What is supposed to happen when an external program changes the device configuration?

[ArcaneNibble]

Suppose another program on the user's computer issues a SET_CONFIGURATION to a USB device. There is currently no mechanism in WebUSB to make this known to a web page, and in practice Chrome currently doesn't seem to notice this and will keep telling the web page an outdated current configuration.

This is especially notable on macOS, because macOS seems to allow programs to change the configuration even when some interfaces are claimed.

[reillyeon]

To avoid a breaking API change the best workaround I can think of is for methods which depend on the current configuration to query it from the operating system before taking actions based on the previously cached value and raise an error if the mismatch prevents the operation from succeeding. To my knowledge no platform provides an event when there is a configuration change.