Post-processing would crash if there is no files to unpack

sabnzbd/filesystem.py

@@ -295,8 +295,10 @@ def sanitize_and_trim_path(path: str) -> str:
 def sanitize_files(folder: Optional[str] = None, filelist: Optional[List[str]] = None) -> List[str]:
     """Sanitize each file in the folder or list of filepaths, return list of new names"""
     logging.info("Checking if any resulting filenames need to be sanitized")
-    if not filelist:
+    if folder:
         filelist = listdir_full(folder)
+    else:
+        filelist = filelist or []
 
     # Loop over all the files
     output_filelist = []

tests/test_filesystem.py

@@ -258,6 +258,11 @@ class TestSanitizeFiles(ffs.TestCase):
         self.fs.path_separator = "\\"
         self.fs.is_windows_fs = True
 
+    def test_sanitize_files_input(self):
+        assert [] == filesystem.sanitize_files(folder=None)
+        assert [] == filesystem.sanitize_files(filelist=None)
+        assert [] == filesystem.sanitize_files(folder=None, filelist=None)
+
     @set_platform("win32")
     @set_config({"sanitize_safe": True})
     def test_sanitize_files(self):