Allow identification of a specific instance of a board from a Pluggable Discovery

[cmaglie]

Describe the request

We can use the USB serial number to know that a board has changed COM port, for example after an upload, or when it swaps to bootloader mode after a double-tap on the reset button.

Currently the discovery returns this information:

{
  "eventType": "list",
  "ports": [
    {
      "address": "/dev/ttyACM0",
      "label": "/dev/ttyACM0",
      "properties": {
        "pid": "0x804e",
        "vid": "0x2341",
        "serialNumber": "EBEABFD6514D32364E202020FF10181E"
      },
      "protocol": "serial",
      "protocolLabel": "Serial Port (USB)"
    }
  ]
}

we may extend the result by adding an extra field hardwareId that is populated when we have an hardware identification number available, for example for USB serial ports we can use the USB Serial Number:

{
  "eventType": "list",
  "ports": [
    {
      "address": "/dev/ttyACM0",
      "label": "/dev/ttyACM0",
      "hardwareId": "EBEABFD6514D32364E202020FF10181E",
      "properties": {
        "pid": "0x804e",
        "vid": "0x2341",
        "serialNumber": "EBEABFD6514D32364E202020FF10181E"
      },
      "protocol": "serial",
      "protocolLabel": "Serial Port (USB)"
    }
  ]
}

This change may require an update to the Pluggable Discovery specification.

Describe the current behavior

When a board changes the port after a reset, there is no reliable way to determine if the new port belongs to the same board.
With this proposal implemented the IDE may exploit the hardwareId field to reselect the correct port automatically.

Arduino CLI version

6bf2c23

Operating system

N/A

Operating system version

N/A

Additional context

cc @pnndra @kittaakos @per1234 @umbynos

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the nightly build
• My report contains all necessary details

[umbynos]

@facchinm can we assume the serialNumber is unique?

[facchinm]

Most of the times yes; if using a PluggableUSB module (like Keyboard, Mouse or MIDIUSB) the serial number reported will change a bit (but I think it's a corner case compared with the vast majority of the use cases)

[cmaglie]

Thinking on this a bit more, this is not related specifically to serial but its a broader change to the Pluggable Discovery specification, I'm moving the issue to the arduino-cli repo.

[umbynos]

@cmaglie is the serial number exposed even in case of the network discovery?

no, but we can use the mac address