Drop support for Python 3.7 (#8609)

* Drop support for Python 3.7
* Update py-version + classifier
* Update functional tests

14 files changed, 15 insertions, 87 deletions

diff --git a/pylint/checkers/__init__.py b/pylint/checkers/__init__.py
index 8af4bae67..0f9985918 100644
--- a/pylint/checkers/__init__.py
+++ b/pylint/checkers/__init__.py
@@ -42,8 +42,7 @@ messages nor reports. XXX not true, emit a 07 report !
 
 from __future__ import annotations
 
-import sys
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Literal
 
 from pylint.checkers.base_checker import (
     BaseChecker,
@@ -53,11 +52,6 @@ from pylint.checkers.base_checker import (
 from pylint.checkers.deprecated import DeprecatedMixin
 from pylint.utils import LinterStats, diff_string, register_plugins
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
diff --git a/pylint/checkers/base/basic_checker.py b/pylint/checkers/base/basic_checker.py
index dd46d8553..627f3c603 100644
--- a/pylint/checkers/base/basic_checker.py
+++ b/pylint/checkers/base/basic_checker.py
@@ -8,9 +8,8 @@ from __future__ import annotations
 
 import collections
 import itertools
-import sys
 from collections.abc import Iterator
-from typing import TYPE_CHECKING, cast
+from typing import TYPE_CHECKING, Literal, cast
 
 import astroid
 from astroid import nodes, objects, util
@@ -24,11 +23,6 @@ from pylint.utils import LinterStats
 if TYPE_CHECKING:
     from pylint.lint.pylinter import PyLinter
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 
 class _BasicChecker(BaseChecker):
     """Permits separating multiple checks with the same checker name into
diff --git a/pylint/checkers/base/docstring_checker.py b/pylint/checkers/base/docstring_checker.py
index 5a681eeb3..91b3e7d4a 100644
--- a/pylint/checkers/base/docstring_checker.py
+++ b/pylint/checkers/base/docstring_checker.py
@@ -7,7 +7,7 @@
 from __future__ import annotations
 
 import re
-import sys
+from typing import Literal
 
 import astroid
 from astroid import nodes
@@ -21,11 +21,6 @@ from pylint.checkers.utils import (
     is_property_setter,
 )
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 # do not require a doc string on private/system methods
 NO_REQUIRED_DOC_RGX = re.compile("^_")
 
diff --git a/pylint/checkers/classes/class_checker.py b/pylint/checkers/classes/class_checker.py
index 9b0bd50b1..77a795bcb 100644
--- a/pylint/checkers/classes/class_checker.py
+++ b/pylint/checkers/classes/class_checker.py
@@ -7,9 +7,9 @@
 from __future__ import annotations
 
 import collections
-import sys
 from collections import defaultdict
 from collections.abc import Callable, Sequence
+from functools import cached_property
 from itertools import chain, zip_longest
 from re import Pattern
 from typing import TYPE_CHECKING, Any, Union
@@ -47,11 +47,6 @@ if TYPE_CHECKING:
     from pylint.lint.pylinter import PyLinter
 
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-else:
-    from astroid.decorators import cachedproperty as cached_property
-
 _AccessNodes = Union[nodes.Attribute, nodes.AssignAttr]
 
 INVALID_BASE_CLASSES = {"bool", "range", "slice", "memoryview"}
diff --git a/pylint/checkers/format.py b/pylint/checkers/format.py
index 62466a4fd..3e3cd3227 100644
--- a/pylint/checkers/format.py
+++ b/pylint/checkers/format.py
@@ -13,11 +13,10 @@ Some parts of the process_token method is based from The Tab Nanny std module.
 
 from __future__ import annotations
 
-import sys
 import tokenize
 from functools import reduce
 from re import Match
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Literal
 
 from astroid import nodes
 
@@ -31,10 +30,6 @@ from pylint.utils.pragma_parser import OPTION_PO, PragmaParserError, parse_pragm
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
 
 _KEYWORD_TOKENS = {
     "assert",
diff --git a/pylint/checkers/imports.py b/pylint/checkers/imports.py
index 6cc5d2164..42649f3d9 100644
--- a/pylint/checkers/imports.py
+++ b/pylint/checkers/imports.py
@@ -12,6 +12,7 @@ import os
 import sys
 from collections import defaultdict
 from collections.abc import ItemsView, Sequence
+from functools import cached_property
 from typing import TYPE_CHECKING, Any, Dict, List, Union
 
 import astroid
@@ -38,11 +39,6 @@ from pylint.utils.linterstats import LinterStats
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-else:
-    from astroid.decorators import cachedproperty as cached_property
-
 
 # The dictionary with Any should actually be a _ImportTree again
 # but mypy doesn't support recursive types yet
diff --git a/pylint/checkers/logging.py b/pylint/checkers/logging.py
index e5fb1ae09..461047bdf 100644
--- a/pylint/checkers/logging.py
+++ b/pylint/checkers/logging.py
@@ -7,8 +7,7 @@
 from __future__ import annotations
 
 import string
-import sys
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Literal
 
 import astroid
 from astroid import bases, nodes
@@ -19,11 +18,6 @@ from pylint.checkers import utils
 from pylint.checkers.utils import infer_all
 from pylint.typing import MessageDefinitionTuple
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
diff --git a/pylint/checkers/raw_metrics.py b/pylint/checkers/raw_metrics.py
index 301e9d2e2..ef4535345 100644
--- a/pylint/checkers/raw_metrics.py
+++ b/pylint/checkers/raw_metrics.py
@@ -4,19 +4,13 @@
 
 from __future__ import annotations
 
-import sys
 import tokenize
-from typing import TYPE_CHECKING, Any, cast
+from typing import TYPE_CHECKING, Any, Literal, cast
 
 from pylint.checkers import BaseTokenChecker
 from pylint.reporters.ureports.nodes import Paragraph, Section, Table, Text
 from pylint.utils import LinterStats, diff_string
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
diff --git a/pylint/checkers/refactoring/refactoring_checker.py b/pylint/checkers/refactoring/refactoring_checker.py
index 890b0e64d..5d0a2dd7a 100644
--- a/pylint/checkers/refactoring/refactoring_checker.py
+++ b/pylint/checkers/refactoring/refactoring_checker.py
@@ -7,10 +7,9 @@ from __future__ import annotations
 import collections
 import copy
 import itertools
-import sys
 import tokenize
 from collections.abc import Iterator
-from functools import reduce
+from functools import cached_property, reduce
 from re import Pattern
 from typing import TYPE_CHECKING, Any, NamedTuple, Union, cast
 
@@ -27,10 +26,6 @@ from pylint.interfaces import HIGH, INFERENCE, Confidence
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-else:
-    from astroid.decorators import cachedproperty as cached_property
 
 NodesWithNestedBlocks = Union[
     nodes.TryExcept, nodes.TryFinally, nodes.While, nodes.For, nodes.If
diff --git a/pylint/checkers/spelling.py b/pylint/checkers/spelling.py
index 8ba4df4d5..91161c60d 100644
--- a/pylint/checkers/spelling.py
+++ b/pylint/checkers/spelling.py
@@ -7,21 +7,15 @@
 from __future__ import annotations
 
 import re
-import sys
 import tokenize
 from re import Pattern
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 from astroid import nodes
 
 from pylint.checkers import BaseTokenChecker
 from pylint.checkers.utils import only_required_for_messages
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
diff --git a/pylint/checkers/strings.py b/pylint/checkers/strings.py
index ce122e754..2cc780da5 100644
--- a/pylint/checkers/strings.py
+++ b/pylint/checkers/strings.py
@@ -8,11 +8,10 @@ from __future__ import annotations
 
 import collections
 import re
-import sys
 import tokenize
 from collections import Counter
 from collections.abc import Iterable, Sequence
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Literal
 
 import astroid
 from astroid import bases, nodes, util
@@ -26,11 +25,6 @@ from pylint.typing import MessageDefinitionTuple
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-if sys.version_info >= (3, 8):
-    from typing import Literal
-else:
-    from typing_extensions import Literal
-
 
 _AST_NODE_STR_TYPES = ("__builtin__.unicode", "__builtin__.str", "builtins.str")
 # Prefixes for both strings and bytes literals per
diff --git a/pylint/checkers/typecheck.py b/pylint/checkers/typecheck.py
index 0298c81dc..fe29879c5 100644
--- a/pylint/checkers/typecheck.py
+++ b/pylint/checkers/typecheck.py
@@ -14,9 +14,9 @@ import shlex
 import sys
 import types
 from collections.abc import Callable, Iterable, Iterator, Sequence
-from functools import singledispatch
+from functools import cached_property, singledispatch
 from re import Pattern
-from typing import TYPE_CHECKING, Any, TypeVar, Union
+from typing import TYPE_CHECKING, Any, Literal, TypeVar, Union
 
 import astroid
 import astroid.exceptions
@@ -53,13 +53,6 @@ from pylint.constants import PY310_PLUS
 from pylint.interfaces import HIGH, INFERENCE
 from pylint.typing import MessageDefinitionTuple
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-    from typing import Literal
-else:
-    from astroid.decorators import cachedproperty as cached_property
-    from typing_extensions import Literal
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py
index 95a0e7b7b..6b66ad620 100644
--- a/pylint/checkers/utils.py
+++ b/pylint/checkers/utils.py
@@ -1942,7 +1942,7 @@ def is_typing_member(node: nodes.NodeNG, names_to_check: tuple[str, ...]) -> boo
     return False
 
 
-@lru_cache()
+@lru_cache
 def in_for_else_branch(parent: nodes.NodeNG, stmt: nodes.Statement) -> bool:
     """Returns True if stmt is inside the else branch for a parent For stmt."""
     return isinstance(parent, nodes.For) and any(
diff --git a/pylint/checkers/variables.py b/pylint/checkers/variables.py
index e1b82bb41..08797c93c 100644
--- a/pylint/checkers/variables.py
+++ b/pylint/checkers/variables.py
@@ -11,10 +11,10 @@ import copy
 import itertools
 import os
 import re
-import sys
 from collections import defaultdict
 from collections.abc import Generator, Iterable, Iterator
 from enum import Enum
+from functools import cached_property
 from typing import TYPE_CHECKING, Any, NamedTuple
 
 import astroid
@@ -34,11 +34,6 @@ from pylint.constants import PY39_PLUS, TYPING_NEVER, TYPING_NORETURN
 from pylint.interfaces import CONTROL_FLOW, HIGH, INFERENCE, INFERENCE_FAILURE
 from pylint.typing import MessageDefinitionTuple
 
-if sys.version_info >= (3, 8):
-    from functools import cached_property
-else:
-    from astroid.decorators import cachedproperty as cached_property
-
 if TYPE_CHECKING:
     from pylint.lint import PyLinter