kernelci: api: helper: don't crash when adding artifacts to node

Nodes are created with `'artifacts': null`, meaning calling `update()`
could lead to an uncaught exception, and therefore a crash. Avoid this
situation by ensuring this field is a dict before calling `update()`.

Signed-off-by: Arnaud Ferraris <[email protected]>

Author: a-wai

kernelci/api/helper.py

@@ -559,6 +559,8 @@ def submit_results(self, results, root):
         root_node = root.copy()
         root_node['result'] = results['node']['result']
         root_node['state'] = results['node'].get('state', 'done')
+        if root_node.get('artifacts') is None:
+            root_node['artifacts'] = {}
         root_node['artifacts'].update(results['node']['artifacts'])
         root_node['data'].update(results['node'].get('data', {}))
         root_node['processed_by_kcidb_bridge'] = False