From c11485162bcbf6f517fd9225850a048fc5f7cec1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergey=20M=E2=80=A4?= <dstftw@gmail.com>
Date: Mon, 17 Sep 2018 22:13:39 +0700
Subject: [PATCH] [youtube] Don't pollute default query dict (closes #17593)

---
 youtube_dl/extractor/youtube.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 2fe074cb4..e80e36f98 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -259,7 +259,9 @@ class YoutubeBaseInfoExtractor(InfoExtractor):
         return True
 
     def _download_webpage_handle(self, *args, **kwargs):
-        kwargs.setdefault('query', {})['disable_polymer'] = 'true'
+        query = kwargs.get('query', {}).copy()
+        query['disable_polymer'] = 'true'
+        kwargs['query'] = query
         return super(YoutubeBaseInfoExtractor, self)._download_webpage_handle(
             *args, **compat_kwargs(kwargs))