serialize callable functions in config (#1367)

lm_eval/api/task.py

@@ -5,6 +5,7 @@ import random
 import re
 from collections.abc import Callable
 from dataclasses import asdict, dataclass
+from inspect import getsource
 from typing import Any, List, Literal, Tuple, Union
 
 import datasets
@@ -37,7 +38,6 @@ ALL_OUTPUT_TYPES = [
     "generate_until",
 ]
 
-
 eval_logger = logging.getLogger("lm-eval")
 
 
@@ -110,15 +110,13 @@ class TaskConfig(dict):
                     "do_sample": False,
                 }
 
-        # TODO: how to make TaskConfigs be de- and re-serializable, even when using the !function constructor?
-
     def __getitem__(self, item):
         return getattr(self, item)
 
     def __setitem__(self, item, value):
         return setattr(self, item, value)
 
-    def to_dict(self, keep_callable=False):
+    def to_dict(self, keep_callable: bool = False) -> dict:
         """dumps the current config as a dictionary object, as a printable format.
         null fields will not be printed.
         Used for dumping results alongside full task configuration
@@ -133,14 +131,34 @@ class TaskConfig(dict):
         for k, v in list(cfg_dict.items()):
             if v is None:
                 cfg_dict.pop(k)
-            elif isinstance(v, Callable):
-                if keep_callable:
+            elif k == "metric_list":
+                for metric_dict in v:
+                    for metric_key, metric_value in metric_dict.items():
+                        if callable(metric_value):
+                            metric_dict[metric_key] = self.serialize_function(
+                                metric_value, keep_callable=keep_callable
+                            )
                 cfg_dict[k] = v
-                else:
-                    # TODO: this should handle Promptsource template objects as a separate case?
-                    cfg_dict[k] = str(v)
+            elif callable(v):
+                cfg_dict[k] = self.serialize_function(v, keep_callable=keep_callable)
         return cfg_dict
 
+    def serialize_function(
+        self, value: Union[Callable, str], keep_callable=False
+    ) -> Union[Callable, str]:
+        """Serializes a given function or string.
+
+        If 'keep_callable' is True, the original callable is returned.
+        Otherwise, attempts to return the source code of the callable using 'getsource'.
+        """
+        if keep_callable:
+            return value
+        else:
+            try:
+                return getsource(value)
+            except (TypeError, OSError):
+                return str(value)
+
 
 class Task(abc.ABC):
     """A task represents an entire benchmark including its dataset, problems,