How developers search for code: a case study

Abstract

With the advent of large code repositories and sophisticated search capabilities, code search is increasingly becoming a key software development activity. In this work we shed some light into how developers search for code through a case study performed at Google, using a combination of survey and log-analysis methodologies. Our study provides insights into what developers are doing and trying to learn when performing a search, search scope, query properties, and what a search session under different contexts usually entails. Our results indicate that programmers search for code very frequently, conducting an average of five search sessions with 12 total queries each workday. The search queries are often targeted at a particular code location and programmers are typically looking for code with which they are somewhat familiar. Further, programmers are generally seeking answers to questions about how to use an API, what code does, why something is failing, or where code is located.

Understanding the impact of support for iteration on code search

“…Often, they make decisions related to design (features they think are needed or other design decisions). These reasons might, in part, explain some of the iterative search behavior we observed in our experiments and that were observed by others as well [7], [13], [48], [50], [97], [106], because making design decisions is often argued to be an iterative process [2,46]. However, often programmers found code simply because they felt it satisfied requirements.…”

“…Problem solving and cognitive processes often do not have clear goals initially, but become clearer over time, which implies the goal driving the search can be initially unclear and changing [24], [27], [120]. [97], where code is found to then change for debugging, refactoring, or other maintenance tasks [34], [61], [112]. In contrast, searching on the Internet, code is found to support different cognitive processes (sometimes referred to as discovering requirements [36]) or sometimes used as-is.…”

“…Surveys asking programmers why they search for code on the Internet have been conducted by Sim et al [107], Sadowski et al [97], Stolee et al [116], and Hucka and Graham [53]. In Sim et al's survey, all 69 participants reported that they searched on the Internet either for code to use as a reference or for code that they can use as-is.…”

“…Given the advantages and disadvantages of search engines today and the importance of search in developing software (programmers report searching for code frequently as part of their practice [97], [108]), software engineering researchers are investigating how to improve code search engines. Some, for instance, have been investigating how to support more expressive queries (e.g., searching by test case or method signatures) that afford more precise matching of code compared to keywords (e.g., [4], [15], [54], [65], [71], [82], [91], [110], [122], [142]).…”

Augmenting and structuring user queries to support efficient free-form code search

“…Code search is an important activity in software development since developers are regularly searching [40] for code examples dealing with diverse programming concepts, APIs, and specific platform peculiarities. Such examples can indeed help them practice programming against a library and platform, or they can immediately be used for inspiration in software development tasks.…”