Yeah, I'm familiar with PS1, but I was a bit surprised to learn that simple things that a PS1 script might do (git status, perhaps) are attack vectors. It seems that one big concern is the core.fsmonitor option (which I just learned about now). From the git-config man page:
> If set, the value of this variable is used as a command which will identify all files that may have changed since the requested date/time.