DGS-23862 Fix URL joining in Python client (#2228)

* MINOR fix url construction

* Add tests

* update CHANGELOG

Author: rayokota

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Confluent Python Client for Apache Kafka - CHANGELOG
 
+## v2.xx.x
+
+### Fixes
+
+- Fix URL joining in Python client (#2228)
+
+
 ## v2.14.0 - 2026-04-01
 
 v2.14.0 is a feature release with the following features, fixes and enhancements:

src/confluent_kafka/schema_registry/_async/schema_registry_client.py

@@ -571,7 +571,11 @@ async def send_http_request(
         response = None
         for i in range(self.max_retries + 1):
             response = await self.session.request(
-                method, url="/".join([base_url, url]), headers=headers, content=body, params=query
+                method,
+                url="/".join([base_url.rstrip("/"), url.lstrip("/")]),
+                headers=headers,
+                content=body,
+                params=query,
             )
 
             if is_success(response.status_code):

src/confluent_kafka/schema_registry/_sync/schema_registry_client.py

@@ -568,7 +568,11 @@ def send_http_request(
         response = None
         for i in range(self.max_retries + 1):
             response = self.session.request(
-                method, url="/".join([base_url, url]), headers=headers, content=body, params=query
+                method,
+                url="/".join([base_url.rstrip("/"), url.lstrip("/")]),
+                headers=headers,
+                content=body,
+                params=query,
             )
 
             if is_success(response.status_code):

tests/schema_registry/_async/test_config.py

@@ -15,8 +15,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+import re
+from unittest.mock import AsyncMock
+
 import pytest
-from httpx import BasicAuth
+from httpx import BasicAuth, Response
 
 from confluent_kafka.schema_registry import AsyncSchemaRegistryClient
 from confluent_kafka.schema_registry.rules.encryption.encrypt_executor import FieldEncryptionExecutor
@@ -61,6 +64,18 @@ def test_config_url_trailing_slash():
     assert test_client._rest_client.base_urls == [TEST_URL]
 
 
+@pytest.mark.asyncio
+async def test_config_url_no_double_slash():
+    conf = {'url': 'http://SchemaRegistry:65534/'}
+    test_client = AsyncSchemaRegistryClient(conf)
+    mock_response = Response(200, json={'subject': 'test'})
+    test_client._rest_client.session.request = AsyncMock(return_value=mock_response)
+    await test_client._rest_client.send_request('/subjects', method='GET')
+    called_url = test_client._rest_client.session.request.call_args.kwargs['url']
+    # Ensure no double slashes exist beyond the scheme (http://)
+    assert '//' not in re.sub(r'^https?://', '', called_url)
+
+
 def test_config_ssl_key_no_certificate():
     conf = {'url': TEST_URL, 'ssl.key.location': '/ssl/keys/client'}
     with pytest.raises(

tests/schema_registry/_sync/test_config.py

@@ -15,8 +15,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+import re
+from unittest.mock import Mock
+
 import pytest
-from httpx import BasicAuth
+from httpx import BasicAuth, Response
 
 from confluent_kafka.schema_registry import SchemaRegistryClient
 from confluent_kafka.schema_registry.rules.encryption.encrypt_executor import FieldEncryptionExecutor
@@ -61,6 +64,18 @@ def test_config_url_trailing_slash():
     assert test_client._rest_client.base_urls == [TEST_URL]
 
 
+@pytest.mark.asyncio
+def test_config_url_no_double_slash():
+    conf = {'url': 'http://SchemaRegistry:65534/'}
+    test_client = SchemaRegistryClient(conf)
+    mock_response = Response(200, json={'subject': 'test'})
+    test_client._rest_client.session.request = Mock(return_value=mock_response)
+    test_client._rest_client.send_request('/subjects', method='GET')
+    called_url = test_client._rest_client.session.request.call_args.kwargs['url']
+    # Ensure no double slashes exist beyond the scheme (http://)
+    assert '//' not in re.sub(r'^https?://', '', called_url)
+
+
 def test_config_ssl_key_no_certificate():
     conf = {'url': TEST_URL, 'ssl.key.location': '/ssl/keys/client'}
     with pytest.raises(