[Bug] Unresponsive stop button after idle for a few minutes

[laurensvalk]

Describe the bug

I was working on this demo. Usually, the hub and/or Pybricks Code got stuck, unable to stop, if I left it on for a few minutes while working on the article.

I think Pybricks Code recovered after manually shutting down the hub with a long button press, so no hard refresh was required.

To reproduce
Run this demo. Press a few keys drive around. Then forget about the robot while you leave it running.

Drink a coffee and come back. Find Pybricks Code and the hub unresponsive.

Pybricks Code v1.0.0-beta.14

Version 89.0.4389.90 (Official Build) Built on Ubuntu , running on Ubuntu 18.04 (64-bit)

Expected behavior
Keep working after ☕

On the Pybricks Code side, I expected something to happen when I clicked stop, such as an error or disconnect.

Screenshots

[dlech]

I have a feeling that this is the same sort of firmware problem as #304 and/or #232.

From the Pybricks Code side, there is currently nothing in the Pybricks protocol that acknowledges the receipt of a command. And it is possible for user programs to catch a SystemExit exception, so Pybricks Code shouldn't necessarily expect for a program to actually stop after the stop button is pressed.

[laurensvalk]

I have a feeling that this is the same sort of firmware problem

Same here, but I thought I'd keep reporting in order to get a minimal / reproducable case.

[laurensvalk]

This should be fixed by #306.