Understanding Solidity Event Logging Practices in the Wild

TL;DR

This study analyzes Solidity event logging practices in 2,915 GitHub projects, revealing diverse modification reasons, and provides insights and tools to improve logging efficiency and correctness in smart contract development.

Contribution

First quantitative analysis of Solidity event logging practices in real-world projects, identifying key patterns, issues, and implications for developers and tool builders.

Findings

High prevalence of independent event logging code modifications

Diverse reasons for event logging code changes, including bug fixes and gas optimization

Effective detection of gas-consuming logging issues in real projects

Abstract

Writing logging messages is a well-established conventional programming practice, and it is of vital importance for a wide variety of software development activities. The logging mechanism in Solidity programming is enabled by the high-level event feature, but up to now there lacks study for understanding Solidity event logging practices in the wild. To fill this gap, we in this paper provide the first quantitative characteristic study of the current Solidity event logging practices using 2,915 popular Solidity projects hosted on GitHub. The study methodically explores the pervasiveness of event logging, the goodness of current event logging practices, and in particular the reasons for event logging code evolution, and delivers 8 original and important findings. The findings notably include the existence of a large percentage of independent event logging code modifications, and the underlying reasons for different categories of independent event logging code modifications are diverse (for instance, bug fixing and gas saving). We additionally give the implications of our findings, and these implications can enlighten developers, researchers, tool builders, and language designers to improve the event logging practices. To illustrate the potential benefits of our study, we develop a proof-of-concept checker on top of one of our findings and the checker effectively detects problematic event logging code that consumes extra gas in 35 popular GitHub projects and 9 project owners have already confirmed the detected issues.