Final fix

Pydantic v2 copies the class-level attribute into the core schema as
the field default.  Because ``setattr(new_class, field_name,
ExpressionProxy)``
runs *after* ``super().__new__()``, the core schema already contains the
parent class's ExpressionProxy as the default for ``pk`` (and any other
inherited field).  We must rebuild the schema so that Pydantic reads the
newly-set class attribute instead of the stale inherited one.

Additionally, for ``pk`` specifically, we need to clear the
``ExpressionProxy`` from the ``FieldInfo`` default so that
``model_validate`` and ``model_validate_json`` don't try to validate
it as a string.

Author: XChikuX

aredis_om/model/model.py

@@ -1974,8 +1974,21 @@ def __new__(cls, name, bases, attrs, **kwargs):  # noqa C901
                 setattr(new_class, score_attr, None)
                 new_class.__annotations__[score_attr] = Union[float, None]
 
-        if getattr(new_class._meta, "embedded", False):
-            new_class.model_rebuild(force=True)
+        # Pydantic v2 copies the class-level attribute into the core schema as
+        # the field default.  Because ``setattr(new_class, field_name, ExpressionProxy)``
+        # runs *after* ``super().__new__()``, the core schema already contains the
+        # parent class's ExpressionProxy as the default for ``pk`` (and any other
+        # inherited field).  We must rebuild the schema so that Pydantic reads the
+        # newly-set class attribute instead of the stale inherited one.
+        #
+        # Additionally, for ``pk`` specifically, we need to clear the
+        # ``ExpressionProxy`` from the ``FieldInfo`` default so that
+        # ``model_validate`` and ``model_validate_json`` don't try to validate
+        # it as a string.
+        pk_field = new_class.model_fields.get("pk")
+        if pk_field is not None and getattr(pk_field, "default", None) is not None:
+            pk_field.default = None
+        new_class.model_rebuild(force=True)
 
         # If this is an embedded model, we don't want to allow primary keys at all,
         if getattr(new_class._meta, "embedded", False):

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "pyredis-om"
-version = "0.6.4"
+version = "0.6.5"
 description = "A drop-in replacement for `redis-om`, built out of frustration."
 authors = [
     { name = "Redis OSS", email = "oss@redis.com" },

tests/test_pydantic_compat.py

@@ -80,6 +80,30 @@ class RedisUser(JsonModel):
     assert user_dict["operations"]["likes"][0]["pk"] == "alice:bob"
 
 
+def test_json_model_validate_missing_pk():
+    """model_validate on JsonModel must not crash when pk is omitted."""
+
+    class User(JsonModel):
+        name: str
+
+    user = User.model_validate({"name": "Ada"})
+    assert user.name == "Ada"
+    assert user.pk is not None
+    assert isinstance(user.pk, str)
+
+
+def test_json_model_validate_json_missing_pk():
+    """model_validate_json on JsonModel must not crash when pk is omitted."""
+
+    class User(JsonModel):
+        name: str
+
+    user = User.model_validate_json('{"name": "Ada"}')
+    assert user.name == "Ada"
+    assert user.pk is not None
+    assert isinstance(user.pk, str)
+
+
 def test_field_validator_on_hashmodel():
     class TaggedItem(HashModel):
         name: str