From 7a9b25f6f6805347c719b8648f2efd1320692c0d Mon Sep 17 00:00:00 2001
From: Matt Stone <matt@fulcrumgenomics.com>
Date: Wed, 4 Mar 2026 08:48:18 -0800
Subject: [PATCH] fix: Shallow copy input dict in `_empty_field_to_none`
 validator

Avoid mutating the caller's dict by making a shallow copy before
modifying empty Optional fields.

Co-Authored-By: Rahul Kaushal <kaushalrahul15@gmail.com>
---
 fgmetric/metric.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fgmetric/metric.py b/fgmetric/metric.py
index f06c809..35f5543 100644
--- a/fgmetric/metric.py
+++ b/fgmetric/metric.py
@@ -82,6 +82,8 @@ def _empty_field_to_none(cls, data: Any) -> Any:
             # short circuit
             return data
 
+        data = dict(data)
+
         for field, value in data.items():
             info = cls.model_fields.get(field)
             if info is None: