Use typing.Literal available in Python 3.8+ (#3365)

docs/conf.py

@@ -110,7 +110,6 @@
     ("py:class", "_HttplibHTTPResponse"),
     ("py:class", "_HttplibHTTPMessage"),
     ("py:class", "TracebackType"),
-    ("py:class", "Literal"),
     ("py:class", "email.errors.MessageDefect"),
     ("py:class", "MessageDefect"),
     ("py:class", "http.client.HTTPMessage"),

src/urllib3/_base_connection.py

@@ -12,7 +12,7 @@
 class ProxyConfig(typing.NamedTuple):
     ssl_context: ssl.SSLContext | None
     use_forwarding_for_https: bool
-    assert_hostname: None | str | Literal[False]
+    assert_hostname: None | str | typing.Literal[False]
     assert_fingerprint: str | None
 
 
@@ -28,7 +28,7 @@ class _ResponseOptions(typing.NamedTuple):
 
 if typing.TYPE_CHECKING:
     import ssl
-    from typing import Literal, Protocol
+    from typing import Protocol
 
     from .response import BaseHTTPResponse
 
@@ -124,7 +124,7 @@ class BaseHTTPSConnection(BaseHTTPConnection, Protocol):
 
         # Certificate verification methods
         cert_reqs: int | str | None
-        assert_hostname: None | str | Literal[False]
+        assert_hostname: None | str | typing.Literal[False]
         assert_fingerprint: str | None
         ssl_context: ssl.SSLContext | None
 
@@ -155,7 +155,7 @@ def __init__(
             proxy: Url | None = None,
             proxy_config: ProxyConfig | None = None,
             cert_reqs: int | str | None = None,
-            assert_hostname: None | str | Literal[False] = None,
+            assert_hostname: None | str | typing.Literal[False] = None,
             assert_fingerprint: str | None = None,
             server_hostname: str | None = None,
             ssl_context: ssl.SSLContext | None = None,

src/urllib3/connection.py

@@ -14,8 +14,6 @@
 from socket import timeout as SocketTimeout
 
 if typing.TYPE_CHECKING:
-    from typing import Literal
-
     from .response import HTTPResponse
     from .util.ssl_ import _TYPE_PEER_CERT_RET_DICT
     from .util.ssltransport import SSLTransport
@@ -523,7 +521,7 @@ def __init__(
         proxy: Url | None = None,
         proxy_config: ProxyConfig | None = None,
         cert_reqs: int | str | None = None,
-        assert_hostname: None | str | Literal[False] = None,
+        assert_hostname: None | str | typing.Literal[False] = None,
         assert_fingerprint: str | None = None,
         server_hostname: str | None = None,
         ssl_context: ssl.SSLContext | None = None,
@@ -577,7 +575,7 @@ def set_cert(
         cert_reqs: int | str | None = None,
         key_password: str | None = None,
         ca_certs: str | None = None,
-        assert_hostname: None | str | Literal[False] = None,
+        assert_hostname: None | str | typing.Literal[False] = None,
         assert_fingerprint: str | None = None,
         ca_cert_dir: str | None = None,
         ca_cert_data: None | str | bytes = None,
@@ -742,7 +740,7 @@ def _ssl_wrap_socket_and_match_hostname(
     ca_certs: str | None,
     ca_cert_dir: str | None,
     ca_cert_data: None | str | bytes,
-    assert_hostname: None | str | Literal[False],
+    assert_hostname: None | str | typing.Literal[False],
     assert_fingerprint: str | None,
     server_hostname: str | None,
     ssl_context: ssl.SSLContext | None,

src/urllib3/connectionpool.py

@@ -53,7 +53,6 @@
 
 if typing.TYPE_CHECKING:
     import ssl
-    from typing import Literal
 
     from typing_extensions import Self
 
@@ -103,7 +102,7 @@ def __exit__(
         exc_type: type[BaseException] | None,
         exc_val: BaseException | None,
         exc_tb: TracebackType | None,
-    ) -> Literal[False]:
+    ) -> typing.Literal[False]:
         self.close()
         # Return False to re-raise any potential exceptions
         return False
@@ -1002,7 +1001,7 @@ def __init__(
         ssl_version: int | str | None = None,
         ssl_minimum_version: ssl.TLSVersion | None = None,
         ssl_maximum_version: ssl.TLSVersion | None = None,
-        assert_hostname: str | Literal[False] | None = None,
+        assert_hostname: str | typing.Literal[False] | None = None,
         assert_fingerprint: str | None = None,
         ca_cert_dir: str | None = None,
         **conn_kw: typing.Any,

src/urllib3/contrib/socks.py

@@ -71,10 +71,8 @@
 except ImportError:
     ssl = None  # type: ignore[assignment]
 
-from typing import TypedDict
 
-
-class _TYPE_SOCKS_OPTIONS(TypedDict):
+class _TYPE_SOCKS_OPTIONS(typing.TypedDict):
     socks_version: int
     proxy_host: str | None
     proxy_port: str | None

src/urllib3/poolmanager.py

@@ -26,7 +26,6 @@
 
 if typing.TYPE_CHECKING:
     import ssl
-    from typing import Literal
 
     from typing_extensions import Self
 
@@ -222,7 +221,7 @@ def __exit__(
         exc_type: type[BaseException] | None,
         exc_val: BaseException | None,
         exc_tb: TracebackType | None,
-    ) -> Literal[False]:
+    ) -> typing.Literal[False]:
         self.clear()
         # Return False to re-raise any potential exceptions
         return False
@@ -553,7 +552,7 @@ def __init__(
         proxy_headers: typing.Mapping[str, str] | None = None,
         proxy_ssl_context: ssl.SSLContext | None = None,
         use_forwarding_for_https: bool = False,
-        proxy_assert_hostname: None | str | Literal[False] = None,
+        proxy_assert_hostname: None | str | typing.Literal[False] = None,
         proxy_assert_fingerprint: str | None = None,
         **connection_pool_kw: typing.Any,
     ) -> None:

src/urllib3/response.py

@@ -62,8 +62,6 @@
 from .util.retry import Retry
 
 if typing.TYPE_CHECKING:
-    from typing import Literal
-
     from .connectionpool import HTTPConnectionPool
 
 log = logging.getLogger(__name__)
@@ -347,7 +345,7 @@ def __init__(
         self._decoder: ContentDecoder | None = None
         self.length_remaining: int | None
 
-    def get_redirect_location(self) -> str | None | Literal[False]:
+    def get_redirect_location(self) -> str | None | typing.Literal[False]:
         """
         Should we redirect and where to?
 

src/urllib3/util/ssl_.py

@@ -78,7 +78,7 @@ def _is_has_never_check_common_name_reliable(
 
 if typing.TYPE_CHECKING:
     from ssl import VerifyMode
-    from typing import Literal, TypedDict
+    from typing import TypedDict
 
     from .ssltransport import SSLTransport as SSLTransportType
 
@@ -365,7 +365,7 @@ def ssl_wrap_socket(
     ca_cert_dir: str | None = ...,
     key_password: str | None = ...,
     ca_cert_data: None | str | bytes = ...,
-    tls_in_tls: Literal[False] = ...,
+    tls_in_tls: typing.Literal[False] = ...,
 ) -> ssl.SSLSocket:
     ...
 

src/urllib3/util/ssltransport.py

@@ -8,8 +8,6 @@
 from ..exceptions import ProxySchemeUnsupported
 
 if typing.TYPE_CHECKING:
-    from typing import Literal
-
     from typing_extensions import Self
 
     from .ssl_ import _TYPE_PEER_CERT_RET, _TYPE_PEER_CERT_RET_DICT
@@ -175,12 +173,12 @@ def close(self) -> None:
 
     @typing.overload
     def getpeercert(
-        self, binary_form: Literal[False] = ...
+        self, binary_form: typing.Literal[False] = ...
     ) -> _TYPE_PEER_CERT_RET_DICT | None:
         ...
 
     @typing.overload
-    def getpeercert(self, binary_form: Literal[True]) -> bytes | None:
+    def getpeercert(self, binary_form: typing.Literal[True]) -> bytes | None:
         ...
 
     def getpeercert(self, binary_form: bool = False) -> _TYPE_PEER_CERT_RET:

test/__init__.py

@@ -44,7 +44,6 @@
 
 if typing.TYPE_CHECKING:
     import ssl
-    from typing import Literal
 
 
 _RT = typing.TypeVar("_RT")  # return type
@@ -266,7 +265,7 @@ def __exit__(
         exc_type: type[BaseException] | None,
         exc_value: BaseException | None,
         traceback: TracebackType | None,
-    ) -> Literal[False]:
+    ) -> typing.Literal[False]:
         self.uninstall()
         return False
 

test/test_ssltransport.py

@@ -14,9 +14,6 @@
 from urllib3.util import ssl_
 from urllib3.util.ssltransport import SSLTransport
 
-if typing.TYPE_CHECKING:
-    from typing import Literal
-
 # consume_socket can iterate forever, we add timeouts to prevent halting.
 PER_TEST_TIMEOUT = 60
 
@@ -34,12 +31,12 @@ def server_client_ssl_contexts() -> tuple[ssl.SSLContext, ssl.SSLContext]:
 
 
 @typing.overload
-def sample_request(binary: Literal[True] = ...) -> bytes:
+def sample_request(binary: typing.Literal[True] = ...) -> bytes:
     ...
 
 
 @typing.overload
-def sample_request(binary: Literal[False]) -> str:
+def sample_request(binary: typing.Literal[False]) -> str:
     ...
 
 
@@ -54,20 +51,20 @@ def sample_request(binary: bool = True) -> bytes | str:
 
 
 def validate_request(
-    provided_request: bytearray, binary: Literal[False, True] = True
+    provided_request: bytearray, binary: typing.Literal[False, True] = True
 ) -> None:
     assert provided_request is not None
     expected_request = sample_request(binary)
     assert provided_request == expected_request
 
 
 @typing.overload
-def sample_response(binary: Literal[True] = ...) -> bytes:
+def sample_response(binary: typing.Literal[True] = ...) -> bytes:
     ...
 
 
 @typing.overload
-def sample_response(binary: Literal[False]) -> str:
+def sample_response(binary: typing.Literal[False]) -> str:
     ...
 
 

test/test_util.py

@@ -41,9 +41,6 @@
 
 from . import clear_warnings
 
-if typing.TYPE_CHECKING:
-    from typing import Literal
-
 # This number represents a time in seconds, it doesn't mean anything in
 # isolation. Setting to a high-ish value to avoid conflicts with the smaller
 # numbers used for timeouts
@@ -516,7 +513,7 @@ def test_netloc(self, url: str, expected_netloc: str | None) -> None:
 
     @pytest.mark.parametrize("url, expected_url", url_vulnerabilities)
     def test_url_vulnerabilities(
-        self, url: str, expected_url: Literal[False] | Url
+        self, url: str, expected_url: typing.Literal[False] | Url
     ) -> None:
         if expected_url is False:
             with pytest.raises(LocationParseError):
@@ -748,7 +745,7 @@ def test_timeout_elapsed(self, time_monotonic: MagicMock) -> None:
     def test_is_fp_closed_object_supports_closed(self) -> None:
         class ClosedFile:
             @property
-            def closed(self) -> Literal[True]:
+            def closed(self) -> typing.Literal[True]:
                 return True
 
         assert is_fp_closed(ClosedFile())
@@ -764,7 +761,7 @@ def fp(self) -> None:
     def test_is_fp_closed_object_has_fp(self) -> None:
         class FpFile:
             @property
-            def fp(self) -> Literal[True]:
+            def fp(self) -> typing.Literal[True]:
                 return True
 
         assert not is_fp_closed(FpFile())