[devanl]

In my mind at least, the issue with relying on on ownership, especially in a smaller team with limited resources, is that the owner isn't just the person who authoritatively understands that subsystem. The owner ends up being assigned _all_ of the work on that subsystem because it's "their responsibility".

As a result, any work that's assigned to someone else will only interact with at the interfaces / boundaries. And of course, that's sort of the intention with modularity / loose coupling - it's not necessary to learn the gory details of the XYZ subsystem's implementation, only its API. Knowing the details is certainly valuable, but there's no baseline impetus to get the owner to explain the details.

Taking over from someone who's ceding responsibility, but staying at the company, I agree that's manageable. But sometimes people get laid off suddenly (or perhaps get hit by a bus, etc) and there's no chance to get the one person who has it all in their head to explain it to you.

You mentioned high turnover, but if anything, a place with high turnover has less information locked up in a single person's head. If Alice who's worked at the company for 25 years and has always owned the code leaves, you're going to have a much harder time getting all of the tribal knowledge out of her head on two weeks notice compared to Bob who only made it 6 months.

To me, the value of code review is that even at its worst, someone other than the author is forced to look at the code. No process can force a reviewer to take an active interest in a particular subsystem, but at least we can make them look at pieces of it and see if it gets them curious enough to ask further questions of the author and better understand the system.

For myself, knowing that someone else will have to understand my code, even through the limited lens of a code review, makes me more diligent about making sure that the code is clean and the pull request has enough context that someone playing code archeologist will be able to make sense of it, even if I'm not walking them through it in real time. I will admit that this is not a universal thing - I've worked with coworkers where no matter what process is in place, they won't do the basic courtesy of reading their own changelists to see that they accidentally committed random junk files from their local machine.

I agree that good documentation around requirements is valuable. I find pull requests / code reviews are a great opportunity to highlight how the code relates to specific requirements, since the focus is narrower.