From bb2e396fc2bf21e340b4a6863e54d1f6f0b560a4 Mon Sep 17 00:00:00 2001
From: devteamaegis <devteam.aegis@gmail.com>
Date: Sun, 31 May 2026 23:28:58 -0400
Subject: [PATCH] fix(jsonschema): guard against empty types list in
 schema_to_type and create_array_type

When the JSON Schema "type" field is a list containing only "null",
schema_to_type() filtered out type(None) and crashed with IndexError
on the now-empty list. Similarly, create_array_type() crashed with
TypeError when "items" was an empty list, because Union[tuple([])]
is invalid in Python.

Fixes #1353
---
 src/marvin/utilities/jsonschema.py       |  4 +++-
 tests/basic/utilities/test_jsonschema.py | 11 +++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/marvin/utilities/jsonschema.py b/src/marvin/utilities/jsonschema.py
index 2f6c356f8..50ec3d66b 100644
--- a/src/marvin/utilities/jsonschema.py
+++ b/src/marvin/utilities/jsonschema.py
@@ -217,7 +217,7 @@ def create_array_type(
         item_types = [schema_to_type(s, schemas) for s in items]
         from typing import Union
 
-        combined = Union[tuple(item_types)]
+        combined = Union[tuple(item_types)] if item_types else Any
         base = list[combined]
     else:
         # Handle single item schema
@@ -296,6 +296,8 @@ def schema_to_type(
             types.append(schema_to_type(type_schema, schemas))
         has_null = type(None) in types
         types = [t for t in types if t is not type(None)]
+        if not types:
+            return type(None)
         if has_null:
             from typing import Union
 
diff --git a/tests/basic/utilities/test_jsonschema.py b/tests/basic/utilities/test_jsonschema.py
index b55b2dd89..805e1a1e2 100644
--- a/tests/basic/utilities/test_jsonschema.py
+++ b/tests/basic/utilities/test_jsonschema.py
@@ -1063,6 +1063,17 @@ def test_mixed_type_array(self):
         result = validator.validate_python(["test", 123, True])
         assert result == ["test", 123, True]
 
+    def test_null_only_type_list_returns_none_type(self):
+        # {"type": ["null"]} previously raised IndexError after filtering out NoneType
+        result = jsonschema_to_type({"type": ["null"]})
+        assert result is type(None)
+
+    def test_array_with_empty_items_list_does_not_crash(self):
+        # {"type": "array", "items": []} previously raised TypeError in Union
+        result = jsonschema_to_type({"type": "array", "items": []})
+        validator = TypeAdapter(result)
+        assert validator.validate_python([]) == []
+
 
 class TestNameHandling:
     """Test suite for schema name handling."""