Handle default in switch better

Add https://github.com/yt-dlp/yt-dlp/commit/a1fc7ca0743c8df06416e68ee74b64e07dfe7135
Thanks coletdjnz

test/test_jsinterp.py

@@ -133,6 +133,21 @@ class TestJSInterpreter(unittest.TestCase):
         self.assertEqual(jsi.call_function('x', 3), 6)
         self.assertEqual(jsi.call_function('x', 5), 0)
 
+    def test_switch_default(self):
+        jsi = JSInterpreter('''
+        function x(f) { switch(f){
+            case 2: f+=2;
+            default: f-=1;
+            case 5:
+            case 6: f+=6;
+            case 0: break;
+            case 1: f+=1;
+        } return f }
+        ''')
+        self.assertEqual(jsi.call_function('x', 1), 2)
+        self.assertEqual(jsi.call_function('x', 5), 11)
+        self.assertEqual(jsi.call_function('x', 9), 14)
+
     def test_try(self):
         jsi = JSInterpreter('''
         function x() { try{return 10} catch(e){return 5} }

youtube_dl/jsinterp.py

@@ -240,21 +240,26 @@ class JSInterpreter(object):
             switch_val, remaining = self._separate_at_paren(expr[m.end() - 1:], ')')
             switch_val = self.interpret_expression(switch_val, local_vars, allow_recursion)
             body, expr = self._separate_at_paren(remaining, '}')
-            body, default = body.split('default:') if 'default:' in body else (body, None)
-            items = body.split('case ')[1:]
-            if default:
-                items.append('default:%s' % (default, ))
-            matched = False
-            for item in items:
-                case, stmt = [i.strip() for i in self._separate(item, ':', 1)]
-                matched = matched or case == 'default' or switch_val == self.interpret_expression(case, local_vars, allow_recursion)
-                if matched:
+            items = body.replace('default:', 'case default:').split('case ')[1:]
+            for default in (False, True):
+                matched = False
+                for item in items:
+                    case, stmt = [i.strip() for i in self._separate(item, ':', 1)]
+                    if default:
+                        matched = matched or case == 'default'
+                    elif not matched:
+                        matched = (case != 'default'
+                                   and switch_val == self.interpret_expression(case, local_vars, allow_recursion))
+                    if not matched:
+                        continue
                     try:
                         ret, should_abort = self.interpret_statement(stmt, local_vars, allow_recursion - 1)
                         if should_abort:
                             return ret
                     except JS_Break:
                         break
+                if matched:
+                    break
             return self.interpret_statement(expr, local_vars, allow_recursion - 1)[0]
 
         # Comma separated statements