Enum validator improvements (#9045)

pydantic/_internal/_std_types_schema.py

@@ -14,6 +14,7 @@
 from enum import Enum
 from functools import partial
 from ipaddress import IPv4Address, IPv4Interface, IPv4Network, IPv6Address, IPv6Interface, IPv6Network
+from operator import attrgetter
 from typing import Any, Callable, Iterable, TypeVar
 
 import typing_extensions
@@ -63,13 +64,13 @@ def get_enum_core_schema(enum_type: type[Enum], config: ConfigDict) -> CoreSchem
     description = None if not enum_type.__doc__ else inspect.cleandoc(enum_type.__doc__)
     if description == 'An enumeration.':  # This is the default value provided by enum.EnumMeta.__new__; don't use it
         description = None
-    updates = {'title': enum_type.__name__, 'description': description}
-    updates = {k: v for k, v in updates.items() if v is not None}
+    js_updates = {'title': enum_type.__name__, 'description': description}
+    js_updates = {k: v for k, v in js_updates.items() if v is not None}
 
     def get_json_schema(_, handler: GetJsonSchemaHandler) -> JsonSchemaValue:
         json_schema = handler(core_schema.literal_schema([x.value for x in cases], ref=enum_ref))
         original_schema = handler.resolve_ref_schema(json_schema)
-        update_json_schema(original_schema, updates)
+        update_json_schema(original_schema, js_updates)
         return json_schema
 
     if not cases:
@@ -90,47 +91,32 @@ def to_enum(input_value: Any, /) -> Enum:
         try:
             return enum_type(input_value)
         except ValueError:
-            # The type: ignore on the next line is to ignore the requirement of LiteralString
-            raise PydanticCustomError('enum', f'Input should be {expected}', {'expected': expected})  # type: ignore
+            raise PydanticCustomError('enum', 'Input should be {expected}', {'expected': expected})
 
-    strict_python_schema = core_schema.is_instance_schema(enum_type)
-
-    to_enum_validator = core_schema.no_info_plain_validator_function(to_enum)
     if issubclass(enum_type, int):
         # this handles `IntEnum`, and also `Foobar(int, Enum)`
-        updates['type'] = 'integer'
-        lax = core_schema.chain_schema([core_schema.int_schema(), to_enum_validator])
-        # Disallow float from JSON due to strict mode
-        strict = core_schema.json_or_python_schema(
-            json_schema=core_schema.no_info_after_validator_function(to_enum, core_schema.int_schema()),
-            python_schema=strict_python_schema,
-        )
+        js_updates['type'] = 'integer'
+        lax_schema = core_schema.no_info_after_validator_function(to_enum, core_schema.int_schema())
     elif issubclass(enum_type, str):
         # this handles `StrEnum` (3.11 only), and also `Foobar(str, Enum)`
-        updates['type'] = 'string'
-        lax = core_schema.chain_schema([core_schema.str_schema(), to_enum_validator])
-        strict = core_schema.json_or_python_schema(
-            json_schema=core_schema.no_info_after_validator_function(to_enum, core_schema.str_schema()),
-            python_schema=strict_python_schema,
-        )
+        js_updates['type'] = 'string'
+        lax_schema = core_schema.no_info_after_validator_function(to_enum, core_schema.str_schema())
     elif issubclass(enum_type, float):
-        updates['type'] = 'numeric'
-        lax = core_schema.chain_schema([core_schema.float_schema(), to_enum_validator])
-        strict = core_schema.json_or_python_schema(
-            json_schema=core_schema.no_info_after_validator_function(to_enum, core_schema.float_schema()),
-            python_schema=strict_python_schema,
-        )
+        js_updates['type'] = 'numeric'
+        lax_schema = core_schema.no_info_after_validator_function(to_enum, core_schema.float_schema())
     else:
-        lax = to_enum_validator
-        strict = core_schema.json_or_python_schema(json_schema=to_enum_validator, python_schema=strict_python_schema)
+        lax_schema = core_schema.no_info_plain_validator_function(to_enum)
+
     enum_schema = core_schema.lax_or_strict_schema(
-        lax_schema=lax, strict_schema=strict, ref=enum_ref, metadata={'pydantic_js_functions': [get_json_schema]}
+        lax_schema=lax_schema,
+        strict_schema=core_schema.json_or_python_schema(
+            json_schema=lax_schema, python_schema=core_schema.is_instance_schema(enum_type)
+        ),
+        ref=enum_ref,
+        metadata={'pydantic_js_functions': [get_json_schema]},
     )
-    use_enum_values = config.get('use_enum_values', False)
-    if use_enum_values:
-        enum_schema = core_schema.chain_schema(
-            [enum_schema, core_schema.no_info_plain_validator_function(lambda x: x.value)]
-        )
+    if config.get('use_enum_values', False):
+        enum_schema = core_schema.no_info_after_validator_function(attrgetter('value'), enum_schema)
 
     return enum_schema