Understanding Stack Overflow Code Fragments

Code fragments posted in answers on Q&A forums can form an important source of developer knowledge. However, effective reuse of code fragments found online often requires information other than the code fragment alone. We report on the results of a survey-based study to investigate to what extent developers perceive Stack Overflow code fragments to be self-explanatory. As part of the study, we also investigated the types of information missing from fragments that were not self-explanatory. We find that less than half of the Stack Overflow code fragments in our sample are considered to be self-explanatory by the 321 participants who answered our survey, and that the main issues that negatively affect code fragment understandability include incomplete fragments, code quality, missing rationale, code organization, clutter, naming issues, and missing domain information. This study is a step towards understanding developers' information needs as they relate to code fragments, and how these needs can be addressed.