readd Python 3.9 support

Author: loechel

.github/workflows/tests.yml

@@ -25,6 +25,7 @@ jobs:
         config:
         # [Python version, tox env]
         - ["3.14", "release-check"]
+        - ["3.9", "py39"]
         - ["3.10", "py310"]
         - ["3.11", "py311"]
         - ["3.12", "py312"]

.meta.toml

@@ -47,7 +47,7 @@ testenv-additional = [
     "    coverage combine",
     "    coverage html",
     "    coverage report -m --fail-under=100",
-    "depends = py310,py311,py312,py313,py314,py314-datetime,coverage",
+    "depends = py39,py310,py311,py312,py313,py314,py314-datetime,coverage",
     ]
 coverage-command = "pytest --cov=src --cov=tests --cov-report= tests {posargs}"
 coverage-setenv = [

setup.py

@@ -61,7 +61,7 @@ def read(*rnames):
       packages=find_packages('src'),
       package_dir={'': 'src'},
       install_requires=[],
-      python_requires=">=3.10, <3.15",
+      python_requires=">=3.9, <3.15",
       extras_require={
           'test': ['pytest', 'pytest-mock'],
           'typecheck': ['mypy', 'typeshed'],

src/RestrictedPython/compile.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import ast
 import warnings
 from ast import Expression
@@ -8,15 +10,20 @@
 from os import PathLike
 from typing import Any
 from typing import Literal
-from typing import TypeAlias
 
 from RestrictedPython._compat import IS_CPYTHON
+from RestrictedPython._compat import IS_PY310_OR_GREATER
 from RestrictedPython.transformer import RestrictingNodeTransformer
 
 
-# Temporary workaround for missing _typeshed
-ReadableBuffer: TypeAlias = bytes | bytearray
+if IS_PY310_OR_GREATER:
+    from typing import TypeAlias
 
+    # Temporary workaround for missing _typeshed
+    ReadableBuffer: TypeAlias = bytes | bytearray
+else:
+    from typing_extensions import TypeAlias  # type: ignore[import]
+    ReadableBuffer: TypeAlias = bytes | bytearray  # type: ignore[no-redef]
 
 CompileResult = namedtuple(
     'CompileResult', 'code, errors, warnings, used_names')

tox.ini

@@ -5,6 +5,7 @@ minversion = 3.18
 envlist =
     release-check
     lint
+    py39
     py310
     py311
     py312