IndexError when calling extract_node

[gabe-sherman]

The execution of the below code results in an exception with the following message: IndexError: list index out of range. This exception occurs in _extract_expressions at line 321 in builder.py.

from astroid.brain.brain_boto3 import extract_node
extract_node("__()")

Version:

v4.0.0.dev1 -- also occurs in v3.3.10

Traceback Report

Traceback (most recent call last):
  File "rep.py", line 2, in <module>
    extract_node("__()")
  File "lib/python3.9/site-packages/astroid/builder.py", line 452, in extract_node
    extracted.extend(_extract_expressions(tree))
  File "ib/python3.9/site-packages/astroid/builder.py", line 340, in _extract_expressions
    yield from _extract_expressions(child)
  File "lib/python3.9/site-packages/astroid/builder.py", line 340, in _extract_expressions
    yield from _extract_expressions(child)
  File "lib/python3.9/site-packages/astroid/builder.py", line 321, in _extract_expressions
    real_expr = node.args[0]
IndexError: list index out of range

[Pierre-Sassoulas]

Nice catch, it seems you hit some internal implementation quirks. Are you using fuzzing 😄 ?

[gabe-sherman]

I sure am, thanks for the quick response!

[Pierre-Sassoulas]

The fix will be released in 3.3.11, probably at the same time than the fix for #2733