Yes, what I mean is, if you're doing code review then there's virtually no additional cost - you're looking over the changes anyway. It doesn't matter that the process is manual if you're already doing it. If you're not doing code review, then you perhaps either have some organisational issues or you have coworkers who are sufficiently responsible that you can trust them to do basic code hygiene work like keeping comments up to date.
I think comments would be more difficult to review than code, since you'd have to carefully make sure they are meaningful by examining the code, without the context of the programmers involved. Alternatively, you could add comments during code review to document the review and basically redo the comments on each review...maybe.
Comments also break flow and get in the way of code reading, but could probably just be hidden during review.
> I think comments would be more difficult to review than code, since you'd have to carefully make sure they are meaningful by examining the code, without the context of the programmers involved.
Actually, that only makes them hard to review if you are trying too hard, which defeats the purpose of reviewing comments -- if it is hard to validate the utility of a comment without the context of the programmer involved, its a bad comment and needs, at a minimum, to be clarified.
After all, the whole point of a comment is to communicate information to a future person who lacks the context of the programmer involved.
