Fix (dis)like, music list extraction due to YouTube changes (again)

YouTube reverted the changes they made that prompted f9f5d5ba.

In case they change their minds again, this adds support for both
formats.

The liberal_update and conservative_update functions needed to be
modified to handle the cases of empty lists, so that
a successfully extracted 'music_list': [{'Author':...},...] will
not be overwritten by 'music_list': [] in the calls to
liberal_dict_update.

Signed-off-by: Jesús <heckyel@hyperbola.info>

youtube/yt_data_extract/watch_extraction.py

@@ -2,7 +2,8 @@ from .common import (get, multi_get, deep_get, multi_deep_get,
     liberal_update, conservative_update, remove_redirect, normalize_url,
     extract_str, extract_formatted_text, extract_int, extract_approx_int,
     extract_date, check_missing_keys, extract_item_info, extract_items,
-    extract_response, concat_or_none)
+    extract_response, concat_or_none, liberal_dict_update,
+    conservative_dict_update)
 
 import json
 import urllib.parse
@@ -211,13 +212,33 @@ def _extract_metadata_row_info(renderer_content):
 
     return info
 
+def _extract_from_video_metadata(renderer_content):
+    info = _extract_from_video_information_renderer(renderer_content)
+    liberal_dict_update(info, _extract_likes_dislikes(renderer_content))
+    liberal_dict_update(info, _extract_from_owner_renderer(renderer_content))
+    liberal_dict_update(info, _extract_metadata_row_info(deep_get(
+        renderer_content, 'metadataRowContainer',
+        'metadataRowContainerRenderer', default={}
+    )))
+    liberal_update(info, 'title', extract_str(renderer_content.get('title')))
+    liberal_update(
+        info, 'description',
+        extract_str(renderer_content.get('description'), recover_urls=True)
+    )
+    liberal_update(info, 'time_published',
+                   extract_date(renderer_content.get('dateText')))
+    return info
+
 visible_extraction_dispatch = {
+    # Either these ones spread around in various places
     'slimVideoInformationRenderer': _extract_from_video_information_renderer,
     'slimVideoActionBarRenderer': _extract_likes_dislikes,
     'slimOwnerRenderer': _extract_from_owner_renderer,
     'videoDescriptionHeaderRenderer': _extract_from_video_header_renderer,
     'expandableVideoDescriptionRenderer': _extract_from_description_renderer,
     'metadataRowContainerRenderer': _extract_metadata_row_info,
+    # OR just this one, which contains SOME of the above inside it
+    'slimVideoMetadataRenderer': _extract_from_video_metadata,
 }
 
 def _extract_watch_info_mobile(top_level):
@@ -265,12 +286,14 @@ def _extract_watch_info_mobile(top_level):
     for renderer in items:
         name, renderer_content = list(renderer.items())[0]
         found.add(name)
-        info.update(visible_extraction_dispatch[name](renderer_content))
+        liberal_dict_update(
+            info,
+            visible_extraction_dispatch[name](renderer_content)
+        )
     # Call the function on blank dict for any that weren't found
     # so that the empty keys get added
     for name in visible_extraction_dispatch.keys() - found:
-        info.update(visible_extraction_dispatch[name]({}))
-
+        liberal_dict_update(info, visible_extraction_dispatch[name]({}))
 
     # comment section info
     items, _ = extract_items(response, item_types={