

BT - Proceedings - 2017 IEEE/ACM 39th International Conference on Software Engineering, ICSE 2017

PB - IEEE Press

CY - Piscataway, NJ, USA

T2 - 39th International Conference on Software Engineering

Y2 - 20 May 2017 through 28 May 2017

ER -