Make Adapters' parse_value and Cache's request_cache more permissive (#8132)

Author: okhat

dspy/adapters/utils.py

@@ -147,9 +147,16 @@ def parse_value(value, annotation):
             candidate = ast.literal_eval(value)
         except (ValueError, SyntaxError):
             candidate = value
-
-    return TypeAdapter(annotation).validate_python(candidate)
-
+    
+    try:
+        return TypeAdapter(annotation).validate_python(candidate)
+    except pydantic.ValidationError as e:
+        # if the annotation is Optional[str], return just the string value
+        if annotation.__origin__ is Union and type(None) in get_args(annotation):
+            if len(get_args(annotation)) == 2 and str in get_args(annotation):
+                return str(candidate)
+            else:
+                raise e
 
 def get_annotation_name(annotation):
     origin = get_origin(annotation)

dspy/clients/cache.py

@@ -163,23 +163,40 @@ def load_memory_cache(self, filepath: str) -> None:
                 self.memory_cache = cloudpickle.load(f)
 
 
-def request_cache(cache_arg_name: Optional[str] = None, ignored_args_for_cache_key: Optional[list[str]] = None):
-    """Decorator for applying caching to a function based on the request argument.
+def request_cache(
+    cache_arg_name: Optional[str] = None,
+    ignored_args_for_cache_key: Optional[list[str]] = ["api_key", "api_base", "base_url"],
+    *,                              # everything after this is keyword-only
+    maxsize: Optional[int] = None,  # legacy / no-op
+):
+    """
+    Decorator for applying caching to a function based on the request argument.
 
     Args:
         cache_arg_name: The name of the argument that contains the request. If not provided, the entire kwargs is used
             as the request.
         ignored_args_for_cache_key: A list of arguments to ignore when computing the cache key from the request.
     """
 
+    # ---- Deprecation notice ----------------------------------------------
+    if maxsize is not None:
+        logger.warning(
+            "`maxsize` is deprecated and no longer does anything; "
+            "the cache is now handled internally by `dspy.cache`. "
+            "This parameter will be removed in a future release.",
+        )
+    # ----------------------------------------------------------------------
+
     def decorator(fn):
         @wraps(fn)
         def wrapper(*args, **kwargs):
             import dspy
 
             cache = dspy.cache
             original_ignored_args_for_cache_key = cache.ignored_args_for_cache_key
-            cache.ignored_args_for_cache_key = ignored_args_for_cache_key or []
+
+            # FIXME: Why is this mutating the global cache instead of passing an argument?
+            cache.ignored_args_for_cache_key = list(ignored_args_for_cache_key) or []
 
             # Use fully qualified function name for uniqueness
             fn_identifier = f"{fn.__module__}.{fn.__qualname__}"