From 7e11c817a70ee7c650559c731dab56caa13858bf Mon Sep 17 00:00:00 2001
From: Vitor Hideyoshi <vitor.h.n.batista@gmail.com>
Date: Tue, 19 Aug 2025 22:25:36 -0300
Subject: [PATCH] (fix): Adds check for discriminator type

---
 jambo/parser/oneof_type_parser.py      | 16 +++++++++++++---
 tests/parser/test_oneof_type_parser.py | 23 +++++++++++++++++++++++
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/jambo/parser/oneof_type_parser.py b/jambo/parser/oneof_type_parser.py
index 12b62fe..b9393fe 100644
--- a/jambo/parser/oneof_type_parser.py
+++ b/jambo/parser/oneof_type_parser.py
@@ -1,8 +1,8 @@
 from jambo.parser._type_parser import GenericTypeParser
 from jambo.types.type_parser_options import TypeParserOptions
 
-from pydantic import BeforeValidator, Field, TypeAdapter, ValidationError
-from typing_extensions import Annotated, Any, Union, Unpack
+from pydantic import BaseModel, BeforeValidator, Field, TypeAdapter, ValidationError
+from typing_extensions import Annotated, Any, Union, Unpack, get_args
 
 
 class OneOfTypeParser(GenericTypeParser):
@@ -16,7 +16,7 @@ class OneOfTypeParser(GenericTypeParser):
         if "oneOf" not in properties:
             raise ValueError(f"Invalid JSON Schema: {properties}")
 
-        if not isinstance(properties["oneOf"], list):
+        if not isinstance(properties["oneOf"], list) or len(properties["oneOf"]) == 0:
             raise ValueError(f"Invalid JSON Schema: {properties['oneOf']}")
 
         mapped_properties = self.mappings_properties_builder(properties, **kwargs)
@@ -57,6 +57,16 @@ class OneOfTypeParser(GenericTypeParser):
         if not isinstance(discriminator_prop, dict):
             raise ValueError("Discriminator must be a dictionary")
 
+        for field in subfield_types:
+            field_type, field_info = get_args(field)
+
+            if issubclass(field_type, BaseModel):
+                continue
+
+            raise ValueError(
+                "When using a discriminator, all subfield types must be of type 'object'."
+            )
+
         property_name = discriminator_prop.get("propertyName")
         if property_name is None or not isinstance(property_name, str):
             raise ValueError("Discriminator must have a 'propertyName' key")
diff --git a/tests/parser/test_oneof_type_parser.py b/tests/parser/test_oneof_type_parser.py
index b559a0a..69104ae 100644
--- a/tests/parser/test_oneof_type_parser.py
+++ b/tests/parser/test_oneof_type_parser.py
@@ -196,6 +196,29 @@ class TestOneOfTypeParser(TestCase):
         with self.assertRaises(ValueError):
             Model(pet={"type": "bird", "flies": True})
 
+    def test_oneof_with_invalid_types(self):
+        with self.assertRaises(ValueError):
+            SchemaConverter.build(
+                {
+                    "title": "Pet",
+                    "type": "object",
+                    "properties": {
+                        "pet": {
+                            "oneOf": [
+                                {
+                                    "type": "number",
+                                },
+                                {
+                                    "type": "string",
+                                },
+                            ],
+                            "discriminator": {"propertyName": "type"},
+                        }
+                    },
+                    "required": ["pet"],
+                }
+            )
+
     def test_oneof_with_discriminator_mapping(self):
         schema = {
             "title": "Vehicle",