Understanding Emojis in Useful Code Review Comments

Emojis and emoticons serve as non-verbal cues and are increasingly prevalent across various platforms, including Modern Code Review. These cues often carry emotive or instructive weight for developers. Our study dives into the utility of Code Review comments (CR comments) by scrutinizing the sentiments and semantics conveyed by emojis within these comments. To assess the usefulness of CR comments, we augment traditional ‘textual’ features and pre-trained embeddings with ‘emoji-specific’ features and pre-trained embeddings. To fortify our inquiry, we expand an existing dataset with emoji annotations, guided by existing research on GitHub emoji usage, and re-evaluate the CR comments accordingly. Our models, which incorporate textual and emoji-based sentiment features and semantic understandings of emojis, substantially outperform baseline metrics. The often-overlooked emoji elements in CR comments emerge as key indicators of usefulness, suggesting that these symbols carry significant weight. CCS CONCEPTS - Software and its engineering $\rightarrow$ Formal software verification; $\cdot$ Software Quality $\rightarrow$ Peer Code Review.