We want to update message.submessages for new events, even
though our couple of widgets (poll/tictactoe) that can process
"update" events currently just apply events as "deltas"
to their current data.
This does fix a subtle issue where you may get incoming
events for a message that the client knows about but which
it hasn't yet activated as a widget. Up until now,
we've rarely seen the bug that's fixed here, since it's
usually the case that as soon as we receive a message, we
widgetize it right away.
For some reason in my original version I was sending both
content and data to the client for submessage events,
where data === JSON.parse(content). There's no reason
to not just let the client parse it, since the client
already does it for data that comes on the original
message, and since we might eventually have non-JSON
payloads.
The server still continues to validate that the payload
is JSON, and the client will blueslip if the server
regressses and sends bad JSON for some reason.
We should probably have a try/catch in MessageListView itself
too, for post-processing kind of stuff, but we want to make
this new module defensive in its own right.
Having submessages will become common enough that the
info message here is too spammy, and there are other
ways to observe incoming submessages if you're doing dev
debugging, which this was originally written for.
This commit lays the foundation to handle submessages for
plugin widgets. Right now it just logs events, but subsequent
commits will add widget functionality.
Steve Howell