ChangeWiki: Repository-Level Change Summarization Augmented with Architecture Semantics

Abstract

Understanding software evolution at the repository level is essential for tasks such as release management, code review, and regression testing. However, existing change summarization techniques are largely confined to single commits or functions, failing to capture cross-commit evolutionary context, while recent repository-level understanding tools focus on static documentation of single-version codebases, overlooking evolution over time. To bridge this gap, we propose ChangeWiki, an architecture semantic-augmented approach for repository-level change summarization. ChangeWiki first constructs hierarchical, multi-granularity change entity trees enriched with multi-source contexts to infer change intent and impact. It then recovers modular structures across versions and employs a bidirectional context-guided aggregation mechanism, synthesizing code-level changes from the bottom up while injecting architectural semantics as top-down constraints. ChangeWiki finally generates coherent, traceable summaries that capture both local modifications and system-level evolution. We construct comprehensive benchmarks and evaluate ChangeWiki on real-world projects. Experimental results demonstrate significant improvements in semantic accuracy, completeness, and cross-granularity traceability. A prototype of ChangeWiki has been deployed in an industrial setting for upstream-downstream code evolution, where developers reported that the hierarchical summaries significantly reduced manual effort in issue localization caused by upstream changes and show potential for automating version release notes.