you can repair,
i did, all you need is a blow torch, preferably and fine flame, first, compress the pipe back together as best you can, i imagine it happened on the outer end of the u bend, empty all water out or it wont get hot enough,
scrape away the soldier on it already until you get to the copper, heat the pipe up and then work the soldier onto it in stages, make it nice and thick,
thats what i did with mine