chore: drop support for Python 3.9 (#641)

* Drop support for Python 3.9

- Update requires-python to >=3.10
- Remove Python 3.9 classifier
- Update CI to test Python 3.10+ only
- Update ruff target-version to py310
- Remove version checks for 3.9 in tests
- Update imports to use collections.abc.Callable
- Ignore UP045/UP007 for now with TODO to revisit separately

* rerun: to check if gpu actions are back

* re run

Author: bhimrazy

.github/workflows/ci-testing.yml

@@ -19,11 +19,11 @@ jobs:
       fail-fast: false
       matrix:
         os: ["ubuntu-latest"]
-        python-version: ["3.9", "3.10", "3.11"] # todo, "3.12"
+        python-version: ["3.10", "3.11"] # todo, "3.12"
         include:
           - { os: "macos-latest", python-version: "3.12" }
           - { os: "windows-latest", python-version: "3.11" }
-          - { os: "ubuntu-22.04", python-version: "3.9", requires: "oldest" }
+          - { os: "ubuntu-22.04", python-version: "3.10", requires: "oldest" }
 
     timeout-minutes: 35
     env:

pyproject.toml

@@ -11,7 +11,7 @@ license = {text = "Apache-2.0"}
 authors = [
     {name = "Lightning-AI et al.", email = "community@lightning.ai"}
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 keywords = ["deep learning", "pytorch", "AI"]
 classifiers = [
     "Environment :: Console",
@@ -23,8 +23,6 @@ classifiers = [
     "License :: OSI Approved :: Apache Software License",
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.8",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
@@ -110,7 +108,7 @@ blank = true
 
 [tool.ruff]
 line-length = 120
-target-version = "py39"
+target-version = "py310"
 # Enable Pyflakes `E` and `F` codes by default.
 lint.select = [
     "E", "W",  # see: https://pypi.org/project/pycodestyle
@@ -129,6 +127,8 @@ lint.extend-select = [
 ]
 lint.ignore = [
     "E731",  # Do not assign a lambda expression, use a def
+    "UP045",  # TODO: non-pep604-annotation-optional
+    "UP007",  # TODO: non-pep604-annotation-union
 ]
 # Exclude a variety of commonly ignored directories.
 exclude = [

src/litserve/api.py

@@ -16,9 +16,9 @@
 import json
 import warnings
 from abc import ABC
-from collections.abc import Awaitable
+from collections.abc import Awaitable, Callable
 from queue import Queue
-from typing import TYPE_CHECKING, Callable, Optional, Union
+from typing import TYPE_CHECKING, Optional, Union
 
 from pydantic import BaseModel
 

src/litserve/server.py

@@ -29,10 +29,10 @@
 import warnings
 from abc import ABC, abstractmethod
 from collections import deque
-from collections.abc import Iterable, Sequence
+from collections.abc import Callable, Iterable, Sequence
 from contextlib import asynccontextmanager
 from queue import Queue
-from typing import TYPE_CHECKING, Callable, Literal, Optional, Union
+from typing import TYPE_CHECKING, Literal, Optional, Union
 
 import uvicorn
 import uvicorn.server

src/litserve/specs/base.py

@@ -12,8 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from abc import abstractmethod
-from collections.abc import AsyncGenerator, Generator
-from typing import TYPE_CHECKING, Callable, Optional, Union
+from collections.abc import AsyncGenerator, Callable, Generator
+from typing import TYPE_CHECKING, Optional, Union
 
 if TYPE_CHECKING:
     from litserve import LitAPI, LitServer

tests/unit/test_cli.py

@@ -41,8 +41,8 @@ def test_ensure_lightning_installed(mock_check_call, mock_is_package_installed):
     mock_check_call.assert_called_once_with([sys.executable, "-m", "pip", "install", "-U", "lightning-sdk"])
 
 
-# TODO: Remove this once we have a fix for Python 3.9 and 3.10
-@pytest.mark.skipif(sys.version_info[:2] in [(3, 9), (3, 10)], reason="Test fails on Python 3.9 and 3.10")
+# TODO: Remove this once we have a fix for Python 3.10
+@pytest.mark.skipif(sys.version_info[:2] in [(3, 10)], reason="Test fails on Python 3.10")
 @patch("litserve.cli.is_package_installed")
 @patch("subprocess.check_call")
 @patch("builtins.__import__")
@@ -69,7 +69,7 @@ def side_effect(name, *args, **kwargs):
     mock_check_call.assert_called_once_with([sys.executable, "-m", "pip", "install", "-U", "lightning-sdk"])
 
 
-@pytest.mark.skipif(sys.version_info[:2] in [(3, 9), (3, 10)], reason="Test fails on Python 3.9 and 3.10")
+@pytest.mark.skipif(sys.version_info[:2] in [(3, 10)], reason="Test fails on Python 3.10")
 @patch("importlib.util.find_spec")
 @patch("builtins.__import__")
 def test_cli_main_import_error(mock_import, mock_find_spec, capsys):

tests/unit/test_mcp.py

@@ -1,5 +1,4 @@
 import inspect
-import sys
 from typing import Optional
 from unittest.mock import patch
 
@@ -8,9 +7,6 @@
 from pydantic import BaseModel, Field
 from starlette.applications import Starlette
 
-if sys.version_info < (3, 10):
-    pytest.skip("Skipping test_mcp.py on Python < 3.10", allow_module_level=True)
-
 import litserve as ls
 from litserve.mcp import (
     MCP,