Error handling if visible_index not found in query report (#3399)

frappe/desk/query_report.py

@@ -129,6 +129,8 @@ def export_query():
 		file_format_type = data["file_format_type"]
 	if isinstance(data.get("visible_idx"), basestring):
 		visible_idx = json.loads(data.get("visible_idx"))
+	else:
+		visible_idx = None
 
 	if file_format_type == "Excel":
 
@@ -154,7 +156,8 @@ def export_query():
 			result = result + data.result
 		
 		# filter rows by slickgrid's inline filter
-		result = [x for idx, x in enumerate(result) if idx == 0 or idx in visible_idx]
+		if visible_idx:
+			result = [x for idx, x in enumerate(result) if idx == 0 or idx in visible_idx]
 
 		from frappe.utils.xlsxutils import make_xlsx
 		xlsx_file = make_xlsx(result, "Query Report")