Fix SARIF parser crash on empty extensions

Handle empty or missing tool.extensions in SARIF parser.

Author: kleomartiny

dojo/tools/sarif/parser.py

@@ -384,11 +384,12 @@ def customize_finding(self, finding, result, rule, location):
 
 def get_rules(run):
     rules = {}
-    rules_array = run["tool"]["driver"].get("rules", [])
-    if len(rules_array) == 0 and run["tool"].get("extensions") is not None:
-        rules_array = run["tool"]["extensions"][0].get("rules", [])
+    rules_array = run['tool']['driver'].get('rules', [])
+    if not rules_array:
+        for extension in run['tool'].get('extensions', []):
+            rules_array.extend(extension.get('rules', []))
     for item in rules_array:
-        rules[item["id"]] = item
+        rules[item['id']] = item
     return rules