  Python has become one of the most popular programming languages for software
development due to its simplicity, readability, and versatility. As the Python
ecosystem grows, developers face increasing challenges in avoiding module
conflicts, which occur when different packages have the same namespace modules.
Unfortunately, existing work has neither investigated the module conflict
comprehensively nor provided tools to detect the conflict. Therefore, this
paper systematically investigates the module conflict problem and its impact on
the Python ecosystem. We propose a novel technique called InstSimulator, which
leverages semantics and installation simulation to achieve accurate and
efficient module extraction. Based on this, we implement a tool called
ModuleGuard to detect module conflicts for the Python ecosystem. For the study,
we first collect 97 MC issues, classify the characteristics and causes of these
MC issues, summarize three different conflict patterns, and analyze their
potential threats. Then, we conducted a large-scale analysis of the whole PyPI
ecosystem (4.2 million packages) and GitHub popular projects (3,711 projects)
to detect each MC pattern and analyze their potential impact. We discovered
that module conflicts still impact numerous TPLs and GitHub projects. This is
primarily due to developers' lack of understanding of the modules within their
direct dependencies, not to mention the modules of the transitive dependencies.
Our work reveals Python's shortcomings in handling naming conflicts and
provides a tool and guidelines for developers to detect conflicts.
