[Everlag]

> The way code review is done: by looking on an output of diff command, pretty-printed in a web-browser, and pointing out obvious mistakes is very inefficient and fundamentally insufficient

> open in IDE/text editor of their choice with or along diff viewer, jump around the new code, run tests and even write some new ones, toy with it

This doesn't scale. I know team leads in large projects where reviewing external contributions is their main responsibility; this style would be impossible.

Instead, I think the human, diff based approach with CI running against the reviewed code is enough. A reviewer going over the tests which are shown to be passing should be sufficient after the usual diff read-through.