When studying the research literature, one comes out with the impression that code search engines have become an essential software development tool that developers use regularly to accomplish their daily tasks. Driven by this impression, researchers primarily focus on improving the performance of code search. Nevertheless, as we argue in this paper, this impression is mostly unfounded. As a result, developers and researchers hold dissimilar perspectives on what code search engines are and their most important characteristics, with developers’ expectations and the state of the art often diverging widely.

This paper aims at reconciling these divergent perspectives by drawing a comprehensive picture of code search engines, as reflected in developers’ experiences and expectations as well as the state of the art. To that end, we first survey more than 100 software developers to ascertain their usages of and preferences for code search engines. We then review the state of the art on this topic by analyzing academic papers, industry releases, and open-source projects. Finally, we juxtapose the results of our two investigations to synthesize a call-for-action for researchers and industry practitioners to better meet the demands of software developers when it comes to searching for code. Our findings can be used to better align the state of the art and practice of code search engines, leading to wider adoption and more effective use of this powerful software development tool.