Fix length validation error on Enum fields

src/marshmallow_sqlalchemy/convert.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import enum
 import functools
 import inspect
 import uuid
@@ -435,16 +436,19 @@ def _add_column_kwargs(self, kwargs: dict[str, Any], column: sa.Column) -> None:
             kwargs["validate"].append(validate.OneOf(choices=column.type.enums))
 
         # Add a length validator if a max length is set on the column
-        # Skip UUID columns
-        # (see https://github.com/marshmallow-code/marshmallow-sqlalchemy/issues/54)
+        # Skip UUID and Enum columns
+        # - https://github.com/marshmallow-code/marshmallow-sqlalchemy/issues/54
+        # - https://github.com/marshmallow-code/marshmallow-sqlalchemy/issues/673
         if hasattr(column.type, "length") and not kwargs.get("dump_only"):
             column_length = column.type.length
             if column_length is not None:
                 try:
                     python_type = column.type.python_type
                 except (AttributeError, NotImplementedError):
                     python_type = None
-                if not python_type or not issubclass(python_type, uuid.UUID):
+                if not python_type or not issubclass(
+                    python_type, uuid.UUID | enum.Enum
+                ):
                     kwargs["validate"].append(validate.Length(max=column_length))
 
         if getattr(column.type, "asdecimal", False):

tests/test_conversion.py

@@ -82,6 +82,7 @@ def test_enum_with_class_converted_to_enum_field(self, models):
         field = fields_["level_with_enum_class"]
         assert type(field) is fields.Enum
         assert contains_validator(field, validate.OneOf) is False
+        assert contains_validator(field, validate.Length) is False
         assert field.enum is CourseLevel
 
     def test_many_to_many_relationship(self, models):