[Misc] vllm CLI flags should be ordered for better user readability

FIX #10016

Signed-off-by: chaunceyjiang <[email protected]>

vllm/utils.py

@@ -1148,9 +1148,23 @@ def __call__(self, parser, namespace, values, option_string=None):
                              "Expected 'true' or 'false'.")
 
 
+class SortedHelpFormatter(argparse.HelpFormatter):
+    """SortedHelpFormatter that sorts arguments by their option strings."""
+
+    def add_arguments(self, actions):
+        actions = sorted(actions, key=lambda x: x.option_strings)
+        super(SortedHelpFormatter, self).add_arguments(actions)
+
+
 class FlexibleArgumentParser(argparse.ArgumentParser):
     """ArgumentParser that allows both underscore and dash in names."""
 
+    def __init__(self, *args, **kwargs):
+        # Set the default 'formatter_class' to SortedHelpFormatter
+        if 'formatter_class' not in kwargs:
+            kwargs['formatter_class'] = SortedHelpFormatter
+        super().__init__(*args, **kwargs)
+
     def parse_args(self, args=None, namespace=None):
         if args is None:
             args = sys.argv[1:]
@@ -1214,7 +1228,7 @@ def _pull_args_from_config(self, args: List[str]) -> List[str]:
         index = args.index('--config')
         if index == len(args) - 1:
             raise ValueError("No config file specified! \
-                             Please check your command-line arguments.")
+                             Please check your command-line arguments."                                                                       )
 
         file_path = args[index + 1]
 
@@ -1258,7 +1272,7 @@ def _load_config_file(self, file_path: str) -> List[str]:
         if extension not in ('yaml', 'yml'):
             raise ValueError(
                 "Config file must be of a yaml/yml type.\
-                              %s supplied", extension)
+                              %s supplied"                                          , extension)
 
         # only expecting a flat dictionary of atomic types
         processed_args: List[str] = []
@@ -1270,7 +1284,7 @@ def _load_config_file(self, file_path: str) -> List[str]:
         except Exception as ex:
             logger.error(
                 "Unable to read the config file at %s. \
-                Make sure path is correct", file_path)
+                Make sure path is correct"                                          , file_path)
             raise ex
 
         store_boolean_arguments = [