Gap
fbuild has no way to apply an ESP-IDF sdkconfig overlay to an ESP32 build. Its own help text says so: "fbuild's own sdkconfig-override layer is a design proposal, not yet implemented (see docs/sdkconfig.md)".
Why FastLED needs it
FastLED ships tools/sdkconfig_for_smallest_fastled.defaults, a size-reduction overlay that sets CONFIG_NEWLIB_NANO_FORMAT=y, CONFIG_LOG_DEFAULT_LEVEL=ESP_LOG_NONE, disables coredump, and more. Its user guide claims about 59 KB of savings on ESP32-S3 Blink. FastLED's measurement script, tests/measure_esp32s3_opt_ins.py, cannot re-verify that claim through fbuild build. The script used to patch the repo-root platformio.ini, which the fbuild compile path never reads, so the "overlay" configs silently measured the baseline (FastLED/FastLED#4570).
Ask
- Honour
board_build.sdkconfig_defaults = <file> and/or pioarduino's custom_sdkconfig for framework = arduino ESP32 environments. With precompiled Arduino libs, this means rebuilding the IDF libs, as pioarduino's hybrid compile does.
- Or fail loudly when those keys are present but unsupported, so callers never get a silent no-op.
Until this lands, FastLED's script refuses the overlay configs with an explicit error that points here.
Gap
fbuild has no way to apply an ESP-IDF sdkconfig overlay to an ESP32 build. Its own help text says so: "fbuild's own sdkconfig-override layer is a design proposal, not yet implemented (see docs/sdkconfig.md)".
Why FastLED needs it
FastLED ships
tools/sdkconfig_for_smallest_fastled.defaults, a size-reduction overlay that setsCONFIG_NEWLIB_NANO_FORMAT=y,CONFIG_LOG_DEFAULT_LEVEL=ESP_LOG_NONE, disables coredump, and more. Its user guide claims about 59 KB of savings on ESP32-S3 Blink. FastLED's measurement script,tests/measure_esp32s3_opt_ins.py, cannot re-verify that claim throughfbuild build. The script used to patch the repo-rootplatformio.ini, which the fbuild compile path never reads, so the "overlay" configs silently measured the baseline (FastLED/FastLED#4570).Ask
board_build.sdkconfig_defaults = <file>and/or pioarduino'scustom_sdkconfigforframework = arduinoESP32 environments. With precompiled Arduino libs, this means rebuilding the IDF libs, as pioarduino's hybrid compile does.Until this lands, FastLED's script refuses the overlay configs with an explicit error that points here.