Any() not searching in locals in debugger environment

Core Development
1

Hello!

I don’t understand if this is a bug, a feature, or me just misunderstanding something:

(Pdb) pp excluded_nodes
{PosixPath('/tmp/pytest-of-facundo/pytest-7/test_copyproject_deeptree0/src/dir1/secret1'),
 PosixPath('/tmp/pytest-of-facundo/pytest-7/test_copyproject_deeptree0/src/dir2/cache'),
 PosixPath('/tmp/pytest-of-facundo/pytest-7/test_copyproject_deeptree0/src/dir2/secret2.txt')}
(Pdb) pp any(parent in excluded_nodes for parent in src_node.parents)
*** NameError: name 'excluded_nodes' is not defined
(Pdb) pp "excluded_nodes" in locals()
True

Why excluded_nodes is not found from inside the any() call?

Thanks!

2

How to reproduce?

$ python
Python 3.11.2 (main, Feb  8 2023, 00:00:00) [GCC 12.2.1 20221121 (Red Hat 12.2.1-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> def f():
...     lst = [1, 2, 3]
...     breakpoint()
... 
>>> f()
--Return--
> <stdin>(3)f()->None
(Pdb) pp lst
[1, 2, 3]
(Pdb) pp any(x == 2 for x in lst)
True
(Pdb) pp "lst" in locals()
True
3

It’s because you are using a generator expression inside the any() call, and genexps and comprehensions are compiled as nested functions. More details at list comprehensions don't see local variables in pdb in python3 · Issue #65360 · python/cpython · GitHub

PEP 709 would fix this for list/dict/set comprehensions, and potentially in the future for non-escaping genexps (as in your example) too.

1 Like
4

To reproduce, you need to reference the outer variable in the value or if clause of the comprehension, not just as the iterated sequence.

5

Awesome, thanks! Subscribed to that bug.

6

:man_facepalming: Sorry for not seeing the obvious.