False positive used-before-assignment for filtered comprehensions in try blocks

[jacobtylerwalls]

Bug description

def func():
    try:
        print(value for value in range(1 / 0) if isinstance(value, int))  # BUG: emits used-before-assignment
    except ZeroDivisionError:
        value = 1

Configuration

No response

Command used

pylint a.py

Pylint output

************* Module a
/Users/.../a.py:3:60: E0601: Using variable 'value' before assignment (used-before-assignment)

Expected behavior

No message.

Here, found_nodes for the node inside the generator expression includes the assignment of value in the except block.
https://github.com/PyCQA/pylint/blob/c0fbbb7adbc39cbd67bbd0e0b1ca4e9421c12643/pylint/checkers/variables.py#L611-L620

I'm not sure if the responsibility for filtering that out lies in to_consume(); if not, I suppose the new used-before-assignment logic will have to deal with it.

Pylint version

Caused in bd55b27d41542e3ca1f031f986b6151f6cac457f (2.13.0 unreleased)

OS / Environment

No response

Additional dependencies

No response

[DanielNoord]

@jacobtylerwalls This is one of the final issues in 2.13 without an associated PR. Would you consider taking a look at it before we release it? Feel free to say no obviously, I'm just going through any remaining open issues and PRs 😉

[jacobtylerwalls]

I'll let you know this week if I think I can. Meanwhile, I was wondering if you had a gut feeling about this part without having to do much investigation straight away:

I'm not sure if the responsibility for filtering that out lies in to_consume()

And if so, is that in astroid? Or other related issues you know of with comprehension variables not being isolated enough by the variables checker?

[DanielNoord]

I'll let you know this week if I think I can.

Thanks!

Meanwhile, I was wondering if you had a gut feeling about this part without having to do much investigation straight away:

I'm not sure if the responsibility for filtering that out lies in to_consume()

And if so, is that in astroid? Or other related issues you know of with comprehension variables not being isolated enough by the variables checker?

diff --git a/pylint/checkers/variables.py b/pylint/checkers/variables.py
index 66af3ec94..db9c812a7 100644
--- a/pylint/checkers/variables.py
+++ b/pylint/checkers/variables.py
@@ -1316,6 +1316,7 @@ class VariablesChecker(BaseChecker):
             if utils.is_func_decorator(current_consumer.node) or not (
                 current_consumer.scope_type == "comprehension"
                 and self._has_homonym_in_upper_function_scope(node, consumer_level)
+                and not node.parent in node.parent.parent.ifs
             ):
                 self._check_late_binding_closure(node)
                 self._loopvar_name(node)

This raise unused-variable but I think could be a start. A little investigation showed that we do check the comprehension scope for a value name but we don't seem to find it. Then we move up to function and see that is defined after we try and access it.
The fix should thus probably be in _check_consumer and how it handles the ifs of comprehensions.