Quieting the Static: A Study of Static Analysis Alert Suppressions

Static analysis tools are commonly used to detect defects before the code is released. Previous research has focused on their overall effectiveness and their ability to detect defects. However, little is known about the usage patterns of warning suppressions: the configurations developers set up in order to prevent the appearance of specific warnings. We address this gap by analyzing how often are warning suppression features used, which warning suppression features are used and for what purpose, and also how could the use of warning suppression annotations be avoided. To answer these questions we examine 1\,425 open-source Java-based projects that utilize Findbugs or Spotbugs for warning-suppressing configurations and source code annotations. We find that although most warnings are suppressed, only a small portion of them get frequently suppressed. Contrary to expectations, false positives account for a minor proportion of suppressions. A significant number of suppressions introduce technical debt, suggesting potential disregard for code quality or a lack of appropriate guidance from the tool. Misleading suggestions and incorrect assumptions also lead to suppressions. Findings underscore the need for better communication and education related to the use of static analysis tools, improved bug pattern definitions, and better code annotation. Future research can extend these findings to other static analysis tools, and apply them to improve the effectiveness of static analysis.