Disconnect dangling clients

[kim]

When replaying the commitlog, keep track of unpaired connect/disconnect calls and call disconnect when instantiating the module.

Expected complexity level and risk

2

Testing

• Tested with quickstart-chat like so:

  • edit quickstart-chat to log connect / disconnect calls
  • publish quickstart-chat module
  • start client
  • shutdown server
  • start server
  • start client (to force module to be loaded)
  • stop client
  • examine module logs to convince thyself that connect is always paired with disconnect

[gefjon]

Looks good. Minor suggestions for doc comments.

I hate to do this to you after you implemented this functionality, but I think we should seriously consider an st_connected_clients system table rather than this strategy because of the interaction with snapshotting.

[bfops]

Fixes #1178

[kim]

we should seriously consider an st_connected_clients system table

I'm not opposed to this, but it will be a breaking change. If that's ok, or we're willing to delay this change until it is ok, we can go the other route np.

[gefjon]

we should seriously consider an st_connected_clients system table

I'm not opposed to this, but it will be a breaking change. If that's ok, or we're willing to delay this change until it is ok, we can go the other route np.

I think certainly we're fine with breaking changes at this stage. I don't know to what extent we're willing to delay this PR; that's a question for @cloutiertyler .

[cloutiertyler]

If tested, then this LGTM