frobar: More corner cases

hm/desktop/frobar/frobar/common.py

@@ -370,7 +370,11 @@ class Bar(ComposableText):
             while True:
                 line = await proc.stdout.readline()
                 command = line.decode().strip()
-                callback = self.actions[command]
+                callback = self.actions.get(command)
+                if callback is None:
+                    # In some conditions on start it's empty
+                    log.error(f"Unknown command: {command}")
+                    return
                 callback()
 
         async with self.taskGroup: