test_helpers.py

# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
# For details: https://github.com/pylint-dev/astroid/blob/main/LICENSE
# Copyright (c) https://github.com/pylint-dev/astroid/blob/main/CONTRIBUTORS.txt

import builtins
import unittest

import pytest

from astroid import builder, helpers, manager, nodes, raw_building, util
from astroid.const import IS_PYPY
from astroid.exceptions import _NonDeducibleTypeHierarchy
from astroid.nodes.scoped_nodes import ClassDef


class TestHelpers(unittest.TestCase):
    def setUp(self) -> None:
        builtins_name = builtins.__name__
        astroid_manager = manager.AstroidManager()
        self.builtins = astroid_manager.astroid_cache[builtins_name]
        self.manager = manager.AstroidManager()

    def _extract(self, obj_name: str) -> ClassDef:
        return self.builtins.getattr(obj_name)[0]

    def _build_custom_builtin(self, obj_name: str) -> ClassDef:
        proxy = raw_building.build_class(obj_name)
        proxy.parent = self.builtins
        return proxy

    def assert_classes_equal(self, cls: ClassDef, other: ClassDef) -> None:
        self.assertEqual(cls.name, other.name)
        self.assertEqual(cls.parent, other.parent)
        self.assertEqual(cls.qname(), other.qname())

    def test_object_type(self) -> None:
        pairs = [
            ("1", self._extract("int")),
            ("[]", self._extract("list")),
            ("{1, 2, 3}", self._extract("set")),
            ("{1:2, 4:3}", self._extract("dict")),
            ("type", self._extract("type")),
            ("object", self._extract("type")),
            ("object()", self._extract("object")),
            ("super()", self._extract("super")),
            ("lambda: None", self._build_custom_builtin("function")),
            ("len", self._build_custom_builtin("builtin_function_or_method")),
            ("None", self._build_custom_builtin("NoneType")),
            ("import sys\nsys#@", self._build_custom_builtin("module")),
        ]
        for code, expected in pairs:
            node = builder.extract_node(code)
            objtype = helpers.object_type(node)
            self.assert_classes_equal(objtype, expected)

    def test_object_type_classes_and_functions(self) -> None:
        ast_nodes = builder.extract_node(
            """
        def generator():
            yield

        class A(object):
            def test(self):
                self #@
            @classmethod
            def cls_method(cls): pass
            @staticmethod
            def static_method(): pass
        A #@
        A() #@
        A.test #@
        A().test #@
        A.cls_method #@
        A().cls_method #@
        A.static_method #@
        A().static_method #@
        generator() #@
        """
        )
        assert isinstance(ast_nodes, list)
        from_self = helpers.object_type(ast_nodes[0])
        cls = next(ast_nodes[1].infer())
        self.assert_classes_equal(from_self, cls)

        cls_type = helpers.object_type(ast_nodes[1])
        self.assert_classes_equal(cls_type, self._extract("type"))

        instance_type = helpers.object_type(ast_nodes[2])
        cls = next(ast_nodes[2].infer())._proxied
        self.assert_classes_equal(instance_type, cls)

        expected_method_types = [
            (ast_nodes[3], "function"),
            (ast_nodes[4], "method"),
            (ast_nodes[5], "method"),
            (ast_nodes[6], "method"),
            (ast_nodes[7], "function"),
            (ast_nodes[8], "function"),
            (ast_nodes[9], "generator"),
        ]
        for node, expected in expected_method_types:
            node_type = helpers.object_type(node)
            expected_type = self._build_custom_builtin(expected)
            self.assert_classes_equal(node_type, expected_type)

    def test_object_type_metaclasses(self) -> None:
        module = builder.parse(
            """
        import abc
        class Meta(metaclass=abc.ABCMeta):
            pass
        meta_instance = Meta()
        """
        )
        meta_type = helpers.object_type(module["Meta"])
        self.assert_classes_equal(meta_type, module["Meta"].metaclass())

        meta_instance = next(module["meta_instance"].infer())
        instance_type = helpers.object_type(meta_instance)
        self.assert_classes_equal(instance_type, module["Meta"])

    def test_object_type_most_derived(self) -> None:
        node = builder.extract_node(
            """
        class A(type):
            def __new__(*args, **kwargs):
                 return type.__new__(*args, **kwargs)
        class B(object): pass
        class C(object, metaclass=A): pass

        # The most derived metaclass of D is A rather than type.
        class D(B , C): #@
            pass
        """
        )
        assert isinstance(node, nodes.NodeNG)
        metaclass = node.metaclass()
        self.assertEqual(metaclass.name, "A")
        obj_type = helpers.object_type(node)
        self.assertEqual(metaclass, obj_type)

    def test_inference_errors(self) -> None:
        node = builder.extract_node(
            """
        from unknown import Unknown
        u = Unknown #@
        """
        )
        self.assertEqual(helpers.object_type(node), util.Uninferable)

    @pytest.mark.skipif(IS_PYPY, reason="__code__ will not be Unknown on PyPy")
    def test_inference_errors_2(self) -> None:
        node = builder.extract_node("type(float.__new__.__code__)")
        self.assertIs(helpers.object_type(node), util.Uninferable)

    def test_object_type_too_many_types(self) -> None:
        node = builder.extract_node(
            """
        from unknown import Unknown
        def test(x):
            if x:
                return lambda: None
            else:
                return 1
        test(Unknown) #@
        """
        )
        self.assertEqual(helpers.object_type(node), util.Uninferable)

    def test_is_subtype(self) -> None:
        ast_nodes = builder.extract_node(
            """
        class int_subclass(int):
            pass
        class A(object): pass #@
        class B(A): pass #@
        class C(A): pass #@
        int_subclass() #@
        """
        )
        assert isinstance(ast_nodes, list)
        cls_a = ast_nodes[0]
        cls_b = ast_nodes[1]
        cls_c = ast_nodes[2]
        int_subclass = ast_nodes[3]
        int_subclass = helpers.object_type(next(int_subclass.infer()))
        base_int = self._extract("int")
        self.assertTrue(helpers.is_subtype(int_subclass, base_int))
        self.assertTrue(helpers.is_supertype(base_int, int_subclass))

        self.assertTrue(helpers.is_supertype(cls_a, cls_b))
        self.assertTrue(helpers.is_supertype(cls_a, cls_c))
        self.assertTrue(helpers.is_subtype(cls_b, cls_a))
        self.assertTrue(helpers.is_subtype(cls_c, cls_a))
        self.assertFalse(helpers.is_subtype(cls_a, cls_b))
        self.assertFalse(helpers.is_subtype(cls_a, cls_b))

    def test_is_subtype_supertype_mro_error(self) -> None:
        cls_e, cls_f = builder.extract_node(
            """
        class A(object): pass
        class B(A): pass
        class C(A): pass
        class D(B, C): pass
        class E(C, B): pass #@
        class F(D, E): pass #@
        """
        )
        self.assertFalse(helpers.is_subtype(cls_e, cls_f))

        self.assertFalse(helpers.is_subtype(cls_e, cls_f))
        with self.assertRaises(_NonDeducibleTypeHierarchy):
            helpers.is_subtype(cls_f, cls_e)
        self.assertFalse(helpers.is_supertype(cls_f, cls_e))

    def test_is_subtype_supertype_unknown_bases(self) -> None:
        cls_a, cls_b = builder.extract_node(
            """
        from unknown import Unknown
        class A(Unknown): pass #@
        class B(A): pass #@
        """
        )
        with self.assertRaises(_NonDeducibleTypeHierarchy):
            helpers.is_subtype(cls_a, cls_b)
        with self.assertRaises(_NonDeducibleTypeHierarchy):
            helpers.is_supertype(cls_a, cls_b)

    def test_is_subtype_supertype_unrelated_classes(self) -> None:
        cls_a, cls_b = builder.extract_node(
            """
        class A(object): pass #@
        class B(object): pass #@
        """
        )
        self.assertFalse(helpers.is_subtype(cls_a, cls_b))
        self.assertFalse(helpers.is_subtype(cls_b, cls_a))
        self.assertFalse(helpers.is_supertype(cls_a, cls_b))
        self.assertFalse(helpers.is_supertype(cls_b, cls_a))

    def test_is_subtype_supertype_classes_no_type_ancestor(self) -> None:
        cls_a = builder.extract_node(
            """
        class A(object): #@
            pass
        """
        )
        builtin_type = self._extract("type")
        self.assertFalse(helpers.is_supertype(builtin_type, cls_a))
        self.assertFalse(helpers.is_subtype(cls_a, builtin_type))

    def test_is_subtype_supertype_classes_metaclasses(self) -> None:
        cls_a = builder.extract_node(
            """
        class A(type): #@
            pass
        """
        )
        builtin_type = self._extract("type")
        self.assertTrue(helpers.is_supertype(builtin_type, cls_a))
        self.assertTrue(helpers.is_subtype(cls_a, builtin_type))


def test_uninferable_for_safe_infer() -> None:
    uninfer = util.Uninferable
    assert util.safe_infer(util.Uninferable) == uninfer


def test_safe_infer_shim() -> None:
    with pytest.warns(DeprecationWarning) as records:
        helpers.safe_infer(nodes.Unknown())

    assert (
        "Import safe_infer from astroid.util; this shim in astroid.helpers will be removed."
        in records[0].message.args[0]
    )