wip

- Fix: Conditional chat_template_stage construction in legacy coercion
- The logic unconditionally set `chat_template_stage`  to a default dict
even when no legacy fields were present. This bypassed the Field default.
- Now it only constructs the stage config if legacy fields  are actually detected.

Signed-off-by: Nikhil Ghosh <nikhil@anyscale.com>

Author: nrghosh

python/ray/llm/_internal/batch/processor/base.py

@@ -210,12 +210,12 @@ def _coerce_legacy_to_stage_config(cls, values: Dict[str, Any]) -> Dict[str, Any
                     "or `chat_template_stage={'enabled': True, 'chat_template': '...'}`. "
                     "This will raise an error in a future version."
                 )
-            enabled_value = values.get("apply_chat_template")
-            enabled = enabled_value if enabled_value is not None else True
-            stage: Dict[str, Any] = {"enabled": enabled}
-            if values.get("chat_template") is not None:
-                stage["chat_template"] = values["chat_template"]
-            values["chat_template_stage"] = stage
+                enabled_value = values.get("apply_chat_template")
+                enabled = enabled_value if enabled_value is not None else True
+                stage: Dict[str, Any] = {"enabled": enabled}
+                if values.get("chat_template") is not None:
+                    stage["chat_template"] = values["chat_template"]
+                values["chat_template_stage"] = stage
 
         # Other stages: simple boolean-to-stage mapping
         stage_mappings = [