[youtube:tab] Show alerts only from the final webpage

yt_dlp/extractor/youtube.py

@@ -3395,9 +3395,8 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
             self._extract_mix_playlist(playlist, playlist_id, data, webpage),
             playlist_id=playlist_id, playlist_title=title)
 
-    def _extract_alerts(self, data, expected=False):
+    @staticmethod
-
+    def _extract_alerts(data):
-        def _real_extract_alerts():
         for alert_dict in try_get(data, lambda x: x['alerts'], list) or []:
             if not isinstance(alert_dict, dict):
                 continue
@@ -3413,9 +3412,10 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
                 if message:
                     yield alert_type, message
 
+    def _report_alerts(self, alerts, expected=True):
         errors = []
         warnings = []
-        for alert_type, alert_message in _real_extract_alerts():
+        for alert_type, alert_message in alerts:
             if alert_type.lower() == 'error':
                 errors.append([alert_type, alert_message])
             else:
@@ -3426,6 +3426,9 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
         if errors:
             raise ExtractorError('YouTube said: %s' % errors[-1][1], expected=expected)
 
+    def _extract_and_report_alerts(self, data, *args, **kwargs):
+        return self._report_alerts(self._extract_alerts(data), *args, **kwargs)
+
     def _reload_with_unavailable_videos(self, item_id, data, webpage):
         """
         Get playlist with unavailable videos if the 'show unavailable videos' button exists.
@@ -3504,7 +3507,7 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
 
             else:
                 # Youtube may send alerts if there was an issue with the continuation page
-                self._extract_alerts(response, expected=False)
+                self._extract_and_report_alerts(response, expected=False)
                 if not check_get_keys or dict_get(response, check_get_keys):
                     break
                 # Youtube sometimes sends incomplete data
@@ -3532,9 +3535,10 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
                 url, item_id,
                 'Downloading webpage%s' % (' (retry #%d)' % count if count else ''))
             data = self._extract_yt_initial_data(item_id, webpage)
-            self._extract_alerts(data, expected=True)
             if data.get('contents') or data.get('currentVideoEndpoint'):
                 break
+            # Extract alerts here only when there is error
+            self._extract_and_report_alerts(data)
             if count >= retries:
                 raise ExtractorError(last_error)
         return webpage, data
@@ -3594,6 +3598,7 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
         # YouTube sometimes provides a button to reload playlist with unavailable videos.
         if 'no-youtube-unavailable-videos' not in compat_opts:
             data = self._reload_with_unavailable_videos(item_id, data, webpage) or data
+        self._extract_and_report_alerts(data)
 
         tabs = try_get(
             data, lambda x: x['contents']['twoColumnBrowseResultsRenderer']['tabs'], list)