Aspiring big firm associates must have infinite patience. Or deep wells of hope. How else to explain why so few of them have taken legal action against firms for reneging on their job offers?

But Sarah Martinez, a 2008 graduate of the law school at the University of California at Davis, seems to have run out of both. She just did the unthinkable: She’s suing San Francisco’s Howard, Rice, Nemerovski, Canady, Falk & Rabkin for rescinding her job offer.