An example of a try/except where pylint does not detect UnboundLocalError (used-before-assignment)

[markmark206]

Bug description

This is related to (but not exactly duplicated by) what is described in #4913 and #4045 .

Here is an example where a variable is initialized inside a try block, and is used in the except, before it had a chance to be initialized.

$ cat use_before_assignment.py

def compute() -> int:
    raise ValueError("bad chickens")

def count_chickens():
    try:
        chicken_count = compute()
    except ValueError:
        print(chicken_count)

count_chickens()

if i run this code, i get an error -- as i would expect.

$ python use_before_assignment.py
Traceback (most recent call last):
  File "/Users/markgenba/src/genba/use_before_assignment.py", line 6, in count_chickens
    chicken_count = compute()
  File "/Users/markgenba/src/genba/use_before_assignment.py", line 2, in compute
    raise ValueError("bad chickens")
ValueError: bad chickens

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/markgenba/src/genba/use_before_assignment.py", line 10, in <module>
    count_chickens()
  File "/Users/markgenba/src/genba/use_before_assignment.py", line 8, in count_chickens
    print(chicken_count)
UnboundLocalError: local variable 'chicken_count' referenced before assignment

however, pylint doesn't see a problem with the code:

$ pylint -d missing-module-docstring,missing-function-docstring use_before_assignment.py

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

Configuration

No response

Command used

pylint -d missing-module-docstring,missing-function-docstring use_before_assignment.py

Pylint output

--------------------------------------------------------------------
Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

Expected behavior

I would expect pylint to report used-before-assignment in the line in the except block where we use the variable that was never initialized:

        print(chicken_count)

Pylint version

pylint 2.12.2
astroid 2.9.3
Python 3.9.9 (v3.9.9:ccb0e6a345, Nov 15 2021, 13:06:05)
[Clang 13.0.0 (clang-1300.0.29.3)]

OS / Environment

Mac OS Monteray 12.2 (21D49)

Additional dependencies

No response

[markmark206]

it looks like this issue has already been fixed: #4045 (comment) closing. thank you!!