[youtube:tab] Raise error on tab redirect (#2318)

Closes #2306
Authored by: krichbanana, coletdjnz

README.md

@@ -138,7 +138,7 @@ ### Differences in default behavior
 * The output of `-F` is listed in a new format. Use `--compat-options list-formats` to revert this
 * All *experiences* of a funimation episode are considered as a single video. This behavior breaks existing archives. Use `--compat-options seperate-video-versions` to extract information from only the default player
 * Youtube live chat (if available) is considered as a subtitle. Use `--sub-langs all,-live_chat` to download all subtitles except live chat. You can also use `--compat-options no-live-chat` to prevent live chat from downloading
-* Youtube channel URLs are automatically redirected to `/video`. Append a `/featured` to the URL to download only the videos in the home page. If the channel does not have a videos tab, we try to download the equivalent `UU` playlist instead. Also, `/live` URLs raise an error if there are no live videos instead of silently downloading the entire channel. You may use `--compat-options no-youtube-channel-redirect` to revert all these redirections
+* Youtube channel URLs are automatically redirected to `/video`. Append a `/featured` to the URL to download only the videos in the home page. If the channel does not have a videos tab, we try to download the equivalent `UU` playlist instead. For all other tabs, if the channel does not show the requested tab, an error will be raised. Also, `/live` URLs raise an error if there are no live videos instead of silently downloading the entire channel. You may use `--compat-options no-youtube-channel-redirect` to revert all these redirections
 * Unavailable videos are also listed for youtube playlists. Use `--compat-options no-youtube-unavailable-videos` to remove this
 * If `ffmpeg` is used as the downloader, the downloading and merging of formats happen in a single step when possible. Use `--compat-options no-direct-merge` to revert this
 * Thumbnail embedding in `mp4` is done with mutagen if possible. Use `--compat-options embed-thumbnail-atomicparsley` to force the use of AtomicParsley instead

yt_dlp/extractor/youtube.py

@@ -4864,7 +4864,7 @@ def _real_extract(self, url):
             info_dict['entries'] = self._smuggle_data(info_dict['entries'], smuggled_data)
         return info_dict
 
-    _URL_RE = re.compile(rf'(?P<pre>{_VALID_URL})(?(channel_type)(?P<tab>/\w+))?(?P<post>.*)$')
+    _URL_RE = re.compile(rf'(?P<pre>{_VALID_URL})(?(not_channel)|(?P<tab>/\w+))?(?P<post>.*)$')
 
     def __real_extract(self, url, smuggled_data):
         item_id = self._match_id(url)
@@ -4896,6 +4896,7 @@ def get_mobj(url):
                 elif mobj['channel_type'] == 'browse':  # Youtube music /browse/ should be changed to /channel/
                     pre = f'https://www.youtube.com/channel/{item_id}'
 
+        original_tab_name = tab
         if is_channel and not tab and 'no-youtube-channel-redirect' not in compat_opts:
             # Home URLs should redirect to /videos/
             redirect_warning = ('A channel/user page was given. All the channel\'s videos will be downloaded. '
@@ -4930,29 +4931,35 @@ def get_mobj(url):
         tabs = traverse_obj(data, ('contents', 'twoColumnBrowseResultsRenderer', 'tabs'), expected_type=list)
         if tabs:
             selected_tab = self._extract_selected_tab(tabs)
-            tab_name = selected_tab.get('title', '')
+            selected_tab_name = selected_tab.get('title', '').lower()
+            if selected_tab_name == 'home':
+                selected_tab_name = 'featured'
+            requested_tab_name = mobj['tab'][1:]
             if 'no-youtube-channel-redirect' not in compat_opts:
-                if mobj['tab'] == '/live':
+                if requested_tab_name == 'live':
                     # Live tab should have redirected to the video
                     raise ExtractorError('The channel is not currently live', expected=True)
-                if mobj['tab'] == '/videos' and tab_name.lower() != mobj['tab'][1:]:
+                if requested_tab_name not in ('', selected_tab_name):
-                    redirect_warning = f'The URL does not have a {mobj["tab"][1:]} tab'
+                    redirect_warning = f'The channel does not have a {requested_tab_name} tab'
-                    if not mobj['not_channel'] and item_id[:2] == 'UC':
+                    if not original_tab_name:
-                        # Topic channels don't have /videos. Use the equivalent playlist instead
+                        if item_id[:2] == 'UC':
-                        pl_id = f'UU{item_id[2:]}'
+                            # Topic channels don't have /videos. Use the equivalent playlist instead
-                        pl_url = f'https://www.youtube.com/playlist?list={pl_id}'
+                            pl_id = f'UU{item_id[2:]}'
-                        try:
+                            pl_url = f'https://www.youtube.com/playlist?list={pl_id}'
-                            data, ytcfg = self._extract_data(pl_url, pl_id, ytcfg=ytcfg, fatal=True)
+                            try:
-                        except ExtractorError:
+                                data, ytcfg = self._extract_data(pl_url, pl_id, ytcfg=ytcfg, fatal=True, webpage_fatal=True)
-                            redirect_warning += ' and the playlist redirect gave error'
+                            except ExtractorError:
-                        else:
+                                redirect_warning += ' and the playlist redirect gave error'
-                            item_id, url, tab_name = pl_id, pl_url, mobj['tab'][1:]
+                            else:
-                            redirect_warning += f'. Redirecting to playlist {pl_id} instead'
+                                item_id, url, selected_tab_name = pl_id, pl_url, requested_tab_name
-                    if tab_name.lower() != mobj['tab'][1:]:
+                                redirect_warning += f'. Redirecting to playlist {pl_id} instead'
-                        redirect_warning += f'. {tab_name} tab is being downloaded instead'
+                        if selected_tab_name and selected_tab_name != requested_tab_name:
+                            redirect_warning += f'. {selected_tab_name} tab is being downloaded instead'
+                    else:
+                        raise ExtractorError(redirect_warning, expected=True)
 
         if redirect_warning:
-            self.report_warning(redirect_warning)
+            self.to_screen(redirect_warning)
         self.write_debug(f'Final URL: {url}')
 
         # YouTube sometimes provides a button to reload playlist with unavailable videos.