[ConfigArgumentMerger] Improve ConfigArgumentMerger compatibility with external callers (#17051)

python/sglang/srt/server_args_config_parser.py

@@ -16,9 +16,14 @@ logger = logging.getLogger(__name__)
 class ConfigArgumentMerger:
     """Handles merging of configuration file arguments with command-line arguments."""
 
-    def __init__(self, parser: argparse.ArgumentParser):
+    def __init__(
+        self,
+        parser: argparse.ArgumentParser = None,
+        boolean_actions: List[str] = None,
+    ):
         """Initialize with list of store_true action names."""
         # NOTE: The current code does not support actions other than "store_true" and "store".
+        if parser is not None:
             self.parser = parser
             self.store_true_actions = [
                 action.dest
@@ -35,6 +40,13 @@ class ConfigArgumentMerger:
                 and "--help" not in a.option_strings
                 and "-h" not in a.option_strings
             }
+        elif boolean_actions is not None:
+            # Legacy interface for compatibility
+            self.store_true_actions = boolean_actions
+            self.unsupported_actions = {}
+        else:
+            self.store_true_actions = []
+            self.unsupported_actions = {}
 
     def merge_config_with_args(self, cli_args: List[str]) -> List[str]:
         """