Boundary Spanners in Open Source Software Development: A Study of Python Email Archives

Abstract

A sound Decision-Making (DM) process is key to the successful governance of software projects. In many Open Source Software Development (OSSD) communities, DM processes lie buried amongst vast amounts of publicly available data. Hidden within this data lie the rationale for decisions that led to the evolution and maintenance of software products. While there have been some efforts to extract DM processes from publicly available data, the rationale behind 'how' the decisions are made have seldom been explored. Extracting the rationale for these decisions can facilitate transparency (by making them known), and also promote accountability on the part of decisionmakers. This work bridges this gap by means of a large-scale study that unearths the rationale behind decisions from Python development email archives comprising about 1.5 million emails. This paper makes two main contributions. First, it makes a knowledge contribution by unearthing and presenting the rationale behind decisions made. Second, it makes a methodological contribution by presenting a heuristics-based rationale extraction system called Rationale Miner that employs multiple heuristics, and follows a data-driven, bottom-up approach to infer the rationale behind specific decisions (e.g., whether a new module is implemented based on core developer consensus or benevolent dictator's pronouncement). Our approach can be applied to extract rationale in other OSSD communities that have similar governance structures.

Influence of Roles in Decision-Making during OSS Development — A Study of Python

“…Members are filtered by those having the highest betweenness centrality. Most of the members in both diagrams are Python core developers who have been BDFL Delegates for PEPs as previously reported in [39]. The diagram on the right shows the BDFL Delegates both as a collective node and individual nodes.…”

“…From 2014 [60], Python packaging-related PEPs were discussed here to fast-track decisions and Nick Coghlan (PEP editor from 2012) decided most of these. [39]. Full email contribution data for all 466 PEPs decided either by the BDFL or a BDFL Delegate and further separation of these contributions by PEP type are available online 3 .…”

“…The BDFL had the second highest values in the first case, but in the second case, the Delegates and three members had higher values than the BDFL. Of these three members, Nick Coghlan has [39]. Thus, their prominence in these SNA metrics could be attributed to them having high involvement when making decisions.…”

“…To evaluate the correctness of our results (i.e., that the identified rationale is correct), we presented our findings to a prominent Python core developer (name withheld) who had been the lead author or co-author of 22 PEPs, had been BDFL Delegate 14 times [39], and was a former Python Steering Council member. He replied "I think your list of reasons looks good".…”

“…shows the top three Python roles (authors, BDFL and BDFL delegates) and the eight members who are prominent in Python DM discussions for the 415 PEPs decided by the BDFL. All eight members are Python core developers[39,56]. For comparison, we also have included (in italics) the contributions of BDFL, PEP authors and the top two members (Brett Cannon and Nick Coghlan) in the 51 PEPs where the BDFL Delegates made the decisions.…”