The paper "Poison Valleys: Diagnosing Path-Dependent Failure in LLM Code Repair" investigates why large language model (LLM) code‑repair agents sometimes produce incorrect patches. By analyzing 1,844 model requests on two synthetic Python tasks—PersistQueue and Dijkstra—the authors trace how misconceptions in a model’s hypothesis or implementation plan lead to specific software obligation violations. They find that shifting a misconception from hypothesis to plan increases failure rates by roughly 30% for both tasks, revealing distinct, model‑dependent failure patterns linked to upstream misunderstandings.
arXiv:2607. 04537v1 Announce Type: cross Abstract: Code language models are now trusted collaborators in production workflows for debugging, refactoring, and iterative repair, and every benchmark that evaluates them assumes the instructions they act on are correct.
Code language models are now trusted collaborators in production workflows for debugging, refactoring, and iterative repair, and every benchmark that evaluates them assumes the instructions they act on are correct. We study what happens when that assumption breaks.
The paper introduces rebuild‑dossier, an open‑source tool that locks an application’s real interface before code is written and enforces one‑test‑at‑a‑time building through automated checks. In experiments, a compliant agent failed a held‑back test while a rule‑breaking agent passed, showing that a passing test suite can be gamed. The study also demonstrates that the automated check mechanism, rather than interface‑locking alone, is crucial for reliable rebuilds, and that multi‑level verification catches errors that single‑level checks miss.
The paper investigates hallucination in large language model–based automated program repair (APR). It defines hallucination as producing patches or intermediate artifacts that are not grounded in available repair evidence, and analyzes it across final patches and intermediate tasks such as triggering test case identification, line coverage prediction, and additional test case generation. Experiments on 832 Defects4J bugs show that only 21.0%–55.9% of patches pass the developer test suite, with 72.7% of sampled repairs exhibiting hallucinations, often due to incorrect causal localization or repair strategies.
arXiv:2608. 14863v1 Announce Type: cross Abstract: LLM-based coding agents have advanced rapidly on single-process SWE tasks, with frontier models now clustering in the high-70s on SWE-bench Verified.
arXiv:2609.05881v1 Announce Type: cross Abstract: Developers increasingly run large language models locally by pulling quantized GGUF artifacts from public registries, yet nothing in the distribution...
arXiv:2607. 11098v1 Announce Type: cross Abstract: Tool-using LLM agents are mostly evaluated assuming all tools work.
The paper introduces PLLM+, a hybrid pipeline for resolving Python dependency conflicts that combines deterministic steps—such as static AST inference, replaying known successful configurations from a solutions database, and live PyPI validation—with an LLM-based repair fallback. Evaluated on the HG2.9K benchmark of 2,891 failing snippets, PLLM+ successfully fixes 1,500 cases, outperforming the baseline PLLM and reducing average runtime from 368.7 to 71.8 seconds per snippet. The majority of fixes (1,495) come from replaying existing configurations, while the LLM fallback contributes only five additional solutions.
HAFixAgent is a history-aware program repair agent that incorporates blame-derived repository context into its repair loop. In a large-scale study on 854 Defects4J and 501 BugsInPy bugs, the agent’s best history heuristic improved repair rates by up to +64.3% with weaker models and outperformed existing agents by significant margins. The three complementary history heuristics together repair more bugs than any single heuristic, with only modest increases in agent steps or tokens.
arXiv:2607. 19843v1 Announce Type: cross Abstract: Large language models (LLMs) have made automated program repair (APR) increasingly practical for real-world bugs, but repairing directly from bug reports remains underconstrained.
arXiv:2607. 24604v1 Announce Type: cross Abstract: Generate--test--revise loops are common in coding agents, but repetition alone provides no reliability guarantee.
SWE‑Gate is a new repository‑level benchmark that evaluates software engineering agents on both functional correctness and review‑derived acceptance constraints. It creates 303 repair instances from real pull‑request review comments across 75 open‑source Python projects, providing separate functional and constraint tests along with compliant and non‑compliant patches. Experiments with four LLM backends show that while 644 repairs pass functional tests, 221 fail to meet the review constraints, highlighting a gap between functional success and full repair compliance.