fix(DX): Throw error when unsupported input is sent (#37438)

frappe/handler.py

@@ -265,6 +265,10 @@ def run_doc_method(method, docs=None, dt=None, dn=None, arg=None, args=None):
 	if dt:  # not called from a doctype (from a page)
 		if not dn:
 			dn = dt  # single
+
+		if not isinstance(dn, str | int):
+			frappe.throw("'dn' must be a string or an integer")
+
 		doc = frappe.get_doc(dt, dn, check_permission=True)
 
 	else: