[YouTube] Fix KeyError QV in signature extraction failed

* temporarily force missing global definition into sig JS
* improve test: thanks https://github.com/yt-dlp/yt-dlp/issues/7327#issuecomment-1595274615
* resolves #32314

test/test_youtube_signature.py

@@ -63,6 +63,11 @@ _SIG_TESTS = [
         'https://s.ytimg.com/yts/jsbin/html5player-en_US-vflKjOTVq/html5player.js',
         '312AA52209E3623129A412D56A40F11CB0AF14AE.3EE09501CB14E3BCDC3B2AE808BF3F1D14E7FBF12',
         '112AA5220913623229A412D56A40F11CB0AF14AE.3EE0950FCB14EEBCDC3B2AE808BF331D14E7FBF3',
+    ),
+    (
+        'https://www.youtube.com/s/player/6ed0d907/player_ias.vflset/en_US/base.js',
+        '2aq0aqSyOoJXtK73m-uME_jv7-pT15gOFC02RFkGMqWpzEICs69VdbwQ0LDp1v7j8xx92efCJlYFYb1sUkkBSPOlPmXgIARw8JQ0qOAOAA',
+        'AOq0QJ8wRAIgXmPlOPSBkkUs1bYFYlJCfe29xx8j7v1pDL2QwbdV96sCIEzpWqMGkFR20CFOg51Tp-7vj_EMu-m37KtXJoOySqa0',
     )
 ]
 
@@ -231,7 +236,7 @@ def n_sig(jscode, sig_input):
 
 
 make_sig_test = t_factory(
-    'signature', signature, re.compile(r'.*-(?P<id>[a-zA-Z0-9_-]+)(?:/watch_as3|/html5player)?\.[a-z]+$'))
+    'signature', signature, re.compile(r'(?s).*(?:-|/player/)(?P<id>[a-zA-Z0-9_-]+)(?:/.+\.js|(?:/watch_as3|/html5player)?\.[a-z]+)$'))
 for test_spec in _SIG_TESTS:
     make_sig_test(*test_spec)
 

youtube_dl/extractor/youtube.py

@@ -1569,8 +1569,12 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
              r'\bc\s*&&\s*[a-zA-Z0-9]+\.set\([^,]+\s*,\s*\([^)]*\)\s*\(\s*(?P<sig>[a-zA-Z0-9$]+)\('),
             jscode, 'Initial JS player signature function name', group='sig')
 
-        jsi = JSInterpreter(jscode)
+        # temporary (please) hack for player 6ed0d907 #32314
+        ah = 'var AH={LR:function(a,b){var c=a[0];a[0]=a[b%a.length];a[b%a.length]=c},QV:function(a){a.reverse()},pO:function(a,b){a.splice(0,b)}};'
+        jsi = JSInterpreter(ah + jscode)
+
         initial_function = jsi.extract_function(funcname)
+
         return lambda s: initial_function([s])
 
     def _decrypt_signature(self, s, video_id, player_url):

youtube_dl/jsinterp.py

@@ -941,15 +941,15 @@ class JSInterpreter(object):
         _FUNC_NAME_RE = r'''(?:[a-zA-Z$0-9]+|"[a-zA-Z$0-9]+"|'[a-zA-Z$0-9]+')'''
         obj = {}
         obj_m = re.search(
-            r'''(?x)
-                (?<!this\.)%s\s*=\s*{\s*
-                    (?P<fields>(%s\s*:\s*function\s*\(.*?\)\s*{.*?}(?:,\s*)?)*)
-                }\s*;
-            ''' % (re.escape(objname), _FUNC_NAME_RE),
+            r'''(?xs)
+                (?:{0}\s*\.\s*{1}|{1}\s*=\s*\{{\s*
+                    (?P<fields>({2}\s*:\s*function\s*\(.*?\)\s*\{{.*?}}(?:,\s*)?)*)
+                }}\s*);
+            '''.format(_NAME_RE, re.escape(objname), _FUNC_NAME_RE),
             self.code)
-        if not obj_m:
+        fields = obj_m and obj_m.group('fields')
+        if fields is None:
             raise self.Exception('Could not find object ' + objname)
-        fields = obj_m.group('fields')
         # Currently, it only supports function definitions
         fields_m = re.finditer(
             r'''(?x)
@@ -985,9 +985,9 @@ class JSInterpreter(object):
                 \((?P<args>[^)]*)\)\s*
                 (?P<code>{.+})''' % {'name': re.escape(funcname)},
             self.code)
-        code, _ = self._separate_at_paren(func_m.group('code'))  # refine the match
         if func_m is None:
             raise self.Exception('Could not find JS function "{funcname}"'.format(**locals()))
+        code, _ = self._separate_at_paren(func_m.group('code'))  # refine the match
         return self.build_arglist(func_m.group('args')), code
 
     def extract_function(self, funcname):