Evolution of dynamic feature usage in PHP

Abstract

PHP includes a number of dynamic features that, if used, make it challenging for both programmers and tools to reason about programs. In this paper we examine how usage of these features has changed over time, looking at usage trends for three categories of dynamic features across the release histories of two popular open-source PHP systems, WordPress and MediaWiki. Our initial results suggest that, while features such as eval are being removed over time, more constrained dynamic features such as variable properties are becoming more common. We believe the results of this analysis provide useful insights for researchers and tool developers into the evolving use of dynamic features in real PHP programs.

Challenges for Static Analysis of Java Reflection - Literature Review and Empirical Study

“…To implement pattern detectors we used the builtin AST pattern matching and traversal facilities of Rascal [59], which have been used in many other projects [60]- [62]. The pattern code is around 150 SLOC and it is openly available [63].…”

“…Parnin et al have studied adoption of Java generics [70], Pinto et al studied concurrent programming constructs [71], and Dyer et al studied features prior to their official release [72]. Similar studies have also been conducted, e.g., for C# [73] and PHP [60].…”

Enabling PHP software engineering research in Rascal

“…Later empirical work has focused on how WordPress plugins are used in practice and on how the use of dynamic language features has changed in WordPress and in MediaWiki across the version history of each system [14]. The work on program analysis described below also includes a strong empirical component, using an updated version of the original 1 // 1.…”

“…Built using the Rascal meta-programming language [10], a successor to Asf+Sdf [11] and RScript [12], PHP AiR has been, and is currently being, used in multiple research projects, including: empirical surveys of PHP language feature usage [13] and of the evolution of language feature usage over time [14]; a program analysis for resolving dynamic file includes [15]; a program analysis for resolving names used in reflective contexts in PHP code [16]; a refactoring from hand-coded SQL calls to uses of database libraries [17]; and multiple student projects to extract various metrics from PHP source code.…”

“…That paper focused mainly on uses of PHP AiR, spending very little time on the implementation, while this paper instead focuses on the implementation choices made and what can be learned from them. Several other papers [13][14][15][16] describe specific uses of PHP AiR, including empirical studies of how PHP is used and program analysis algorithms focused on specific dynamic language features. This paper is a longer version of an unpublished paper presented at the 4th International Workshop on Academic Software Development Tools and Techniques in 2013.…”