SemanticForge: Repository-Level Code Generation through Semantic Knowledge Graphs and Constraint Satisfaction

Abstract

Large language models (LLMs) have transformed software development by enabling automated code generation, yet they frequently suffer from systematic errors that limit practical deployment. We identify two critical failure modes: \textit{logical hallucination} (incorrect control/data-flow reasoning) and \textit{schematic hallucination} (type mismatches, signature violations, and architectural inconsistencies). These errors stem from the absence of explicit, queryable representations of repository-wide semantics.

This paper presents \textbf{\framework}, a novel framework for code generation that addresses these limitations through knowledge graph-guided constraint satisfaction. Our approach proceeds in four integrated stages: (1) constructing heterogeneous repository knowledge graphs that capture both static analysis and dynamic execution traces; (2) learning neural query planners that extract task-relevant context from these graphs; (3) employing satisfiability modulo theories (SMT)-guided beam search to ensure generated code satisfies semantic constraints; and (4) maintaining graph fidelity through continual incremental updates.

Our comprehensive evaluation on \dataset, a curated benchmark of 4,250 repository-level tasks across 50 Python projects, demonstrates significant improvements over state-of-the-art baselines: 49.8\% Pass@1 (18.1\% absolute improvement), 52\% reduction in schematic hallucination, and 31\% reduction in logical hallucination. Cross-repository generalization analysis shows strong transfer capabilities with only 4.3\% average performance degradation across architectural patterns. These results establish new benchmarks for repository-level code generation while providing theoretical foundations and practical tools for semantically-aware automated software development.

The explicit semantic representation and constraint satisfaction framework introduced in \framework\ enables more reliable automated development tools and provides a foundation for future advances in AI-assisted software engineering.