As a maintainer of small project I would say that it depends. If the code is really useful and contributor is not willing to fix any of my comments, I would mer

As a maintainer of small project I would say that it depends. If the code is really useful and contributor is not willing to fix any of my comments, I would merge it anyway and fix it myself. If the code is so bad that it would be easier for me to completely re-write it myself, I would reject it. I'd like to think that my code review comments are reasonable most of the time, so it doesn't usually take more than 2 or 3 iterations to complete a pull request.