Keep the connection.id up to date with socket.io client id

The meta.source of an update is populated on the server side so
we need to keep our local connection id up to date with it. When a duplicate
op is submitted we must send all possible client ids that it could have
been sent with.

services/web/public/coffee/ide/editor/Document.coffee

@@ -150,6 +150,12 @@ define [
 				wantToBeJoined: @wantToBeJoined
 				update: update
 
+			if window.disconnectOnAck? and Math.random() < window.disconnectOnAck
+				console.log "Disconnecting on ack", update
+				window._ide.socket.socket.disconnect()
+				# Pretend we never received the ack
+				return
+
 			if window.dropAcks? and Math.random() < window.dropAcks
 				if !update.op? # Only drop our own acks, not collaborator updates
 					console.log "Simulating a lost ack", update

services/web/public/coffee/ide/editor/ShareJsDoc.coffee

@@ -28,13 +28,14 @@ define [
 			@connection = {
 				send: (update) =>
 					@_startInflightOpTimeout(update)
+					if window.disconnectOnUpdate? and Math.random() < window.disconnectOnUpdate
+						console.log "Disconnecting on update", update
+						window._ide.socket.socket.disconnect()
 					if window.dropUpdates? and Math.random() < window.dropAcks
 						console.log "Simulating a lost update", update
 						return
 					@socket.emit "applyOtUpdate", @doc_id, update
 				state: "ok"
-				# Unlike ShareJs, our connection.id never changes, even when we disconnect/reconnect.
-				# This gives this client a unique id used for detecting duplicates ops.
 				id:    @socket.socket.sessionid
 			}
 
@@ -95,6 +96,7 @@ define [
 
 		updateConnectionState: (state) ->
 			@connection.state = state
+			@connection.id = @socket.socket.sessionid
 			@_doc.autoOpen = false
 			@_doc._connectionStateChanged(state)
 
@@ -114,7 +116,13 @@ define [
 				# This can be cleared when hard reloading the document in which
 				# case we don't want to keep trying to send it.
 				if @_doc.inflightOp?
-					update.dupIfSource = [@connection.id]
+					# When there is a socket.io disconnect, @_doc.inflightSubmittedIds
+					# is updated with the socket.io client id of the current op in flight
+					# (meta.source of the op).
+					# @connection.id is the client id of the current socket.io session.
+					# So we need both depending on whether the op was submitted before
+					# one or more disconnects, or if it was submitted during the current session.
+					update.dupIfSource = [@connection.id, @_doc.inflightSubmittedIds...]
 					@connection.send(update)
 				# TODO: Trigger op:timeout only when some max retries have been hit
 				# and we need to do a full reload.