fix: Manually link_fields from flags before rename_doc

erpnext/patches/v13_0/healthcare_lab_module_rename_doctypes.py

@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 import frappe
 from frappe.model.utils.rename_field import rename_field
 
+
 def execute():
 	if frappe.db.exists('DocType', 'Lab Test') and frappe.db.exists('DocType', 'Lab Test Template'):
 		# rename child doctypes
@@ -17,7 +18,12 @@ def execute():
 		frappe.reload_doc('healthcare', 'doctype', 'lab_test_template')
 
 		for old_dt, new_dt in doctypes.items():
-			if not frappe.db.table_exists(new_dt) and frappe.db.table_exists(old_dt):
+			frappe.flags.link_fields = {}
+			should_rename = (
+				frappe.db.table_exists(old_dt)
+				and not frappe.db.table_exists(new_dt)
+			)
+			if should_rename:
 				frappe.reload_doc('healthcare', 'doctype', frappe.scrub(old_dt))
 				frappe.rename_doc('DocType', old_dt, new_dt, force=True)
 				frappe.reload_doc('healthcare', 'doctype', frappe.scrub(new_dt))