Standardise get_rope to use rope_parameters["partial_rotary_factor"], not rotary_dim (#30389)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

vllm/config/utils.py

@@ -73,14 +73,28 @@ def get_field(cls: ConfigType, name: str) -> Field:
     )
 
 
-def getattr_iter(object: object, names: Iterable[str], default: Any) -> Any:
+def getattr_iter(
+    object: object, names: Iterable[str], default: Any, warn: bool = False
+) -> Any:
     """
     A helper function that retrieves an attribute from an object which may
     have multiple possible names. This is useful when fetching attributes from
     arbitrary `transformers.PretrainedConfig` instances.
+
+    In the case where the first name in `names` is the preferred name, and
+    any other names are deprecated aliases, setting `warn=True` will log a
+    warning when a deprecated name is used.
     """
-    for name in names:
+    for i, name in enumerate(names):
         if hasattr(object, name):
+            if warn and i > 0:
+                logger.warning_once(
+                    "%s contains a deprecated attribute name '%s'. "
+                    "Please use the preferred attribute name '%s' instead.",
+                    type(object).__name__,
+                    name,
+                    names[0],
+                )
             return getattr(object, name)
     return default