@kittaakos is this field used by the IDE?

No, it's unused in IDE2. What's the purpose of this property?

If the board is marked as "hidden" in the platform

It comes from here https://arduino.github.io/arduino-cli/0.33/platform-specification/#hiding-boards
And here works correctly: In the Tools > Board menu the hidden board is not visibile.

The problem is that this field do not have anything to do in filtering of the board list command.

here works correctly: In the Tools > Board menu

Do you mean this in IDE2?

Screenshot 2023年06月23日 at 14 11 23

IDE2 uses the gRPC equivalent of ./arduino-cli board listall to populate the above menu per platform.

Slightly off:

The problem is that this field do not have anything to do in filtering of the board list command.

As a long-time user of the CLI API, I recommend not reusing the same type for different command responses. The commands board search, board listall, and board list are perfect examples. On the gRPC level, all response objects refer to a "board" concept as a BoardListItem, but the props are populated on different conditions. Please make it easier for clients to see what response object structure to expect.

For example, fqbn could be available on a board from the board list command response even if the platform is not installed. This behaves differently for board serarch.

Do you mean this in IDE2?

No, the equivalent of board list is the "Tools > Port" selection menu (DetectedBoard in gRPC world).
What we want to know is: when a hidden board is detected is it displayed in the "Tools > Port" menu?

Previously the matching_boards[].is_hidden field was not populated (even if present in the gRPC structure), it was always false, instead after this patch is now populated correctly:

 {
 "matching_boards": [
 {
 "name": "Arduino Uno R4 WiFi",
 "fqbn": "arduino:renesas_portenta:unor4wifi",
 "is_hidden": true <---------------------
 },
 {
 "name": "Arduino Uno R4 WiFi",
 "fqbn": "arduino:renesas_uno:unor4wifi"
 }
 ],
 "port": {
 "address": "/dev/ttyACM0",
 "label": "/dev/ttyACM0",
 "protocol": "serial",
 "protocol_label": "Serial Port (USB)",
 "properties": {
 "pid": "0x1002",
 "serialNumber": "DC5475C30184",
 "vid": "0x2341"
 },
 "hardware_id": "DC5475C30184"
 }
 },

As a long-time user of the CLI API, I recommend not reusing the same type for different command responses. The commands board search, board listall, and board list are perfect examples. On the gRPC level, all response objects refer to a "board" concept as a BoardListItem, but the props are populated on different conditions. Please make it easier for clients to see what response object structure to expect.

This change is exactly to solve this problem, we reused BoardListItem but the is_hidden field was correctly populated only in the board listall command (so I expect the "hidden" boards to be correctly hidden in the Tools > Board menu).

What we want to know is: when a hidden board is detected is it displayed in the "Tools > Port" menu?

Probably. IDE2 does not use the isHidden property at all.