Find exception names in a Python module

listexn-raised.py

#!/usr/bin/env python

import compiler.ast
import compiler.visitor as visitor

__author__ = 'Sarah Mount <s.mount@wlv.ac.uk>'
__date__ = 'May 2010'


class ExceptionFinder(visitor.ASTVisitor):
    """List all exceptions raised by a module.
    """

    def __init__(self, filename):
        visitor.ASTVisitor.__init__(self)
        self.filename = filename
        self.exns = set()
        return

    def __visitName(self, node):
        """Should not be called by generic visit, otherwise every name
        will be reported as an exception type.
        """
        self.exns.add(node.name)
        return
        
    def __visitCallFunc(self, node):
        """Should not be called by generic visit, otherwise every name
        will be reported as an exception type.
        """
        self.__visitName(node.node)
        return
        
    def visitRaise(self, node):
        """Visit a raise statement.
        Cheat the default dispatcher.
        """
        if isinstance(node.expr1, compiler.ast.Name):
            self.__visitName(node.expr1)
        elif isinstance(node.expr1, compiler.ast.CallFunc):
            self.__visitCallFunc(node.expr1)
        return


if __name__ == '__main__':
    import sys
    if len(sys.argv) <= 1:
        print 'Give me a file name!'
    print 'Looking for exception types in: %s' % sys.argv[1]

    lint = ExceptionFinder(sys.argv[1])
    compiler.walk(compiler.parseFile(sys.argv[1]),
                  lint,
                  walker=lint,
                  verbose=5)
    for exn in lint.exns:
        print '%s:%s is an exception type' % (sys.argv[1], exn)

@snim2 Is there a way to only call and parse a single function from a module?

like:

from http.client import HTTPConnection

compiler.walk(HTTPConnection.get_response)

This was written for Python2.7 BTW, so you would need to adapt it a bit for Python3, but I think you can do something like this:

$ python3
Python 3.8.10 (default, Jun 22 2022, 20:18:18) 
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ast
>>> from http.client import HTTPConnection
>>> ast.walk(HTTPConnection.getresponse)
<generator object walk at 0x7ff58eff0c80>
>>> 

@snim2 Thanks for the reply. This seems so much harder then I expected. It seems by default the AST only parses what it sees. It doesn't drill down into other function calls.

I'm trying to walk all code that might be called. Like both sides of an if statement. To record what exceptions might be raised from a given starting point.

Take this example

def raise_a():
    raise Exception('testing')

def raise_b():
    raise TypeError()

def test_raise():
    raise_a()
    raise_b()
    raise ValueError()

If I walk test_raise then I see the calls to raise_a() and raise_b() but ast.walk does not walk the AST for the raise_a and raise_b.

I have actually found a hacky workaround that does work. But I'm having trouble with my call to HTTPConnection.getresponse.

I cant start a new gist if you are interested in what I am up to.

It's been a very long time since I looked at this code, so I'm not sure that I can be of much help. However, I found this blog post: https://deepsource.io/blog/python-asts-by-building-your-own-linter/ If you haven't seen it before, I think it gives sure a useful introduction to the `ast` module.

…

On Sat, 30 Jul 2022, 19:52 Levi, ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ @snim2 <https://github.com/snim2> Thanks for the reply. This seems so much harder then I expected. It seems by default the AST only parses what it sees. It doesn't drill down into other function calls. I'm trying to walk all code that might be called. Like both sides of an if statement. To record what exceptions might be raised from a given starting point. Take this example def raise_a(): raise Exception('testing') def raise_b(): raise TypeError() def test_raise(): raise_a() raise_b() raise ValueError() If I walk test_raise then I see the calls to raise_a() and raise_b() but ast.walk does not walk the AST for the raise_a and raise_b. I have actually found a hacky workaround that does work. But I'm having trouble with my call to HTTPConnection.getresponse. I cant start a new gist if you are interested in what I am up to. — Reply to this email directly, view it on GitHub <https://gist.github.com/402869#gistcomment-4250515>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAX3CWGE2VJBFXS5DZ2IZDVWV2XLANCNFSM55DNEFWQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

@snim2 The initial release of Deep-AST is out. Thanks for the inspiration, I will make sure I add this gist to the README.