Merge pull request #57750 from frappe/mergify/bp/version-16-hotfix/pr-57747

fix: disabled item attribute blocks unrelated edits to existing variants (backport #57747)

erpnext/stock/doctype/item/item.py

@@ -853,7 +853,17 @@ class Item(Document):
 				frappe.throw(_("Item {0} is not a template item.").format(frappe.bold(self.variant_of)))
 
 			if based_on == "Item Attribute":
+				previous_doc = self.get_doc_before_save()
+				saved_attributes = (
+					{(row.attribute, row.attribute_value) for row in previous_doc.attributes}
+					if previous_doc
+					else set()
+				)
+
 				for d in self.attributes:
+					if (d.attribute, d.attribute_value) in saved_attributes:
+						continue
+
 					if not frappe.db.exists(
 						"Item Variant Attribute", {"attribute": d.attribute, "parent": self.variant_of}
 					):

erpnext/stock/doctype/item/test_item.py

@@ -410,6 +410,24 @@ class TestItem(ERPNextTestSuite):
 
 		self.assertRaises(InvalidItemAttributeValueError, attribute.save)
 
+	def test_disabled_attribute_blocks_only_attribute_changes(self):
+		frappe.delete_doc_if_exists("Item", "_Test Variant Item-L", force=1)
+
+		variant = create_variant("_Test Variant Item", {"Test Size": "Large"})
+		variant.save()
+
+		attribute = frappe.get_doc("Item Attribute", "Test Size")
+		attribute.disabled = 1
+		attribute.save()
+
+		variant.reload()
+		variant.description = "Edited after the attribute was disabled"
+		variant.save()
+
+		variant.reload()
+		variant.attributes[0].attribute_value = "Small"
+		self.assertRaises(frappe.ValidationError, variant.save)
+
 	def test_rename_attribute_value_updates_variants(self):
 		frappe.delete_doc_if_exists("Item", "_Test Variant Item-L", force=1)