add check_for_errors_in_dkt_values function

src/nme/__init__.py

@@ -7,7 +7,7 @@
     rename_key,
     update_argument,
 )
-from ._serialize_hooks import NMEEncoder, nme_object_encoder, nme_object_hook
+from ._serialize_hooks import NMEEncoder, check_for_errors_in_dkt_values, nme_object_encoder, nme_object_hook
 from .version import version as __version__
 
 
@@ -47,6 +47,7 @@ def nme_cbor_decoder(decoder, value):
 
 __all__ = (
     "class_to_str",
+    "check_for_errors_in_dkt_values",
     "register_class",
     "nme_object_hook",
     "rename_key",

src/nme/_serialize_hooks.py

@@ -116,6 +116,16 @@ def default(self, o):
         return val
 
 
+def check_for_errors_in_dkt_values(dkt: dict) -> typing.List[str]:
+    """
+    Function checking if any of values in dict contains ``"__error__"`` key.
+
+    :param dkt: dictionary to check.
+    :return: list of keys that value is dict containing ``"__error__"`` key.
+    """
+    return [key for key, value in dkt.items() if isinstance(value, dict) and "__error__" in value]
+
+
 def nme_object_hook(dkt: dict) -> typing.Any:
     """
     Function restoring supported types from :py:func:`nme_object_encoder` function output.
@@ -133,6 +143,10 @@ def nme_object_hook(dkt: dict) -> typing.Any:
             cls_str = dkt.pop("__class__")
             version_dkt = dkt.pop("__class_version_dkt__") if "__class_version_dkt__" in dkt else {cls_str: "0.0.0"}
             dkt = {"__values__": dkt, "__class__": cls_str, "__class_version_dkt__": version_dkt}
+        problematic_fields = check_for_errors_in_dkt_values(dkt["__values__"])
+        if problematic_fields:
+            dkt["__error__"] = f"Error in fields: {', '.join(problematic_fields)}"
+            return dkt
         try:
             dkt_migrated = REGISTER.migrate_data(dkt["__class__"], dkt["__class_version_dkt__"], dkt["__values__"])
             cls = REGISTER.get_class(dkt["__class__"])

src/tests/test_json_hooks.py

@@ -8,7 +8,7 @@
 import pytest
 from napari.utils import Colormap
 from napari.utils.notifications import NotificationSeverity
-from pydantic import BaseModel, dataclasses
+from pydantic import BaseModel, Extra, dataclasses
 
 from nme import NMEEncoder, nme_object_hook, register_class, rename_key
 from nme._class_register import class_to_str
@@ -230,6 +230,32 @@ class MainClass(BaseClass):
         ob = json.loads(data_str, object_hook=nme_object_hook)
         assert isinstance(ob, MainClass)
 
+    def test_error_in_object_restore(self, clean_register):
+        @register_class
+        class SubClass(BaseModel, extra=Extra.forbid):
+            field: int = 1
+
+        @register_class
+        class MainClass(BaseModel):
+            field: int = 1
+            sub11: SubClass = SubClass()
+
+        data_str = """
+        {"__class__": "test_json_hooks.TestNMEObjectHook.test_error_in_object_restore.<locals>.MainClass",
+        "__class_version_dkt__":
+        {"test_json_hooks.TestNMEObjectHook.test_error_in_object_restore.<locals>.MainClass": "0.0.0"},
+        "__values__": {"field": 1,
+        "sub11": {"__class__": "test_json_hooks.TestNMEObjectHook.test_error_in_object_restore.<locals>.SubClass",
+        "__class_version_dkt__":
+        {"test_json_hooks.TestNMEObjectHook.test_error_in_object_restore.<locals>.SubClass": "0.0.0"},
+        "__values__": {"field": 1, "eee": 1}}}}
+        """
+
+        ob = json.loads(data_str, object_hook=nme_object_hook)
+        assert isinstance(ob, dict)
+        assert "__error__" in ob
+        assert ob["__error__"] == "Error in fields: sub11"
+
 
 class DummyClassForTest:
     class DummySubClassForTest: