Programmer-Friendly Refactoring Errors

Refactoring tools, common to many integrated development environments, can help programmers to restructure their code. These tools sometimes refuse to restructure the programmer's code, instead giving the programmer a textual error message that she must decode if she wishes to understand the reason for the tool's refusal and what corrective action to take. This paper describes a graphical alternative to textual error messages called Refactoring Annotations. It reports on two experiments, one using an integrated development environment and the other using paper mockups, that show that programmers can use Refactoring Annotations to quickly and accurately understand the cause of refactoring errors.

1 Introduction

Refactoring is the process of changing the structure of code without changing the way that it behaves [6]. Refactoring is considered a best practice when creating and maintaining software, and indeed, research suggests that programmers practice it regularly [16], [22]. Examples of refactoring include renaming a variable, moving a method from a superclass to its subclasses, and taking a few statements and extracting them into a new method. Each kind of refactoring has a name: These examples are called Rename, Push Down Method, and Extract Method [6].