AstroidError crash on extremely specific enumerate to dictionary comprehension.

[grantthchen]

Bug description

Very new to submitting bugs, and this is really easily circumvented, but the scary error message prompted me to post this in case it's something of use to Pylint developers.

When parsing the following a.py:

xs = [1, 2, 3]
testdict = {j: i for i, j in enumerate(xs, -len(xs))}

Pylint crashes with AstroidError.

The following code works without issues:

xs = [1, 2, 3]
testdict = {j: i for i, j in enumerate([1, 2, 3], -len(xs))}
testdict = {j: i for i, j in enumerate(xs, len(xs))}
s = -len(xs)
testdict = {j: i for i, j in enumerate(xs, s)}
testdict = {j: i for i, j in list(enumerate(xs, -len(xs)))}
testdict = {j: i for i, j in dict(enumerate(xs, -len(xs))).items()}

Configuration

Command used

pylint a.py

Pylint output

pylint crashed with a ``AstroidError`` and with the following stacktrace:

Traceback (most recent call last):
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/lint/pylinter.py", line 789, in _lint_file
    check_astroid_module(module)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/lint/pylinter.py", line 1018, in check_astroid_module
    retval = self._check_astroid_module(
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/lint/pylinter.py", line 1070, in _check_astroid_module
    walker.walk(node)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/utils/ast_walker.py", line 94, in walk
    self.walk(child)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/utils/ast_walker.py", line 91, in walk
    callback(astroid)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/checkers/refactoring/refactoring_checker.py", line 1814, in visit_comprehension
    self._check_unnecessary_list_index_lookup(node)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/checkers/refactoring/refactoring_checker.py", line 2312, in _check_unnecessary_list_index_lookup
    has_start_arg, confidence = self._enumerate_with_start(node)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/checkers/refactoring/refactoring_checker.py", line 2437, in _enumerate_with_start
    start_val, confidence = self._get_start_value(start_arg)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/checkers/refactoring/refactoring_checker.py", line 2463, in _get_start_value
    return node.operand.value, HIGH
AttributeError: 'Call' object has no attribute 'value'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/lint/pylinter.py", line 753, in _lint_files
    self._lint_file(fileitem, module, check_astroid_module)
  File "/home/redacted/.vscode-server/extensions/ms-python.pylint-2024.2.0/bundled/libs/pylint/lint/pylinter.py", line 791, in _lint_file
    raise astroid.AstroidError from e
astroid.exceptions.AstroidError

Expected behavior

No crash.

Pylint version

pylint 3.2.7
astroid 3.2.4
Python 3.8.17 (default, Jul  5 2023, 21:04:15) 
[GCC 11.2.0]

OS / Environment

linux (Linux)

Additional dependencies

[Pierre-Sassoulas]

Thank you for opening the issue with a nice reproducer ! Little by little we're making this check crash free, but I'm pretty sure someone will get even more creative with what can go in enumerate in the future. Might think hard about not letting any assumption about nodes enter the codebase for the next review 😄

[Pierre-Sassoulas]

The fix is going to be released in 3.3.9 "soonish ™️"