fix: only do this when extensions is defined

Author: ma-ts

kubernetes/base/config/exec_provider.py

@@ -81,10 +81,11 @@ def run(self, previous_response=None):
             kubernetes_exec_info['spec']['response'] = previous_response
         if self.cluster:
             kubernetes_exec_info['spec']['cluster'] = self.cluster.value
-            for extension in self.cluster.value["extensions"]:
-                if extension["name"] == "client.authentication.k8s.io/exec":
-                    kubernetes_exec_info["spec"]["cluster"]["config"] = extension["extension"]
-                    break            
+            if self.cluster.value.get("extensions"):
+                for extension in self.cluster.value["extensions"]:
+                    if extension["name"] == "client.authentication.k8s.io/exec":
+                        kubernetes_exec_info["spec"]["cluster"]["config"] = extension["extension"]
+                        break
 
         self.env['KUBERNETES_EXEC_INFO'] = json.dumps(kubernetes_exec_info)
         process = subprocess.Popen(