Be careful with Yaml editing

The other day I have almost erased an application of mine in App Engine the only thing that saved my day is that I was working on a version.

So how this happened to me ?

Well you edit your yaml file which probably have been copy/pasted from some other application , you read it, you are satisfied with what you see and you decide to upload on the spot so here we are: appcfg ... and presto your old application is gone coz you forgot to save this yaml which looked good to your eyes.

You see appcfg does not read through your own eyes it prefers its own devices which can read a complete different story than yours.