Calling CLICommandInvoker.invoke() changes Jenkins authorization as a side effect which means that many operations against Jenkins model failed later.

It is a quite common to prepare data in Jenkins instance, call CLI command and verify the state of Jenkins model later.

How-to reproduce:

JenkinsRule j = new JenkinsRule();
j.createFreeStyleProject("aProject");
j.jenkins.getItem("aProject").getDisplayName() // OK -> 'aProject'
CLICommandInvoker command = new CLICommandInvoker(j, "version");
CLICommandInvoker.Result result = command.authorizedTo(Jenkins.READ).invoke();
j.jenkins.getItem("aProject").getDisplayName() // Fail -> NPE

How-to fix:

• in CLICommandInvoker.setAuth() save current SecurityRealm, AuthorizationStrategy and thread's SecurityContext
• in CLICommandInvoker.invoke() after result = new Result(returnCode, out, err); call a new method restoreAuth()
• implement a new method CLICommandInvoker.restoreAuth() where SecurityRealm, AuthorizationStrategy and thread's SecurityContext is set to previously saved values