From 41fa15163174fadc0c3a33762b13e27851047a0c Mon Sep 17 00:00:00 2001
From: BipedalBit <me@bipedalbit.net>
Date: Sat, 7 Jun 2025 01:18:47 +0800
Subject: [PATCH] fix: return to break loop of $ref in schema, avoid some case
 of Custom-field-not-found exception.

---
 src/mcpo/tests/__init__.py  |  0
 src/mcpo/tests/test_main.py | 15 +++++++++++++++
 src/mcpo/utils/main.py      | 13 +++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 src/mcpo/tests/__init__.py

diff --git a/src/mcpo/tests/__init__.py b/src/mcpo/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/mcpo/tests/test_main.py b/src/mcpo/tests/test_main.py
index a7cfe5f..9f46ab6 100644
--- a/src/mcpo/tests/test_main.py
+++ b/src/mcpo/tests/test_main.py
@@ -310,3 +310,18 @@ def test_multi_type_property_with_any_of():
 
     # assert result_field parameter config
     assert result_field.description == "A property with multiple types"
+
+
+def test_ref_to_parent_node():
+    schema = {'$ref': '#/properties/data/properties/children/items'}
+    result_type, result_field = _process_schema_property(
+        _model_cache,
+        schema,
+        "generate_fishbone_diagram_form_model_data_model_children_item_model_children",
+        "item",
+        False,
+        {}
+    )
+
+    assert result_type == Any
+    assert result_field.description == ""
\ No newline at end of file
diff --git a/src/mcpo/utils/main.py b/src/mcpo/utils/main.py
index 49fc257..8799c5c 100644
--- a/src/mcpo/utils/main.py
+++ b/src/mcpo/utils/main.py
@@ -93,6 +93,19 @@ def _process_schema_property(
     """
     if "$ref" in prop_schema:
         ref = prop_schema["$ref"]
+        if ref.startswith("#/properties/"):
+            # Remove common prefix in pathes.
+            prefix_path = model_name_prefix.split("_form_model_")[-1]
+            ref_path = ref.split("#/properties/")[-1]
+            # Translate $ref path to model_name_prefix style.
+            ref_path = ref_path.replace("/properties/", "_model_")
+            ref_path = ref_path.replace("/items", "_item")
+            # If $ref path is a prefix substring of model_name_prefix path,
+            # there exists a circular reference.
+            # The loop should be broke with a return to avoid exception.
+            if prefix_path.startswith(ref_path):
+                # TODO: Find the exact type hint for the $ref.
+                return Any, Field(default=None, description="")
         ref = ref.split("/")[-1]
         assert ref in schema_defs, "Custom field not found"
         prop_schema = schema_defs[ref]