[ENH] Debugging - "raise" exception without actually raising an exception (print stack) about cython HOT 1 OPEN

The issue here is that Cython generates the traceback on demand as the exception propagates upwards. So at the point you catch it the only bit of stack trace that exists is for the line where the exception is thrown.

The main reason for that is to reduce overhead in the common (non-exception) case - we really don't want to be spending time tracking the call stack.

If we were to do this, it would probably have to be a compiler directive to turn it on so you'd only be able to get the full trace for functions where this is manually enabled.

I think it'd actually end up being a reasonable performance cost in a lot of cases so we wouldn't want to enable it by default.

from cython.