Large language models trained on massive code corpora can generalize to new tasks without the need for task-specific fine-tuning. In few-shot learning, these models take as input a prompt, composed of natural language instructions, a few instances of task demonstration, and a query and generate an output. However, the creation of an effective prompt for code-related tasks in few-shot learning has received little attention. We present a technique for prompt creation that automatically retrieves code demonstrations similar to the developer task, based on embedding or frequency analysis. We apply our approach, Cedar, to two different programming languages, statically and dynamically typed, and two different tasks, namely, test assertion generation and program repair. For each task, we compare Cedar with state-of-the-art task-specific and fine-tuned models. The empirical results show that, with only a few relevant code demonstrations, our prompt creation technique is effective in both tasks with an accuracy of 76% and 52% for exact matches in test assertion generation and program repair tasks, respectively. For assertion generation, Cedar outperforms existing task-specific and fine-tuned models by 333% and 11%, respectively. For program repair, Cedar yields 189% better accuracy than task-specific models and is competitive with recent fine-tuned models. These findings have practical implications for practitioners, as Cedar could potentially be applied to multilingual and multitask settings without task or language-specific training with minimal examples and effort.

Deep learning-based program repair has received significant attention from the research community lately. Most existing techniques treat source code as a sequence of tokens or abstract syntax trees. Consequently, they cannot incorporate semantic contextual information pertaining to a buggy line of code and its fix. In this work, we propose a program repair technique called GLANCE that combines static program analysis with graph-to-sequence learning for capturing contextual information. To represent contextual information, we introduce a graph representation that can encode information about the buggy code and its repair ingredients by embedding control and data flow information. We employ a fine-grained graphical code representation, which explicitly describes code change context and embeds semantic relationships between code elements. GLANCE leverages a graph neural network and a sequence-based decoder to learn from this semantic code representation. We evaluated our work against six state-of-the-art techniques, and our results show that GLANCE fixes 52% more bugs than the best performing technique.

Contextual information plays a vital role for software developers when understanding and fixing a bug. Consequently, deep learning based program repair techniques leverage context for bug fixes. However, existing techniques treat context in an arbitrary manner, by extracting code in close proximity of the buggy statement within the enclosing file, class, or method, without any analysis to find actual relations with the bug. To reduce noise, they use a predefined maximum limit on the number of tokens to be used as context. We present a program slicing based approach, in which instead of arbitrarily including code as context, we analyze statements that have a control or data dependency on the buggy statement. We propose a novel concept called dual slicing , which leverages the context of both buggy and fixed versions of the code to capture relevant repair ingredients. We present our technique and tool called Katana , the first to apply slicing-based context for a program repair task. The results show that Katana effectively preserves sufficient information for a model to choose contextual information while reducing noise. We compare against four recent state-of-the-art context-aware program repair techniques. Our results show that Katana fixes between 1.5 and 3.7 times more bugs than existing techniques.