fix: Do not use ADC if passing a base_url, no project, no location

PiperOrigin-RevId: 832020600

Author: sasha-gitg

google/genai/_api_client.py

@@ -628,15 +628,15 @@ def __init__(
         )
         self.api_key = None
 
-      if not self.location and not self.api_key:
-          self.location = 'global'
-
       self.custom_base_url = (
           validated_http_options.base_url
           if validated_http_options.base_url
           else None
       )
 
+      if not self.location and not self.api_key and not self.custom_base_url:
+          self.location = 'global'
+
       # Skip fetching project from ADC if base url is provided in http options.
       if (
           not self.project

google/genai/tests/client/test_client_initialization.py

@@ -372,7 +372,8 @@ def mock_auth_default(scopes=None):
   monkeypatch.setattr(google.auth, "default", mock_auth_default)
   # Including a base_url override skips the check for having proj/location or
   # api_key set.
-  Client(vertexai=True, http_options={"base_url": "https://override.com/"})
+  client = Client(vertexai=True, http_options={"base_url": "https://override.com/"})
+  assert client.models._api_client.location is None
 
 
 def test_invalid_mldev_constructor_empty(monkeypatch):