Simulator sounds can run when MakeCode is not visible including in quite unexpected cases

[microbit-matt-hillsdon]

Simulator sounds aren't stopped when MakeCode isn't visible. That's potentially a problem in itself but at least when the user does this they can understand what's happened.

Giles reported this more interesting scenario:

Hex file: microbit-giles-weds.hex.zip

Screenshot:

A tone started playing when on the Data Samples page.

Theory: removing all the data for “tap running” leads to it no longer being a valid action in the model and it’s removed from the MakeCode project so MakeCode will change its previous event block to “unknown”. Clicking “Save” (or perhaps some other user or MakeCode triggered actions) causes us to tell MakeCode about that new project, which causes it to restart the simulator behind the scenes. “unknown” which is the sim drop-down default now makes a noise.

Rob suggests you might only need to remove one data sample -- just enough to invalidate the model.

In a scenario where I'd recorded some new data samples for "tap running" to get back to MakeCode I also saw a modal explaining my project had errors (once dismissed the project was fine).

[microbit-robert]

Using devtools we can show what's going on inside MakeCode while the user is making changes in CreateAI.

The model has been trained. MakeCode has been opened an a custom program created. The user has navigated back to the data samples page. All is well.

The user makes any change that invalidates the model. The autogenerated.ts file is cleared by us as there is no valid model. At this point, the change has not been flushed through to MakeCode and it is unaware of any problems.

The user saves a hex file from CreateAI. This forces the flush of the project in its current state through to MakeCode. The various fixedInstance classes (TapOff, TapRunning) are no longer available in MakeCode, so MakeCode shows an error dialog and the fixedInstance values change to the only remaining option, Unknown. This triggers the simulator to restart. The event closest to the top left remains enabled, so the code in this handler runs on the simulator. Other duplicate on Unknown events are disabled.

We can potentially not remove the fixedInstance values from the autogenerated.ts file in some cases, but this means the user can open this hex in MakeCode and it will look like everything will run on the micro:bit device, but it won't. We would need to highlight to the user that the program won't work as expected as there is no model.

[microbit-grace]

One approach #854, though it has an issue. Discussion needed. Suggestions welcomed