ESP32-S3 board.json USB-CDC build variables ignored

[nomakewan]

PROBLEM DESCRIPTION

A clear and concise description of what the problem is.

When defining options related to the USB Mode and CDC engine, the build flags appear to be ignored if I set them as build variables and are only heeded if they are set as explicit extra_flags instead.

If we look at the Arduino core from upstream we can see how these flags should work:

https://github.com/espressif/arduino-esp32/blob/f6b1910e8ba5a9aff99fa00b2133b10f34f85e4f/platform.txt#L80

However, this board definition does not work (instead, CDC defaults to 0):

{
  "build": {
    "arduino": {
      "partitions": "partitions/no_spiffs_16mb.csv",
      "memory_type": "qio_opi"
    },
    "core": "esp32",
    "extra_flags": [
      "-DARDUINO_ESP32S3_DEV",
      "-DARDUINO_RUNNING_CORE=1",
      "-DARDUINO_EVENT_RUNNING_CORE=1",
      "-DBOARD_HAS_PSRAM"
    ],
    "f_cpu": "240000000L",
    "f_flash": "80000000L",
    "flash_mode": "qio",
    "psram_type": "opi",
    "usb_mode": "1",
    "cdc_on_boot": "1",
    "msc_on_boot": "0",
    "dfu_on_boot": "0",
    "hwids": [
      ["0x303A", "0x1001"]
    ],
    "mcu": "esp32s3",
    "variant": "esp32s3"
  },
  "frameworks": ["arduino"],
  "name": "ESP32-S3 N16R8",
  "upload": {
    "flash_size": "16MB",
    "maximum_ram_size": 327680,
    "maximum_size": 16777216,
    "protocol": "esptool",
    "require_upload_port": true,
    "speed": 921600
  },
  "url": "https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf",
  "vendor": "Espressif"
}

This board definition which instead removes the build variables and replaces them with explicit extra_flags works:

{
  "build": {
    "arduino": {
      "partitions": "partitions/no_spiffs_16mb.csv",
      "memory_type": "qio_opi"
    },
    "core": "esp32",
    "extra_flags": [
      "-DARDUINO_ESP32S3_DEV",
      "-DARDUINO_RUNNING_CORE=1",
      "-DARDUINO_EVENT_RUNNING_CORE=1",
      "-DARDUINO_USB_MODE=1",
      "-DARDUINO_USB_CDC_ON_BOOT=1",
      "-DARDUINO_USB_MSC_ON_BOOT=0",
      "-DARDUINO_USB_DFU_ON_BOOT=0",
      "-DBOARD_HAS_PSRAM"
    ],
    "f_cpu": "240000000L",
    "f_flash": "80000000L",
    "flash_mode": "qio",
    "psram_type": "opi",
    "hwids": [
      ["0x303A", "0x1001"]
    ],
    "mcu": "esp32s3",
    "variant": "esp32s3"
  },
  "frameworks": ["arduino"],
  "name": "ESP32-S3 N16R8",
  "upload": {
    "flash_size": "16MB",
    "maximum_ram_size": 327680,
    "maximum_size": 16777216,
    "protocol": "esptool",
    "require_upload_port": true,
    "speed": 921600
  },
  "url": "https://www.espressif.com/sites/default/files/documentation/esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf",
  "vendor": "Espressif"
}

TO REPRODUCE

Steps to reproduce the behavior:

1, Create a custom board definition json that attempts to set build variables such as usb_mode, cdc_on_boot, etc.
2. Build.
3. Upload to ESP32-S3.
4. Connect to terminal and inspect ROM messages, seeing that CDC engine is not set as configured.

EXPECTED BEHAVIOUR

A clear and concise description of what you expected to happen.

USB-CDC build options should be set correctly at build time when defined as build variables.

SCREENSHOTS

If applicable, add screenshots to help explain your problem.

platform.ini file
non-working board def
working board def

ADDITIONAL CONTEXT

Add any other context about the problem here.

(Please, remember to close the issue when the problem has been addressed)

[Jason2866]

Any issues with boards.json needs to be addressed from the community via a PR. No action or issue solving here.
https://github.com/pioarduino/platform-espressif32/blob/main/README.md

[nomakewan]

Very well.