[2601.19066] Dynamic Cogeneration of Bug Reproduction Test in Agentic Program Repair

Computer Science > Software Engineering arXiv:2601.19066 (cs) [Submitted on 27 Jan 2026 (v1), last revised 31 Mar 2026 (this version, v2)] Title:Dynamic Cogeneration of Bug Reproduction Test in Agentic Program Repair Authors:Runxiang Cheng, Michele Tufano, José Cambronero, Renyao Wei, Sherry Shi, Grant Uy, Pat Rondon, Franjo Ivančić View a PDF of the paper titled Dynamic Cogeneration of Bug Reproduction Test in Agentic Program Repair, by Runxiang Cheng and 7 other authors View PDF HTML (experimental) Abstract:Bug Reproduction Tests (BRTs) have been used in many Automated Program Repair (APR) systems, primarily for validating promising fixes and aiding fix generation. In practice, when developers submit a patch, they often implement the BRT alongside the fix. Our experience deploying agentic APR reveals that developers similarly desire a BRT within AI-generated patches to increase their confidence. However, canonical APR systems tend to generate BRTs and fixes separately, and focus on producing only the fix in the final patch. In this paper, we study agentic APR in the context of cogeneration, where the APR agent is instructed to generate both a fix and a BRT in the same patch. We evaluate the effectiveness of different cogeneration strategies on 120 human-reported bugs at Google and characterize different cogeneration strategies by their influence on APR agent behavior. We develop and evaluate patch selectors that account for test change information to select patches with ...