chore: fix compatibility with 3.9, 3.10

The `typing.Self` annotation was only introduced in Python 3.11, and
therefore we have to rely on the typing extensions for versions 3.9 and
3.10.

There are also issues with TypeAliases and the use of the `|` operator.

Signed-off-by: JP-Ellis <josh@jpellis.me>

Author: JP-Ellis

src/pact/v3/_server.py

@@ -28,9 +28,11 @@
 from collections.abc import Callable
 from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
 from threading import Thread
-from typing import TYPE_CHECKING, Any, Generic, Self, TypeVar
+from typing import TYPE_CHECKING, Any, Generic, TypeVar
 from urllib.parse import urlparse
 
+from typing_extensions import Self
+
 from pact import __version__
 from pact.v3._util import find_free_port
 

src/pact/v3/types.py

@@ -9,7 +9,7 @@
 from __future__ import annotations
 
 from collections.abc import Callable
-from typing import Any, TypedDict
+from typing import Any, Optional, TypedDict, Union
 
 from typing_extensions import TypeAlias
 from yarl import URL
@@ -57,7 +57,7 @@ class Message(TypedDict):
     """
 
 
-MessageProducerFull: TypeAlias = Callable[[str, dict[str, Any] | None], Message]
+MessageProducerFull: TypeAlias = Callable[[str, Optional[dict[str, Any]]], Message]
 """
 Full message producer signature.
 
@@ -69,7 +69,7 @@ class Message(TypedDict):
 The function must return a `bytes` object.
 """
 
-MessageProducerNoName: TypeAlias = Callable[[dict[str, Any] | None], Message]
+MessageProducerNoName: TypeAlias = Callable[[Optional[dict[str, Any]]], Message]
 """
 Message producer signature without the name.
 
@@ -83,7 +83,7 @@ class Message(TypedDict):
 functions.
 """
 
-StateHandlerFull: TypeAlias = Callable[[str, str, dict[str, Any] | None], None]
+StateHandlerFull: TypeAlias = Callable[[str, str, Optional[dict[str, Any]]], None]
 """
 Full state handler signature.
 
@@ -93,7 +93,7 @@ class Message(TypedDict):
 2.  The action (either `setup` or `teardown`), as a string.
 3.  A dictionary of parameters, or `None` if no parameters are provided.
 """
-StateHandlerNoAction: TypeAlias = Callable[[str, dict[str, Any] | None], None]
+StateHandlerNoAction: TypeAlias = Callable[[str, Optional[dict[str, Any]]], None]
 """
 State handler signature without the action.
 
@@ -102,7 +102,7 @@ class Message(TypedDict):
 1.  The state name, as a string.
 2.  A dictionary of parameters, or `None` if no parameters are provided.
 """
-StateHandlerNoState: TypeAlias = Callable[[str, dict[str, Any] | None], None]
+StateHandlerNoState: TypeAlias = Callable[[str, Optional[dict[str, Any]]], None]
 """
 State handler signature without the state.
 
@@ -114,7 +114,7 @@ class Message(TypedDict):
 This function must be provided as part of a dictionary mapping state names to
 functions.
 """
-StateHandlerNoActionNoState: TypeAlias = Callable[[dict[str, Any] | None], None]
+StateHandlerNoActionNoState: TypeAlias = Callable[[Optional[dict[str, Any]]], None]
 """
 State handler signature without the state or action.
 
@@ -125,7 +125,7 @@ class Message(TypedDict):
 This function must be provided as part of a dictionary mapping state names to
 functions.
 """
-StateHandlerUrl: TypeAlias = str | URL
+StateHandlerUrl: TypeAlias = Union[str, URL]
 """
 State handler URL signature.
 

src/pact/v3/verifier.py

@@ -573,7 +573,9 @@ def state_handler(
                 providing one or more handler functions; and it must be set to
                 a boolean if providing a URL.
         """
-        if isinstance(handler, StateHandlerUrl):
+        # A tuple is required instead of `StateHandlerUrl` for support for
+        # Python 3.9. This should be changed to `StateHandlerUrl` in the future.
+        if isinstance(handler, (str, URL)):
             if body is None:
                 msg = "The `body` parameter must be a boolean when providing a URL"
                 raise ValueError(msg)

tests/v3/compatibility_suite/util/provider.py

@@ -26,13 +26,14 @@
 from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
 from io import BytesIO
 from threading import Thread
-from typing import TYPE_CHECKING, Any, ClassVar, Self, TypedDict
+from typing import TYPE_CHECKING, Any, ClassVar, TypedDict
 from unittest.mock import MagicMock
 
 import pytest
 import requests
 from multidict import CIMultiDict
 from pytest_bdd import given, parsers, then, when
+from typing_extensions import Self
 from yarl import URL
 
 import pact.constants  # type: ignore[import-untyped]