From a89906699c61362e51e09914f0ed467270e9b4a6 Mon Sep 17 00:00:00 2001
From: Elaina <GreyElaina@outlook.com>
Date: Tue, 3 Dec 2024 01:21:59 +0800
Subject: [PATCH] fix: merge existing params in url, close #3433

---
 httpx/_models.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/httpx/_models.py b/httpx/_models.py
index 67d74bf86b..04ef71e277 100644
--- a/httpx/_models.py
+++ b/httpx/_models.py
@@ -396,7 +396,9 @@ def __init__(
         extensions: RequestExtensions | None = None,
     ) -> None:
         self.method = method.upper()
-        self.url = URL(url) if params is None else URL(url, params=params)
+        self.url = URL(url)
+        if params is not None:
+            self.url = self.url.copy_merge_params(params=params)
         self.headers = Headers(headers)
         self.extensions = {} if extensions is None else dict(extensions)