I upgraded to IDEA 13, and the following code in my build file stopped working (just to get the hash of the current git head for some logging):
def hashProc = "git rev-parse HEAD".execute();
def code = hashProc.waitFor();
def hash = hashProc.in.text
This was running fine in IDEA 12, and runs fine from the command line. In 13, the 'code' is 128. I guessed that there was a path problem, but using a full path to the git executable did not solve the problem.