Drop support for Python 3.9

.github/workflows/primer-test.yaml

@@ -30,7 +30,7 @@ jobs:
     timeout-minutes: 5
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     outputs:
       python-key: ${{ steps.generate-python-key.outputs.key }}
     steps:
@@ -72,7 +72,7 @@ jobs:
     needs: prepare-tests-linux
     strategy:
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     steps:
       - name: Check out code from GitHub
         uses: actions/checkout@v4.2.2

.github/workflows/primer_run_main.yaml

@@ -29,7 +29,7 @@ jobs:
     timeout-minutes: 45
     strategy:
       matrix:
-        python-version: ["3.9", "3.13"]
+        python-version: ["3.10", "3.13"]
         batches: [4]
         batchIdx: [0, 1, 2, 3]
     steps:

.github/workflows/primer_run_pr.yaml

@@ -38,7 +38,7 @@ jobs:
     timeout-minutes: 45
     strategy:
       matrix:
-        python-version: ["3.9", "3.13"]
+        python-version: ["3.10", "3.13"]
         batches: [4]
         batchIdx: [0, 1, 2, 3]
     steps:
@@ -217,7 +217,8 @@ jobs:
           echo ${{ github.event.pull_request.number }} | tee pr_number.txt
       - name: Upload PR number
         if:
-          startsWith(steps.python.outputs.python-version, '3.9') && matrix.batchIdx == 0
+          startsWith(steps.python.outputs.python-version, '3.10') && matrix.batchIdx ==
+          0
         uses: actions/upload-artifact@v4.6.2
         with:
           name: pr_number

.github/workflows/tests.yaml

@@ -31,12 +31,10 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
         include:
           - os: macos-latest
-            python-version: "3.9"
-          - os: ubuntu-latest
-            python-version: "pypy-3.9"
+            python-version: "3.10"
           - os: ubuntu-latest
             python-version: "pypy-3.10"
           - os: ubuntu-latest
@@ -190,7 +188,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
     steps:
       - name: Set temp directory
         run: echo "TEMP=$env:USERPROFILE\AppData\Local\Temp" >> $env:GITHUB_ENV

README.rst

@@ -45,7 +45,7 @@ What is Pylint?
 ---------------
 
 Pylint is a `static code analyser`_ for Python 2 or 3. The latest version supports Python
-3.9.0 and above.
+3.10.0 and above.
 
 .. _`static code analyser`: https://en.wikipedia.org/wiki/Static_code_analysis
 

doc/whatsnew/fragments/10405.other

@@ -0,0 +1,4 @@
+Remove support for launching pylint with Python 3.9.
+Code that supports Python 3.9 can still be linted with the ``--py-version=3.9`` setting.
+
+Refs #10405

pylint/checkers/base/basic_checker.py

@@ -884,7 +884,7 @@ def visit_with(self, node: nodes.With) -> None:
         # to one AST "With" node with multiple items
         pairs = node.items
         if pairs:
-            for prev_pair, pair in zip(pairs, pairs[1:]):
+            for prev_pair, pair in itertools.pairwise(pairs):
                 if isinstance(prev_pair[1], nodes.AssignName) and (
                     pair[1] is None and not isinstance(pair[0], nodes.Call)
                 ):

pylint/checkers/classes/class_checker.py

@@ -11,7 +11,7 @@
 from functools import cached_property
 from itertools import chain, zip_longest
 from re import Pattern
-from typing import TYPE_CHECKING, Any, NamedTuple, Union
+from typing import TYPE_CHECKING, Any, NamedTuple, TypeAlias
 
 import astroid
 from astroid import bases, nodes, util
@@ -46,7 +46,7 @@
     from pylint.lint.pylinter import PyLinter
 
 
-_AccessNodes = Union[nodes.Attribute, nodes.AssignAttr]
+_AccessNodes: TypeAlias = nodes.Attribute | nodes.AssignAttr
 
 INVALID_BASE_CLASSES = {"bool", "range", "slice", "memoryview"}
 ALLOWED_PROPERTIES = {"bultins.property", "functools.cached_property"}

pylint/checkers/imports.py

@@ -13,7 +13,7 @@
 from collections import defaultdict
 from collections.abc import ItemsView, Sequence
 from functools import cached_property
-from typing import TYPE_CHECKING, Any, Union
+from typing import TYPE_CHECKING, Any
 
 import astroid
 from astroid import nodes
@@ -43,7 +43,7 @@
 
 # The dictionary with Any should actually be a _ImportTree again
 # but mypy doesn't support recursive types yet
-_ImportTree = dict[str, Union[list[dict[str, Any]], list[str]]]
+_ImportTree = dict[str, list[dict[str, Any]] | list[str]]
 
 DEPRECATED_MODULES = {
     (0, 0, 0): {"tkinter.tix", "fpectl"},

pylint/checkers/refactoring/refactoring_checker.py

@@ -11,7 +11,7 @@
 from collections.abc import Iterator
 from functools import cached_property, reduce
 from re import Pattern
-from typing import TYPE_CHECKING, Any, NamedTuple, Union, cast
+from typing import TYPE_CHECKING, Any, NamedTuple, TypeAlias, cast
 
 import astroid
 from astroid import bases, nodes
@@ -27,7 +27,7 @@
     from pylint.lint import PyLinter
 
 
-NodesWithNestedBlocks = Union[nodes.Try, nodes.While, nodes.For, nodes.If]
+NodesWithNestedBlocks: TypeAlias = nodes.Try | nodes.While | nodes.For | nodes.If
 
 KNOWN_INFINITE_ITERATORS = {"itertools.count", "itertools.cycle"}
 BUILTIN_EXIT_FUNCS = frozenset(("quit", "exit"))

pylint/checkers/symilar.py

@@ -41,7 +41,7 @@
 from collections.abc import Callable, Generator, Iterable, Sequence
 from io import BufferedIOBase, BufferedReader, BytesIO
 from itertools import chain
-from typing import TYPE_CHECKING, NamedTuple, NewType, NoReturn, TextIO, Union
+from typing import TYPE_CHECKING, NamedTuple, NewType, NoReturn, TextIO, TypeAlias
 
 import astroid
 from astroid import nodes
@@ -79,7 +79,7 @@ class LineSpecifs(NamedTuple):
 IndexToLines_T = dict[Index, "SuccessiveLinesLimits"]
 
 # The types the streams read by pylint can take. Originating from astroid.nodes.Module.stream() and open()
-STREAM_TYPES = Union[TextIO, BufferedReader, BytesIO]
+STREAM_TYPES: TypeAlias = TextIO | BufferedReader | BytesIO
 
 
 class CplSuccessiveLinesLimits:

pylint/checkers/typecheck.py

@@ -15,7 +15,7 @@
 from collections.abc import Callable, Iterable
 from functools import cached_property, lru_cache, singledispatch
 from re import Pattern
-from typing import TYPE_CHECKING, Any, Literal, Union
+from typing import TYPE_CHECKING, Any, Literal, TypeAlias
 
 import astroid
 import astroid.exceptions
@@ -49,20 +49,19 @@
     supports_membership_test,
     supports_setitem,
 )
-from pylint.constants import PY310_PLUS
 from pylint.interfaces import HIGH, INFERENCE
 from pylint.typing import MessageDefinitionTuple
 
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-CallableObjects = Union[
-    bases.BoundMethod,
-    bases.UnboundMethod,
-    nodes.FunctionDef,
-    nodes.Lambda,
-    nodes.ClassDef,
-]
+CallableObjects: TypeAlias = (
+    bases.BoundMethod
+    | bases.UnboundMethod
+    | nodes.FunctionDef
+    | nodes.Lambda
+    | nodes.ClassDef
+)
 
 STR_FORMAT = {"builtins.str.format"}
 ASYNCIO_COROUTINE = "asyncio.coroutines.coroutine"
@@ -796,7 +795,7 @@ def _is_c_extension(module_node: InferenceResult) -> bool:
 
 def _is_invalid_isinstance_type(arg: nodes.NodeNG) -> bool:
     # Return True if we are sure that arg is not a type
-    if PY310_PLUS and isinstance(arg, nodes.BinOp) and arg.op == "|":
+    if isinstance(arg, nodes.BinOp) and arg.op == "|":
         return any(
             _is_invalid_isinstance_type(elt) and not is_none(elt)
             for elt in (arg.left, arg.right)
@@ -811,7 +810,7 @@ def _is_invalid_isinstance_type(arg: nodes.NodeNG) -> bool:
         return False
     if isinstance(inferred, astroid.Instance) and inferred.qname() == BUILTIN_TUPLE:
         return False
-    if PY310_PLUS and isinstance(inferred, bases.UnionType):
+    if isinstance(inferred, bases.UnionType):
         return any(
             _is_invalid_isinstance_type(elt) and not is_none(elt)
             for elt in (inferred.left, inferred.right)

pylint/config/_pylint_config/utils.py

@@ -9,12 +9,7 @@
 import sys
 from collections.abc import Callable
 from pathlib import Path
-from typing import Literal, TypeVar
-
-if sys.version_info >= (3, 10):
-    from typing import ParamSpec
-else:
-    from typing_extensions import ParamSpec
+from typing import Literal, ParamSpec, TypeVar
 
 _P = ParamSpec("_P")
 _ReturnValueT = TypeVar("_ReturnValueT", bool, str)

pylint/config/argument.py

@@ -16,23 +16,23 @@
 from collections.abc import Callable, Sequence
 from glob import glob
 from re import Pattern
-from typing import Any, Literal, Union
+from typing import Any, Literal
 
 from pylint import interfaces
 from pylint import utils as pylint_utils
 from pylint.config.callback_actions import _CallbackAction
 from pylint.config.deprecation_actions import _NewNamesAction, _OldNamesAction
 
-_ArgumentTypes = Union[
-    str,
-    int,
-    float,
-    bool,
-    Pattern[str],
-    Sequence[str],
-    Sequence[Pattern[str]],
-    tuple[int, ...],
-]
+_ArgumentTypes = (
+    str
+    | int
+    | float
+    | bool
+    | Pattern[str]
+    | Sequence[str]
+    | Sequence[Pattern[str]]
+    | tuple[int, ...]
+)
 """List of possible argument types."""
 
 

pylint/constants.py

@@ -14,7 +14,6 @@
 from pylint.__pkginfo__ import __version__
 from pylint.typing import MessageTypesFullName
 
-PY310_PLUS = sys.version_info[:2] >= (3, 10)
 PY311_PLUS = sys.version_info[:2] >= (3, 11)
 PY312_PLUS = sys.version_info[:2] >= (3, 12)
 PY314_PLUS = sys.version_info[:2] >= (3, 14)

pylint/extensions/code_style.py

@@ -4,8 +4,7 @@
 
 from __future__ import annotations
 
-import sys
-from typing import TYPE_CHECKING, cast
+from typing import TYPE_CHECKING, TypeGuard, cast
 
 from astroid import nodes
 
@@ -16,11 +15,6 @@
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-if sys.version_info >= (3, 10):
-    from typing import TypeGuard
-else:
-    from typing_extensions import TypeGuard
-
 
 class CodeStyleChecker(BaseChecker):
     """Checkers that can improve code consistency.

pylint/extensions/mccabe.py

@@ -7,7 +7,7 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
-from typing import TYPE_CHECKING, Any, TypeVar, Union
+from typing import TYPE_CHECKING, Any, TypeAlias, TypeVar
 
 from astroid import nodes
 from mccabe import PathGraph as Mccabe_PathGraph
@@ -20,28 +20,28 @@
 if TYPE_CHECKING:
     from pylint.lint import PyLinter
 
-_StatementNodes = Union[
-    nodes.Assert,
-    nodes.Assign,
-    nodes.AugAssign,
-    nodes.Delete,
-    nodes.Raise,
-    nodes.Yield,
-    nodes.Import,
-    nodes.Call,
-    nodes.Subscript,
-    nodes.Pass,
-    nodes.Continue,
-    nodes.Break,
-    nodes.Global,
-    nodes.Return,
-    nodes.Expr,
-    nodes.Await,
-]
-
-_SubGraphNodes = Union[nodes.If, nodes.Try, nodes.For, nodes.While]
+_StatementNodes: TypeAlias = (
+    nodes.Assert
+    | nodes.Assign
+    | nodes.AugAssign
+    | nodes.Delete
+    | nodes.Raise
+    | nodes.Yield
+    | nodes.Import
+    | nodes.Call
+    | nodes.Subscript
+    | nodes.Pass
+    | nodes.Continue
+    | nodes.Break
+    | nodes.Global
+    | nodes.Return
+    | nodes.Expr
+    | nodes.Await
+)
+
+_SubGraphNodes: TypeAlias = nodes.If | nodes.Try | nodes.For | nodes.While
 _AppendableNodeT = TypeVar(
-    "_AppendableNodeT", bound=Union[_StatementNodes, nodes.While, nodes.FunctionDef]
+    "_AppendableNodeT", bound=_StatementNodes | nodes.While | nodes.FunctionDef
 )
 
 

pylint/pyreverse/inspector.py

@@ -14,7 +14,6 @@
 import traceback
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Sequence
-from typing import Optional
 
 import astroid
 from astroid import nodes
@@ -24,7 +23,7 @@
 from pylint.pyreverse import utils
 
 _WrapperFuncT = Callable[
-    [Callable[[str], nodes.Module], str, bool], Optional[nodes.Module]
+    [Callable[[str], nodes.Module], str, bool], nodes.Module | None
 ]
 
 

pylint/pyreverse/utils.py

@@ -12,7 +12,7 @@
 import subprocess
 import sys
 from collections.abc import Callable
-from typing import TYPE_CHECKING, Any, Optional, Union
+from typing import TYPE_CHECKING, Any
 
 import astroid
 from astroid import nodes
@@ -23,9 +23,9 @@
 
     _CallbackT = Callable[
         [nodes.NodeNG],
-        Union[tuple[ClassDiagram], tuple[PackageDiagram, ClassDiagram], None],
+        tuple[ClassDiagram] | tuple[PackageDiagram, ClassDiagram] | None,
     ]
-    _CallbackTupleT = tuple[Optional[_CallbackT], Optional[_CallbackT]]
+    _CallbackTupleT = tuple[_CallbackT | None, _CallbackT | None]
 
 
 RCFILE = ".pyreverserc"