Join us to discuss learning git on Monday 5th October at 2pm

The use of git is widespread in software engineering, however many novices struggle to get to grips with its complex distributed information model, challenging command line syntax and leaky abstractions. To investigate these pitfalls, we’ll be talking about a paper published by Santiago Perez De Rosso and Daniel Jackson on Purposes, Concepts, Misfits, and a Redesign of Git at OOPSLA. [1] From the abstract:

Git is a widely used version control system that is powerful but complicated. Its complexity may not be an inevitable consequence of its power but rather evidence of flaws in its design. To explore this hypothesis, we analysed the design of Git using a theory that identifies concepts, purposes, and misfits. Some well-known difficulties with Git are described, and explained as misfits in which underlying concepts fail to meet their intended purpose. Based on this analysis, we designed a reworking of Git (called Gitless) that attempts to remedy these flaws.

To correlate misfits with issues reported by users, we conducted a study of Stack Overflow questions. And to determine whether users experienced fewer complications using Gitless in place of Git, we conducted a small user study. Results suggest our approach can be profitable in identifying, analysing, and fixing design problems.

So what’s wrong with git?

Santiago’s presentation on What’s Wrong With Git? at Git Merge in 2017

Details of the zoom meeting have been posted on our slack workspace, see for further information. Thanks to Juha Sorva at Aalto University for recommending this paper.

Journal club dates for your diary

We’ll be meeting on the first Monday of every month throughout autumn, so if you’d like to join us next month or a subsequent month, add these journal club dates to your diary:

  • Monday 5th October at 2pm
  • Monday 2nd November at 2pm
  • Monday 7th December at 2pm


  1. Santiago Perez De Rosso and Daniel Jackson (2016) Purposes, Concepts, Misfits, and a Redesign of Git in Proceedings of the 2016 ACM SIGPLAN International Conference on Object-Oriented Programming, Systems, Languages, and Applications, (OOPSLA), pages 292–310 DOI: 10.1145/2983990.2984018

Join us to discuss student misconceptions in programming, March 23rd from 1pm to 2pm

The Scream by Edvard Munch 😱, reproduced in LEGO by Nathan Sawaya, the

Join us to discuss Identifying Student Misconceptions of Programming by Lisa Kaczmarczyk et al [1] which was voted a top paper from the last 50 years by SIGCSE members in 2019. Here is a summary:

Computing educators are often baffled by the misconceptions that their CS1 students hold. We need to understand these misconceptions more clearly in order to help students form correct conceptions. This paper describes one stage in the development of a concept inventory for Computing Fundamentals: investigation of student misconceptions in a series of core CS1 topics previously identified as both important and difficult. Formal interviews with students revealed four distinct themes, each containing many interesting misconceptions. Three of those misconceptions are detailed in this paper: two misconceptions about memory models, and data assignment when primitives are declared. Individual misconceptions are related, but vary widely, thus providing excellent material to use in the development of the CI. In addition, CS1 instructors are provided immediate usable material for helping their students understand some difficult introductory concepts.

In case you’re wondering, CS1 refers to the first course in the introductory sequence of a computer science major (in American parlance), roughly equivalent to first year undergraduate in the UK. CI refers to a Concept Inventory, a test designed to tell teachers exactly what students know and don’t know. According to Reinventing Nerds, the paper has been influential because it was the “first to apply rigorous research methods to investigating misconceptions”.


  1. Kaczmarczyk, Lisa C.; Petrick, Elizabeth R.; East, J. Philip; Herman, Geoffrey L. (2010). Identifying student misconceptions of programmingSIGCSE ’10: Proceedings of the 41st ACM technical symposium on Computer science education, pages 107–111. doi:10.1145/1734263.1734299