Empty kube config(root/.kube/config) file cause NPE

[tinystorm]

Describe the bug

When I haven't manually disabled AutoConfig and there is an empty kubeconfig file present in the system, it leads to a NullPointerException in the loadFromKubeConfig method.

Fabric8 Kubernetes Client version

other (please specify in additional context)

Steps to reproduce

1 echo '' > root/.kube/config
2 new ConfigBuilder()
3 will get a NPE

Expected behavior

no NPE

Runtime

Kubernetes (vanilla)

Kubernetes API Server version

1.25.3@latest

Environment

Linux

Fabric8 Kubernetes Client Logs

`Caused by: java.lang.NullPointerException
	at io.fabric8.kubernetes.client.Config.loadFromKubeconfig(Config.java:703)
	at io.fabric8.kubernetes.client.Config.tryKubeConfig(Config.java:666)
	at io.fabric8.kubernetes.client.Config.autoConfigure(Config.java:286)
	at io.fabric8.kubernetes.client.Config.<init>(Config.java:251)
	at io.fabric8.kubernetes.client.Config.<init>(Config.java:242)
	at io.fabric8.kubernetes.client.ConfigBuilder.<init>(ConfigBuilder.java:10)
	at io.fabric8.kubernetes.client.ConfigBuilder.<init>(ConfigBuilder.java:7)
	at `

Additional context

version is 6.6.0
Based on the following code, it seems that you are consciously trying to prevent empty kubeconfig files. However, you are currently only checking for null and not checking for an empty string "".
if (kubeconfigContents == null) { return false; }