Rely on inheritted _make_metric as much as possible (facebook#2718)

Summary:
Pull Request resolved: facebook#2718

Simplify code.  Also references to super should help deobscure where this gets called/

Reviewed By: sdaulton

Differential Revision: D61852855

fbshipit-source-id: 6dcef4e86e2d86ec9713ef56e9e29b7f72062aef

ax/service/utils/instantiation.py

@@ -8,6 +8,7 @@
 
 import enum
 from collections.abc import Sequence
+from copy import deepcopy
 from dataclasses import dataclass
 
 from logging import Logger
@@ -139,11 +140,12 @@ def _get_deserialized_metric_kwargs(
  ) -> dict[str, Any]:
  """Get metric kwargs from metric_definitions if available and deserialize
  if so. Deserialization is necessary because they were serialized on creation"""
- metric_kwargs = (metric_definitions or {}).get(name, {})
+ # deepcopy is used because of subsequent modifications to the dict
+ metric_kwargs = deepcopy((metric_definitions or {}).get(name, {}))
  metric_class = metric_kwargs.pop("metric_class", metric_class)
- metric_kwargs["name"] = name
+ # this is necessary before deserialization because name will be required
+ metric_kwargs["name"] = metric_kwargs.get("name", name)
  metric_kwargs = metric_class.deserialize_init_args(metric_kwargs)
- metric_kwargs.pop("name")
  return metric_kwargs
 
  @classmethod
@@ -160,15 +162,15 @@ def _make_metric(
  "Metric names cannot contain spaces when used with AxClient. Got "
  f"{name!r}."
  )
-
- return metric_class(
+ kwargs = cls._get_deserialized_metric_kwargs(
  name=name,
- lower_is_better=lower_is_better,
- **cls._get_deserialized_metric_kwargs(
- name=name,
- metric_definitions=metric_definitions,
- metric_class=metric_class,
- ),
+ metric_definitions=metric_definitions,
+ metric_class=metric_class,
+ )
+ # avoid conflict is lower_is_better is specified in kwargs
+ kwargs["lower_is_better"] = kwargs.get("lower_is_better", lower_is_better)
+ return metric_class(
+ **kwargs,
  )
 
  @staticmethod