Improve `extractor_args` parsing

5 files changed, 29 insertions, 15 deletions

diff --git a/Changelog.md b/Changelog.md
index 8eebff95e..d8e818b65 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -22,9 +22,9 @@
 ### 2021.07.07
 
 * Merge youtube-dl: Upto [commit/a803582](https://github.com/ytdl-org/youtube-dl/commit/a8035827177d6b59aca03bd717acb6a9bdd75ada)
-* Add `--extractor-args` to pass extractor-specific arguments
+* Add `--extractor-args` to pass some extractor-specific arguments. See [readme](https://github.com/yt-dlp/yt-dlp#extractor-arguments)
     * Add extractor option `skip` for `youtube`. Eg: `--extractor-args youtube:skip=hls,dash`
-    * Deprecates --youtube-skip-dash-manifest, --youtube-skip-hls-manifest, --youtube-include-dash-manifest, --youtube-include-hls-manifest
+    * Deprecates `--youtube-skip-dash-manifest`, `--youtube-skip-hls-manifest`, `--youtube-include-dash-manifest`, `--youtube-include-hls-manifest`
 * Allow `--list...` options to work with `--print`, `--quiet` and other `--list...` options
 * [youtube] Use `player` API for additional video extraction requests by [colethedj](https://github.com/colethedj)
     * **Fixes youtube premium music** (format 141) extraction
diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index 17d2e7158..07f413733 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -3498,9 +3498,18 @@ class InfoExtractor(object):
             else 'public' if all_known
             else None)
 
-    def _configuration_arg(self, key):
-        return traverse_obj(
+    def _configuration_arg(self, key, default=NO_DEFAULT, casesense=False):
+        '''
+        @returns            A list of values for the extractor argument given by "key"
+                            or "default" if no such key is present
+        @param default      The default value to return when the key is not present (default: [])
+        @param casesense    When false, the values are converted to lower case
+        '''
+        val = traverse_obj(
             self._downloader.params, ('extractor_args', self.ie_key().lower(), key))
+        if val is None:
+            return [] if default is NO_DEFAULT else default
+        return list(val) if casesense else [x.lower() for x in val]
 
 
 class SearchInfoExtractor(InfoExtractor):
diff --git a/yt_dlp/extractor/funimation.py b/yt_dlp/extractor/funimation.py
index 4690c5234..4c61d126b 100644
--- a/yt_dlp/extractor/funimation.py
+++ b/yt_dlp/extractor/funimation.py
@@ -186,8 +186,8 @@ class FunimationIE(InfoExtractor):
         for lang, version, fmt in self._get_experiences(episode):
             experience_id = str(fmt['experienceId'])
             if (only_initial_experience and experience_id != initial_experience_id
-                    or requested_languages and lang not in requested_languages
-                    or requested_versions and version not in requested_versions):
+                    or requested_languages and lang.lower() not in requested_languages
+                    or requested_versions and version.lower() not in requested_versions):
                 continue
             thumbnails.append({'url': fmt.get('poster')})
             duration = max(duration, fmt.get('duration', 0))
diff --git a/yt_dlp/extractor/youtube.py b/yt_dlp/extractor/youtube.py
index 1233cc399..de70fcdd3 100644
--- a/yt_dlp/extractor/youtube.py
+++ b/yt_dlp/extractor/youtube.py
@@ -2207,11 +2207,11 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
 
         player_url = self._extract_player_url(ytcfg, webpage)
 
-        player_client = try_get(self._configuration_arg('player_client'), lambda x: x[0], str) or ''
-        if player_client.upper() not in ('WEB', 'ANDROID'):
-            player_client = 'WEB'
-        force_mobile_client = player_client.upper() == 'ANDROID'
-        player_skip = self._configuration_arg('player_skip') or []
+        player_client = (self._configuration_arg('player_client') or [''])[0]
+        if player_client not in ('web', 'android', ''):
+            self.report_warning(f'Invalid player_client {player_client} given. Falling back to WEB')
+        force_mobile_client = player_client == 'android'
+        player_skip = self._configuration_arg('player_skip')
 
         def get_text(x):
             if not x:
@@ -2489,7 +2489,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                     dct['container'] = dct['ext'] + '_dash'
             formats.append(dct)
 
-        skip_manifests = self._configuration_arg('skip') or []
+        skip_manifests = self._configuration_arg('skip')
         get_dash = 'dash' not in skip_manifests and self.get_param('youtube_include_dash_manifest', True)
         get_hls = 'hls' not in skip_manifests and self.get_param('youtube_include_hls_manifest', True)
 
diff --git a/yt_dlp/options.py b/yt_dlp/options.py
index 5caf4cb53..64bc380e1 100644
--- a/yt_dlp/options.py
+++ b/yt_dlp/options.py
@@ -137,7 +137,11 @@ def parseOpts(overrideArguments=None):
         else:
             raise optparse.OptionValueError(
                 'wrong %s formatting; it should be %s, not "%s"' % (opt_str, option.metavar, value))
-        val = process(val) if callable(process) else val
+        try:
+            val = process(val) if process else val
+        except Exception as err:
+            raise optparse.OptionValueError(
+                'wrong %s formatting; %s' % (opt_str, err))
         for key in keys:
             out_dict[key] = val
 
@@ -1344,6 +1348,7 @@ def parseOpts(overrideArguments=None):
         '--no-hls-split-discontinuity',
         dest='hls_split_discontinuity', action='store_false',
         help='Do not split HLS playlists to different formats at discontinuities such as ad breaks (default)')
+    _extractor_arg_parser = lambda key, vals='': (key.strip().lower(), [val.strip() for val in vals.split(',')])
     extractor.add_option(
         '--extractor-args',
         metavar='KEY:ARGS', dest='extractor_args', default={}, type='str',
@@ -1351,11 +1356,11 @@ def parseOpts(overrideArguments=None):
         callback_kwargs={
             'multiple_keys': False,
             'process': lambda val: dict(
-                (lambda x: (x[0], x[1].split(',')))(arg.split('=', 1) + ['', '']) for arg in val.split(';'))
+                _extractor_arg_parser(*arg.split('=', 1)) for arg in val.split(';'))
         },
         help=(
             'Pass these arguments to the extractor. See "EXTRACTOR ARGUMENTS" for details. '
-            'You can use this option multiple times to give different arguments to different extractors'))
+            'You can use this option multiple times to give arguments for different extractors'))
     extractor.add_option(
         '--youtube-include-dash-manifest', '--no-youtube-skip-dash-manifest',
         action='store_true', dest='youtube_include_dash_manifest', default=True,