fix(auth): implement conditional base classes using TYPE_CHECKING in requests and urllib3 transports

Author: hebaalazzeh

packages/google-auth/google/auth/transport/requests.py

@@ -24,7 +24,6 @@
 import time
 from typing import Optional, Set, TYPE_CHECKING
 
-
 # PEP 0810: Explicit Lazy Imports
 # Python 3.15+ natively intercepts and defers these imports.
 # Developers can disable this behavior and force eager imports.
@@ -54,13 +53,18 @@
     create_urllib3_context,
 )  # pylint: disable=ungrouped-imports
 
-from google.auth import _helpers
-from google.auth import exceptions
-from google.auth import transport
+from google.auth import _helpers, exceptions, transport
 from google.auth.transport import _mtls_helper
 import google.auth.transport._mtls_helper
 from google.oauth2 import service_account
 
+if TYPE_CHECKING:
+    _HTTPAdapterBase = requests.adapters.HTTPAdapter
+    _SessionBase = requests.Session
+else:
+    _HTTPAdapterBase = _helpers.HeapDummy
+    _SessionBase = _helpers.HeapDummy
+
 
 class _LazyBasesMeta(_helpers.LazyBasesMeta):
     def _perform_resolve_bases(cls):
@@ -194,7 +198,7 @@ def __call__(
         body=None,
         headers=None,
         timeout=_DEFAULT_TIMEOUT,
-        **kwargs
+        **kwargs,
     ):
         """Make an HTTP request using requests.
 
@@ -242,9 +246,10 @@ class _MutualTlsAdapter(_HTTPAdapterBase, metaclass=_LazyBasesMeta):
     """
 
     def __init__(self, cert, key):
-        import certifi
         import ssl
 
+        import certifi
+
         ctx_poolmanager = create_urllib3_context()
         ctx_poolmanager.load_verify_locations(cafile=certifi.where())
 
@@ -318,6 +323,7 @@ class _MutualTlsOffloadAdapter(_HTTPAdapterBase, metaclass=_LazyBasesMeta):
 
     def __init__(self, enterprise_cert_file_path):
         import certifi
+
         from google.auth.transport import _custom_tls_signer
 
         self.signer = _custom_tls_signer.CustomTlsSigner(enterprise_cert_file_path)
@@ -537,7 +543,7 @@ def request(
         headers=None,
         max_allowed_time=None,
         timeout=_DEFAULT_TIMEOUT,
-        **kwargs
+        **kwargs,
     ):
         """Implementation of Requests' request.
 
@@ -599,7 +605,7 @@ def request(
                 data=data,
                 headers=request_headers,
                 timeout=timeout,
-                **kwargs
+                **kwargs,
             )
         remaining_time = guard.remaining_timeout
 
@@ -671,7 +677,7 @@ def request(
                 max_allowed_time=remaining_time,
                 timeout=timeout,
                 _credential_refresh_attempt=_credential_refresh_attempt + 1,
-                **kwargs
+                **kwargs,
             )
 
         return response

packages/google-auth/google/auth/transport/urllib3.py

@@ -16,7 +16,6 @@
 
 from __future__ import absolute_import
 
-
 import http.client as http_client
 import logging
 from typing import Set, TYPE_CHECKING
@@ -52,12 +51,22 @@
     ) from caught_exc
 
 
-from google.auth import _helpers
-from google.auth import exceptions
-from google.auth import transport
+from google.auth import _helpers, exceptions, transport
 from google.auth.transport import _mtls_helper
 from google.oauth2 import service_account
 
+if TYPE_CHECKING:
+    try:
+        from urllib3._request_methods import RequestMethods as _HttpBase
+    except ImportError:
+        try:
+            from urllib3.request import RequestMethods as _HttpBase  # type: ignore
+        except ImportError:
+            _HttpBase = object  # type: ignore
+else:
+    _HttpBase = _helpers.HeapDummy
+
+
 # PEP 0810: Explicit Lazy Imports
 # Python 3.15+ natively intercepts and defers these imports.
 # Developers can disable this behavior and force eager imports.
@@ -199,9 +208,10 @@ def _make_mutual_tls_http(cert, key):
     Raises:
         google.auth.exceptions.MutualTLSChannelError: If the cert or key is invalid.
     """
-    import certifi
     import ssl
 
+    import certifi
+
     ctx = urllib3.util.ssl_.create_urllib3_context()
     ctx.load_verify_locations(cafile=certifi.where())