[Python] How to find all exception types at `raise` calls in Python?

I need to collect all possible things a given function explicitly raises using the raise keyword for a source analyzer tool I am working on.

For example:

from some.package import CustomError

class NewException(Exception):...

def something(i):
if i == 2:
raise RuntimeError("This is a runtime error")
else:
raise CustomError("This is a custom error")

try:
something()
except ValueError:
raise
except Exception as e:
raise NewException(e) from e


In the case of this function I would like to get a set of {<class RuntimeError>, <class some.package.CustomError>, <class ValueError>, <class [function_path].NewException>}.

My current (and unfinished) solution is using the ast and inspect module to parse the function's source code into an AST and collect the exceptions there but I am stuck with detecting custom exceptions as the program crashes while evaluating them.

import inspect
import ast

def _analyze_function(function: Callable[..., Any]):
exceptions: set[type[BaseException]] = set()
abstract_syntax_tree = ast.parse(inspect.getsource(function), mode="exec")
for node in ast.walk(abstract_syntax_tree):
if not isinstance(node, ast.Raise):
continue

if node.exc is None:
print("No exception specified")
continue

match type(node.exc):
case ast.Call:
call_result = type(eval(ast.unparse(node.exc)))
if not issubclass(call_result, BaseException):
continue
exceptions.add(call_result)
case _:
pass


A problem with this approach is that there is external code execution which could lead to malicious code being evaluated.

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