Drop Python 3.9 support in typespec-python

.chronus/changes/python-drop-py39-2026-04-27-06-52-15.md

@@ -0,0 +1,7 @@
+---
+changeKind: deprecation
+packages:
+  - "@azure-tools/typespec-python"
+---
+
+Drop support for Python 3.9. The minimum supported Python version is now 3.10.

packages/typespec-python/eng/scripts/ci/config/mypy.ini

@@ -1,6 +1,6 @@
 # global configurations
 [mypy]
-python_version = 3.9
+python_version = 3.10
 # Exclude mypy check for sub client tests
 exclude = (.*azure/clientgenerator/core/clientinitialization/operations/_operations\.py|.*azure/clientgenerator/core/clientinitialization/aio/operations/_operations\.py)
 

packages/typespec-python/eng/scripts/ci/config/pylintrc

@@ -1,5 +1,5 @@
 [MASTER]
-py-version=3.9
+py-version=3.10
 ignore-patterns=test_*,conftest,setup
 reports=no
 

packages/typespec-python/eng/scripts/ci/config/pyrightconfig.json

@@ -3,6 +3,6 @@
   "reportTypeCommentUsage": true,
   "reportMissingImports": false,
   "reportAttributeAccessIssue": false,
-  "pythonVersion": "3.9",
+  "pythonVersion": "3.10",
   "exclude": ["**/build/**"]
 }

packages/typespec-python/eng/scripts/ci/run_pylint.py

@@ -51,7 +51,7 @@ def _single_dir_pylint(mod):
                 "--output-format=parseable",
                 "--recursive=y",
                 "--ignore=build",
-                "--py-version=3.9",
+                "--py-version=3.10",
                 str(inner_class.absolute()),
             ]
         )

packages/typespec-python/eng/scripts/setup/install.py

@@ -7,8 +7,8 @@
 # --------------------------------------------------------------------------
 import sys
 
-if not sys.version_info >= (3, 9, 0):
-    raise Exception("Autorest for Python extension requires Python 3.9 at least")
+if not sys.version_info >= (3, 10, 0):
+    raise Exception("Autorest for Python extension requires Python 3.10 at least")
 
 try:
     from package_manager import detect_package_manager, PackageManagerNotFoundError
@@ -25,4 +25,4 @@
     raise Exception("Your Python installation doesn't have venv available")
 
 
-# Now we have a package manager (uv or pip) and Py >= 3.9 and check is over
+# Now we have a package manager (uv or pip) and Py >= 3.10 and check is over

packages/typespec-python/eng/scripts/setup/prepare.py

@@ -7,8 +7,8 @@
 # --------------------------------------------------------------------------
 import sys
 
-if not sys.version_info >= (3, 9, 0):
-    raise Exception("Autorest for Python extension requires Python 3.9 at least")
+if not sys.version_info >= (3, 10, 0):
+    raise Exception("Autorest for Python extension requires Python 3.10 at least")
 
 from pathlib import Path
 from package_manager import create_venv_with_package_manager, install_packages

packages/typespec-python/eng/scripts/setup/run-python3.ts

@@ -11,7 +11,7 @@ import { patchPythonPath } from "./system-requirements.js";
 
 async function runPython3(...args: string[]) {
   const command = await patchPythonPath(["python", ...args], {
-    version: ">=3.9",
+    version: ">=3.10",
     environmentVariable: "AUTOREST_PYTHON_EXE",
   });
   const [cmd, ...cmdArgs] = command;