When Shared Worlds Break: Demystifying Defects in Multi-User Extended Reality Software Systems
Shuqing Li, Chenran Zhang, Binchang Li, Cuiyun Gao, Michael R. Lyu
TL;DR
The paper tackles the problem of defects in multi-user XR by conducting the first large-scale empirical study of 2,649 bug reports from diverse sources. It develops two comprehensive taxonomies—one for bug symptoms and another for root causes—revealing that synchronization issues and avatar anomalies are prevalent and that network/synchronization logic and session management are dominant root causes. It also analyzes the severe consequences (including system crashes and disconnections) and identifies privacy and health implications unique to multi-user XR contexts. The findings highlight that multi-user XR requires specialized testing, debugging, and platform support to manage the intertwined real-time networking, distributed state, and immersive interaction challenges, with practical recommendations for developers, platform vendors, and researchers.
Abstract
Multi-user Extended Reality (XR) systems enable transformative shared experiences but introduce unique software defects that compromise user experience. Understanding software defects in multi-user XR systems is crucial for enhancing system reliability, yet remains underexplored. To fill the gap, this paper presents the first large-scale empirical study of multi-user XR defects, analyzing 2,649 real-world bug reports from diverse sources, including developer forums, GitHub repositories, and app reviews on mainstream XR app stores. Through rigorous qualitative analysis using iterative open coding, we develop a comprehensive taxonomy that classifies multi-user XR bugs along three dimensions: Symptom Manifestation, Root Cause Origin, and Consequence Severity. Our findings reveal that synchronization inconsistencies and avatar-related anomalies are the most prevalent symptoms, while network/synchronization logic defects and session management flaws emerge as dominant root causes. Critically, over 34% of analyzed bugs lead to severe consequences that fundamentally break the shared experience, including system crashes, persistent disconnections, and complete interaction breakdowns, etc. We also identify concerning privacy and health implications unique to multi-user XR contexts. Based on our findings of defect analysis, we provide actionable recommendations for developers, platform vendors, and researchers. Our results demonstrate that multi-user XR systems face distinct challenges at the intersection of distributed systems, real-time 3D interaction, and immersive experiences, necessitating specialized approaches to testing, debugging, and quality assurance.