Fix allow-unsafe-ext compat option (#16920)

Fix bug in e578e265f7

Closes #16919
Authored by: bashonly

yt_dlp/__init__.py

@@ -619,7 +619,7 @@ def validate_options(opts):
         warnings.append(
             'Using allow-unsafe-ext opens you up to potential attacks. '
             'Use with great care!')
-        _UnsafeExtensionError.sanitize_extension = lambda x, prepend=False: x
+        _UnsafeExtensionError._enabled = False
 
     return warnings, deprecation_warnings
 

yt_dlp/utils/_utils.py

@@ -5218,12 +5218,17 @@ class _UnsafeExtensionError(Exception):
         'sbv',
     ])
 
+    _enabled = True
+
     def __init__(self, extension, /):
         super().__init__(f'unsafe file extension: {extension!r}')
         self.extension = extension
 
     @classmethod
     def sanitize_extension(cls, extension, /, *, prepend=False, _allowed_exts=()):
+        if not cls._enabled:
+            return extension
+
         if extension is None:
             return None