fix: emit error on timeout request and disconnect

[olzzon]

About the Contributor

This PR is made on behalf of TV2 NO

Type of Contribution

This is a:
Bug fix

Current Behavior

Currently disconnection and timeout of request could cause an unhandled crash, that couldn't be caught by a try-catch in the main program.

New Behavior

disconnection and request issues (timeout & wrong request) now emit's an error for the main program to handle.

Testing Instructions

Connect an Ember client to a host and close the socket, this will crash the main program.

Status

• PR is ready to be reviewed.
• The functionality has been tested by the author.
• Relevant unit tests has been added / updated.
• Relevant documentation (code comments, system documentation) has been added / updated.

[jstarpl]

I think these changes will make pending requestPromise.response promises never resolved or rejected, which would be a potential memory leak. I think the root of the problem might be that most user-code will await the individual _sendCommand-wrapping methods exposing the business functionality, and not really await the requestResponse.promise that would be rejected here.

Maybe one option would be to add a requestResponse.promise.catch(noOp) into _sendRequest to avoid an unhandled rejection exception, while still allowing client code to do it's own catch, if it wants to - but avoiding having floating promises?

[olzzon]

I think these changes will make pending requestPromise.response promises never resolved or rejected, which would be a potential memory leak. I think the root of the problem might be that most user-code will await the individual _sendCommand-wrapping methods exposing the business functionality, and not really await the requestResponse.promise that would be rejected here.

but awaiting the requestResponse.promise has never solved the problem. (although it should)

[olzzon]

This PR will be closed, solved by guards around things in Sisyfos.
Issues in the way sofie-emberplus-connection is throwing errors still exists.
If a disconnection error occurs, the EmberClient library itself, specifically in the S101Client disconnection handling is throwing an error before it reaches the host programs event handlers.

But as this can be handled in the main program, this PR will be closed.