WebSocket CLI not working from hpi:run

[jglick]

In both 2.361.x and 2.401.x, a controller started with hpi:run does not serve WebSocket CLI requests:

java.lang.NullPointerException
	at jenkins.websocket.Jetty10Provider.handle(Jetty10Provider.java:67)
	at jenkins.websocket.WebSockets.lambda$upgrade$0(WebSockets.java:70)

or

java.lang.NullPointerException
	at jenkins.websocket.Jetty10Provider.init(Jetty10Provider.java:68)
	at jenkins.websocket.Jetty10Provider.handle(Jetty10Provider.java:75)
	at jenkins.websocket.WebSockets.lambda$upgrade$0(WebSockets.java:70)

Looks like

JettyWebSocketServerContainer.getContainer(req.getServletContext())

is null. I am guessing this broke in #409 but have not checked yet. websocket-core-server-10.0.15.jar are in the classpath of the plugin but perhaps something else needs to be done to activate WebSocket. Have also not yet checked whether WebSocket agents work, but I suppose not, given that the error is in WebSockets before the specific handler code is even run.

[basil]

I am guessing this broke in #409 but have not checked yet.

This is an allegation of a regression without proof. If there is proof of a regression, I will investigate this ticket.

If there is merely an allegation without proof, I will not investigate.