fix(client): preserve hardcoded query params when merging with user params

Author: dtmeadows

src/anthropic/_base_client.py

@@ -553,6 +553,12 @@ def _build_request(
                 files = cast(HttpxRequestFiles, ForceMultipartDict())
 
         prepared_url = self._prepare_url(options.url)
+        # When the URL contains hardcoded query params (e.g. ?beta=true) and
+        # additional params are provided, httpx will replace the URL's query
+        # string with the params. Merge them to preserve both.
+        if params and prepared_url.query:
+            params = {**dict(prepared_url.params.items()), **params}
+            prepared_url = prepared_url.copy_with(raw_path=prepared_url.path.encode())
         if "_" in prepared_url.host:
             # work around https://github.com/encode/httpx/discussions/2880
             kwargs["extensions"] = {"sni_hostname": prepared_url.host.replace("_", "-")}

tests/test_client.py

@@ -453,6 +453,22 @@ def test_default_query_option(self) -> None:
 
         client.close()
 
+    def test_hardcoded_query_params_in_url(self, client: Anthropic) -> None:
+        request = client._build_request(FinalRequestOptions(method="get", url="/foo?beta=true"))
+        url = httpx.URL(request.url)
+        assert dict(url.params) == {"beta": "true"}
+
+    def test_hardcoded_query_params_with_extra_params(self, client: Anthropic) -> None:
+        request = client._build_request(
+            FinalRequestOptions(
+                method="get",
+                url="/foo?beta=true",
+                params={"limit": "10", "page": "abc"},
+            )
+        )
+        url = httpx.URL(request.url)
+        assert dict(url.params) == {"beta": "true", "limit": "10", "page": "abc"}
+
     def test_request_extra_json(self, client: Anthropic) -> None:
         request = client._build_request(
             FinalRequestOptions(
@@ -1458,6 +1474,22 @@ async def test_default_query_option(self) -> None:
 
         await client.close()
 
+    def test_hardcoded_query_params_in_url(self, async_client: AsyncAnthropic) -> None:
+        request = async_client._build_request(FinalRequestOptions(method="get", url="/foo?beta=true"))
+        url = httpx.URL(request.url)
+        assert dict(url.params) == {"beta": "true"}
+
+    def test_hardcoded_query_params_with_extra_params(self, async_client: AsyncAnthropic) -> None:
+        request = async_client._build_request(
+            FinalRequestOptions(
+                method="get",
+                url="/foo?beta=true",
+                params={"limit": "10", "page": "abc"},
+            )
+        )
+        url = httpx.URL(request.url)
+        assert dict(url.params) == {"beta": "true", "limit": "10", "page": "abc"}
+
     def test_request_extra_json(self, client: Anthropic) -> None:
         request = client._build_request(
             FinalRequestOptions(