> Optimizing for the common scenario means giving developers primary ownership of portions of the code base and not allowing other developers to change that code without approval from the primary owner. This results in higher productivity since any given developer is more likely to be familiar with the code in which they will typically be working.
I have worked with someone overly protective of the code sector he wrote, but it has caused problems since I would like to fix some bugs in the API signature of that code, but the developer has stonewalled me in the past & raised a ruckus when I filed PRs to fix some of it. If it is something that affects how other people interface with a feature, IMO it is not a good thing to necessarily designate a primary owner & mandate all changes go through him/her. Granted, some of the problem is that the other developer probably was in the wrong being obstinate, but you work with the cards you're given.