I have rather big git branch with code that was created on may of this year and never before was merged with master. Compare shows huuuge difference between branch and master: about 50 new files and about 150 modified files. I'm really worried about forthcoming merge.
What can you recommend? Any advises about how better to merge etc.? Have you ever met similar situation? Any, absolutely any notices and advises are highly appreciated.
PS: Repository is under git. The most important parts of project are covered with unit tests. I'm using IDE by JetBrains (if it is important).