Long ago, I used to work at some bank, where SVN branch merging was always super painful and instead of solving people problem, there was holy, e-mail based system running on our common dev machines.

After recieving properly formatted email, script was executed to apply git merge between svn branches. In case of merge issues, the email was sent back with feedback. If everything was okay, a proper sign-off blessing by one of the technopriests as late check was applied and merge concluded.