2026-10-05T21:32:31Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:27994 2026-10-05T06:44:03Z ddc:004 open_access

How Developers Use Relation Chains in Gerrit-Based Review Ecosystems: An Empirical Study Across Three Open-Source Ecosystems Belhouchette, Ahmed Chouchen, Moataz Chaieb, Marouene Hamdaqa, Mohammad Hamou-Lhadj, Abdelwahab Code review relation chains stacked changes dependent patches empirical software engineering Gerrit Background. Developers increasingly coordinate dependent review workflows by submitting sequences of related changes rather than monolithic ones. In Gerrit, these dependencies form relation chains: structured review units that link changes together. As chains become more common, they shape review activities through synchronization overhead, CI amplification, and merge-ordering constraints. Aim. We investigate how developers adopt relation chains and how these dependency structures influence review dynamics and outcomes. Method. We analyze 29,580 relation chains from 15 repositories across three Gerrit ecosystems (OpenStack, Wikimedia, ONAP), comprising 401,256 changes, using Mann-Kendall trend tests, Mann-Whitney with Cliff’s δ for chain-vs-solo comparison, and Spearman correlations for base-descendant dependency. Results. Chain prevalence ranges from 5% to 49% across projects, increasing in 14 of 15. Chain changes take a median of 2.6× longer to merge than size-matched solo changes, with the gap widening for very large changes. Review effort propagates through dependency-linked review workflows: base-change review activity co-varies with descendant review activity (ρ = 0.43-0.61 in 14-15/15 projects), and 33.5% of chain members undergo structural evolution during review. Conclusions. Relation chains operate as durable, ecosystem-shaped coordination units with internal structure that change-centric analyses cannot capture. Future review analytics, reviewer-assignment systems, and AI-assisted review tools should reason over chains rather than isolated changes. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Ahmed Belhouchette and Moataz Chouchen and Marouene Chaieb and Mohammad Hamdaqa and Abdelwahab Hamou-Lhadj 2026 Is Part Of LIPIcs, Volume 394, 20th International Symposium on Empirical Software Engineering and Measurement (ESEM 2026) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.ESEM.2026.26 urn:nbn:de:0030-drops-279942 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESEM.2026.26 eng https://creativecommons.org/licenses/by/4.0/legalcode