What is the git command return code when you execute the same from the command line? i.e. If linux or mac run the command from the command line then echo $? which will show you the return code. You'll have to google how to do the same on Windows if you're using Windows.

If git's return code is indeed zero on a conflict, you'll have to parse the output of the git command to determine success/failure, but I know that git generally sets return code 1 on error, 0 on success, although there may be exceptions to that rule.