Comment by threatofrain
14 hours ago
Let's say a teammate is writing code to do geometric projection of streets and roads onto live video. Another teammate is writing code to do automated drone pursuit of cars. Let's say I'm over here writing auth code, making sure I'm modeling all the branches which might occur in some order.
To what degree do we expect intellectual peerage from someone just glancing into this problem because of a PR? I would expect that to be the proper intellectual peer of someone studying the problem, it's quite reasonable to basically double your efforts.
If the team is that small and working on things that are that disparate, then it is also very vulnerable to one of those people leaving, at which point there's a whole part of the project that nobody on the team has a good understanding of.
Having somebody else devote enough time to being up to speed enough to do code review on an area is also an investment in resilience so the team isn't suddenly in huge difficulty if the lone expert in that area leaves. It's still a problem, but at least you have one other person who's been looking at the code and talking about it with the now-departed expert, instead of nobody.
This is an unusually low overlap per topic; probably needs a different structure to traditional prs to get the best chance to benefit from more eyes... Higher scope planning or something like longer but intermittent partner programming.
Generally if the reviewer is not familiar with the content asynchronous line by line reviews are of limited value.