If the leak was at the old 45 degree fitting, there is no easy way to fix it cleanly. You have to cut one pipe back, and then a new 45 won't line up with the other pipe. The existing repair is what follows from someone with less experience dealing with that issue.
The correct way to fix it is by cutting both pipes back further (instead of just one) and using two slip fittings to get the new 45 in the same place as the old. Doing that requires some more digging, rather exact measurements/cutting, three or four hands, and will be tricky to get installed without any flex to get things into place, but will make a better repair.