Upstream draft: esp32 build fails on include dirs ESP-IDF declares but never creates (patch 0018) #36

Overlay patch 0018 (#35) works around a MicroPython esp32 build bug that upstream has too. Below is a draft issue for micropython/micropython, for a maintainer to post or edit; it isn't posted. Our upstream posture is case by case: patch our overlay and draft upstream.

Title: esp32: build fails when a user C module links an IDF component that declares a non-existent include directory

Port, board and/or hardware: esp32, ESP32_GENERIC_S3, ESP-IDF v5.5.4 (fresh clone)

MicroPython version: v1.29.0, and master as of 2026-10-06

Reproduction: build any ESP32-S3 firmware with a user C module that links an ESP-IDF component through target_link_libraries(usermod_x INTERFACE idf::esp_driver_cam) (or idf::esp_lcd), against a fresh clone of ESP-IDF v5.5.4.

Expected: it builds.

Observed: configure fails: Include directory '<IDF>/components/esp_hw_support/mspi_timing_tuning/port/esp32s3/include' is not a directory.

Why: ESP-IDF v5.5.4's esp32s3 mspi_timing_tuning port adds include to its interface include directories, but no files are tracked there, so git never creates the directory. py/usermod.cmake gathers include directories transitively from libraries linked by user modules, so that path lands in MICROPY_INC_USERMOD. ports/esp32/esp32_common.cmake then passes it to idf_component_register(INCLUDE_DIRS ...), which checks that each one exists. A checkout that was once at an older ESP-IDF tag keeps the empty directory and hides the problem.

Fix we carry: in esp32_common.cmake, filter MICROPY_INC_USERMOD to directories that exist (keeping generator expressions) before idf_component_register(). It's patch 0018 in https://github.com/PyDevices/micropython-pydevices/tree/main/patches/micropython.

After posting, add the link here and in the patch header. Drop the patch when upstream fixes it.