English

On Pretraining for Project-Level Code Completion

Software Engineering 2025-10-16 v1 Machine Learning

Abstract

Repository-level pretraining is commonly used to enable large language models for code to leverage codebase-wide context. This enhances their ability to generate accurate and context-aware code completions. In this work, we investigate how different repository-processing strategies affect in-context learning in OpenCoder, a 1.5B-parameter model. We extend its context window from 4,096 to 16,384 tokens by training on additional 1B tokens of curated repository-level data. Despite relying on a smaller dataset than competing models (which often use hundreds of billions of tokens), our model achieves comparable performance on the Long Code Arena benchmark. We find that various repository-processing techniques yield similarly strong results, with the primary gain coming from adapting to a new rotary positional embedding (RoPE) scaling parameter. Finally, we show that a simpler file-level training approach at the original sequence length remains highly effective, opening up repository-level code completion research to settings with more constrained data and compute resources.

Keywords

Cite

@article{arxiv.2510.13697,
  title  = {On Pretraining for Project-Level Code Completion},
  author = {Maksim Sapronov and Evgeniy Glukhov},
  journal= {arXiv preprint arXiv:2510.13697},
  year   = {2025}
}