Backup requires a valid storage path

[jrieken]

It seem that there is a conceptual flow with notebook documents. In the extension, when adding a new notebook document (here), we make the assumption that the content provider resides inside the same extension host. This must not be true, e.g there can be a remote extension or the web worker extension host. These kind of assumption can never be made

ERR Error: Backup requires a valid storage path
	at ExtHostNotebookDocument.getNewBackupUri (extHostNotebookDocument.js:143)
	at ExtHostNotebookController.$backup (extHostNotebook.js:401)
	at RPCProtocol._doInvokeHandler (rpcProtocol.js:348)
	at RPCProtocol._invokeHandler (rpcProtocol.js:333)
	at RPCProtocol._receiveRequest (rpcProtocol.js:255)
	at RPCProtocol._receiveOneMessage (rpcProtocol.js:188)
	at rpcProtocol.js:69
	at Emitter.fire (event.js:479)
	at BufferedEmitter.fire (ipc.net.js:375)
	at /Users/jrieken/Code/vscode/out/vs/workbench/services/extensions/node/extensionHostProcessSetup.js:146
	at Emitter.fire (event.js:479)
	at BufferedEmitter.fire (ipc.net.js:375)
	at PersistentProtocol._receiveMessage (ipc.net.js:654)
	at ipc.net.js:510
	at Emitter.fire (event.js:479)
	at ProtocolReader.acceptChunk (ipc.net.js:189)
	at ipc.net.js:158
	at Socket.listener (ipc.net.js:17)
	at Socket.emit (events.js:315)
	at addChunk (_stream_readable.js:295)
	at readableAddChunk (_stream_readable.js:271)
	at Socket.push (_stream_readable.js:212)
	at Pipe.onStreamRead (internal/stream_base_commons.js:186)