>> There are lots of ways to provide feedback. I suggest stating the problem with the code and providing a solution. If that's the only possible solution to get past your review, state and don't ask. You can also give a carrot with "do this and I'll approve the merge."
Yes. This. Clarity is a prerequisite for tact.
Also, be consistent in your tone and style across reviews in a given project or org -- no matter who you're talking to. For instance, on one development project I was informed that all new tickets should use the language "shall" instead of "should" or "will." Consistent language gives everyone a common reference point and helps keep people from feeling "singled out."
Yes. This. Clarity is a prerequisite for tact.
Also, be consistent in your tone and style across reviews in a given project or org -- no matter who you're talking to. For instance, on one development project I was informed that all new tickets should use the language "shall" instead of "should" or "will." Consistent language gives everyone a common reference point and helps keep people from feeling "singled out."