I get stack overflows all the way back to 3.7, so it's probably not anything new. But our stack overflow detection is clearly not going to catch this case. It's really only set up for a direct call within Python code, but this is going through many more steps.

Best thing you can do as a user is run it with "python -X faulthandler ..." to see the error. Perhaps we can handle the stack overflow ourselves and print a message suggesting that option, but unfortunately this problem doesn't have a generic solution :( The assumption is that you have a known recursion limit for your application, and as a scripting engine, we don't. Decoupling from the C stack is the best hope.