RESTClient: fix duplicate params in URL in JSONResponsePaginator

dlt/sources/helpers/rest_client/paginators.py

@@ -420,6 +420,10 @@ def update_request(self, request: Request) -> None:
 
         request.url = self._next_reference
 
+        # Clear the query parameters from the previous request otherwise they
+        # will be appended to the next URL in Session.prepare_request
+        request.params = None
+
 
 class HeaderLinkPaginator(BaseNextUrlPaginator):
     """A paginator that uses the 'Link' header in HTTP responses

tests/sources/helpers/rest_client/test_paginators.py

@@ -3,6 +3,7 @@
 import pytest
 
 from requests.models import Response, Request
+from requests import Session
 
 from dlt.sources.helpers.rest_client.paginators import (
     SinglePagePaginator,
@@ -157,6 +158,30 @@ def test_update_request(self, test_case):
         paginator.update_request(request)
         assert request.url == test_case["expected"]
 
+    def test_no_duplicate_params_on_update_request(self):
+        paginator = JSONResponsePaginator()
+
+        request = Request(
+            method="GET",
+            url="http://example.com/api/resource",
+            params={"param1": "value1"},
+        )
+
+        session = Session()
+
+        response = Mock(Response, json=lambda: {"next": "/api/resource?page=2&param1=value1"})
+        paginator.update_state(response)
+        paginator.update_request(request)
+
+        assert request.url == "http://example.com/api/resource?page=2&param1=value1"
+
+        # RESTClient._send_request() calls Session.prepare_request() which
+        # updates the URL with the query parameters from the request object.
+        prepared_request = session.prepare_request(request)
+
+        # The next request should just use the "next" URL without any duplicate parameters.
+        assert prepared_request.url == "http://example.com/api/resource?page=2&param1=value1"
+
 
 class TestSinglePagePaginator:
     def test_update_state(self):