"Code review" (aka "peer review") seems like a really great idea, so my team started practicing it.
For a little while it worked well, but then a co-worker merged a branch in, and asked for a review of the code. When I went to review her code, the Github diff page was about 420k pixels in height. Given that my screen is about 500px, that works out to 840 screens worth of code to review.
To read the code, fully "grok" it, and write appropriate comments, I probably need an average of one minute per screen, which works out to 14 hours. Now to be fair, some libraries got checked in to this commit, so some portion of that can be skipped ... but even if libraries took up 6 hours worth, that still leaves me with an entire day spent reviewing this merge.
That can't be the most effective use of my time. And this is just one merge; we will no doubt have other large merges to review in the future as well.
So, my question is, what can I do (either in terms of procedure or in terms of utilizing review tools) to let our team have code reviews of branch merges, while at the same time not eating up entire days on reviews?