Azure · jayesh-tanna · Dec 26, 2025
@@ -14,7 +14,7 @@
 class IndexAssetSchema(ArtifactSchema):
     name = fields.Str(required=True, allow_none=False)
     id = ArmStr(azureml_type=AzureMLResourceType.INDEX, dump_only=True)
-    stage = fields.Str(default="Development")
+    stage = fields.Str(dump_default="Development")
     path = fields.Str(
         required=True,
         metadata={

@@ -11,13 +11,14 @@
 import traceback
 import typing
 from abc import abstractmethod
+from datetime import datetime
 from pathlib import Path
 from typing import List, Optional, Union
 
 from marshmallow import RAISE, fields
 from marshmallow.exceptions import ValidationError
 from marshmallow.fields import Field, Nested
-from marshmallow.utils import FieldInstanceResolutionError, from_iso_datetime, resolve_field_instance
+from marshmallow.fields import _resolve_field_instance as resolve_field_instance  # Private API in marshmallow 4.0
 
 from ..._utils._arm_id_utils import AMLVersionedArmId, is_ARM_id_for_resource, parse_name_label, parse_name_version
 from ..._utils._experimental import _is_warning_cached
@@ -249,7 +250,9 @@ def _serialize(self, value, attr, obj, **kwargs):
 
     def _validate(self, value):
         try:
-            from_iso_datetime(value)
+            # Handle 'Z' UTC indicator which fromisoformat doesn't support
+            normalized_value = value.replace('Z', '+00:00') if isinstance(value, str) else value
+            datetime.fromisoformat(normalized_value)
         except Exception as e:
             raise ValidationError(f"Not a valid ISO8601-formatted datetime string: {value}") from e
 
@@ -418,9 +421,19 @@ class NestedField(Nested):
     """anticipates the default coming in next marshmallow version, unknown=True."""
 
     def __init__(self, *args, **kwargs):
-        if kwargs.get("unknown") is None:
-            kwargs["unknown"] = RAISE
+        # In marshmallow 4.0, 'unknown' is only valid on Schema classes, not Field classes
+        # Extract it from kwargs and apply to schema instance later
+        self._unknown_value = kwargs.pop("unknown", RAISE)
         super().__init__(*args, **kwargs)
+
+    @property
+    def schema(self):
+        """Override to apply unknown setting to the nested schema instance."""
+        nested_schema = super().schema
+        # Apply the unknown setting to the schema instance
+        if nested_schema is not None and hasattr(nested_schema, 'unknown'):
+            nested_schema.unknown = self._unknown_value
+        return nested_schema
 
 
 # Note: Currently contains a bug where the order in which fields are inputted can potentially cause a bug
@@ -432,14 +445,17 @@ class UnionField(fields.Field):
     """A field that can be one of multiple types."""
 
     def __init__(self, union_fields: List[fields.Field], is_strict=False, **kwargs):
+        # In marshmallow 4.0, 'unknown' is only valid on Schema classes, not Field classes
+        # Remove it from kwargs if present
+        kwargs.pop("unknown", None)
         super().__init__(**kwargs)
         try:
             # add the validation and make sure union_fields must be subclasses or instances of
             # marshmallow.base.FieldABC
             self._union_fields = [resolve_field_instance(cls_or_instance) for cls_or_instance in union_fields]
             # TODO: make serialization/de-serialization work in the same way as json schema when is_strict is True
             self.is_strict = is_strict  # S\When True, combine fields with oneOf instead of anyOf at schema generation
-        except FieldInstanceResolutionError as error:
+        except Exception as error:
             raise ValueError(
                 'Elements of "union_fields" must be subclasses or instances of marshmallow.base.FieldABC.'
             ) from error
@@ -552,6 +568,9 @@ def __init__(
                 resolve_field_instance(cls_or_instance) for cls_or_instance in type_sensitive_fields
             ]
 
+        # In marshmallow 4.0, 'unknown' is only valid on Schema classes, not Field classes
+        # Remove it from kwargs before passing to parent UnionField
+        kwargs.pop("unknown", None)
         super(TypeSensitiveUnionField, self).__init__(union_fields, **kwargs)
         self._type_field_name = type_field_name
 
@@ -876,7 +895,7 @@ def __init__(self, experimental_field: fields.Field, **kwargs):
         try:
             self._experimental_field = resolve_field_instance(experimental_field)
             self.required = experimental_field.required
-        except FieldInstanceResolutionError as error:
+        except Exception as error:
             raise ValueError(
                 '"experimental_field" must be subclasses or instances of marshmallow.base.FieldABC.'
             ) from error

@@ -4,12 +4,12 @@
 
 # pylint: disable=unused-argument
 
-from marshmallow import fields, post_load
+from marshmallow import fields, post_load, validate
 from azure.ai.ml._schema.core.schema import PatchedSchemaMeta
 
 
 class ComputeConfigurationSchema(metaclass=PatchedSchemaMeta):
-    compute_type = fields.Str(allowed_values=["ServerlessSpark"])
+    compute_type = fields.Str(validate=validate.OneOf(["ServerlessSpark"]))
 
 
 class ServerlessSparkComputeSchema(ComputeConfigurationSchema):

@@ -70,7 +70,7 @@
         "pyyaml>=5.1.0,<7.0.0",
         "azure-core>=1.23.0",
         "azure-mgmt-core>=1.3.0",
-        "marshmallow>=3.5,<4.0.0",
+        "marshmallow>=3.5,<5.0.0",
         "jsonschema>=4.0.0,<5.0.0",
         "tqdm<5.0.0",
         # Used for PR 825138