Demo <FEATURE>_SUPPORTED flags working with post_keymap

build_keyboard.mk

@@ -286,16 +286,17 @@ ifneq ("$(wildcard $(KEYBOARD_PATH_5)/post_config.h)","")
     POST_CONFIG_H += $(KEYBOARD_PATH_5)/post_config.h
 endif
 
+# Disable features that a keyboard doesn't support
+# Process after keyboard, userspace and keymap, but before post_keymap
+-include disable_features.mk
+
 # Userspace makefile second pass
 -include $(USER_PATH)/post_keymap.mk
 # Userspace config.h first pass
 ifneq ("$(wildcard $(USER_PATH)/config.h)","")
     CONFIG_H += $(USER_PATH)/config.h
 endif
 
-# Disable features that a keyboard doesn't support
--include disable_features.mk
-
 # Object files directory
 #     To put object files in current directory, use a dot (.), do NOT make
 #     this an empty or blank macro!

keyboards/maartenwut/wasdat/rules.mk

@@ -24,6 +24,7 @@ SLEEP_LED_ENABLE = no       # Breathing sleep LED during USB suspend
 # if this doesn't work, see here: https://github.com/tmk/tmk_keyboard/wiki/FAQ#nkro-doesnt-work
 NKRO_ENABLE = yes           # USB Nkey Rollover
 BACKLIGHT_ENABLE = no       # Enable keyboard backlight functionality
+BACKLIGHT_SUPPORTED = no
 RGBLIGHT_ENABLE = no        # Enable keyboard RGB underglow
 MIDI_ENABLE = no            # MIDI support
 BLUETOOTH_ENABLE = no       # Enable Bluetooth with the Adafruit EZ-Key HID

users/konstantin/my_backlight.c

@@ -0,0 +1 @@
+This will error out if it gets included in the build.

users/konstantin/post_keymap.mk

@@ -12,3 +12,14 @@ endif
 ifneq (,$(filter yes,$(UNICODE_ENABLE) $(UNICODEMAP_ENABLE)))
     SRC += unicode.c
 endif
+# Context: The user konstantin has `BACKLIGHT_ENABLE = yes` in their userspace,
+# and is trying to build `make maartenwut/wasdat:konstantin`, a keyboard that
+# has `BACKLIGHT_SUPPORTED = no` declared.
+# If everything works correctly, at this point in the build (post_keymap.mk),
+# the supported flag will have overridden the enable flag and set it to no, so
+# the .c file will NOT be included and the build will finish successfully.
+# The keyboard's "backlight not supported" flag is respected by default,
+# without requiring extra checks in the makefile.
+ifeq ($(strip $(BACKLIGHT_ENABLE)), yes)
+    SRC += my_backlight.c
+endif

users/konstantin/rules.mk

@@ -9,7 +9,7 @@ TAP_DANCE_ENABLE   = yes
 UNICODEMAP_ENABLE  = yes
 
 # Keyboard-specific feature defaults
-BACKLIGHT_ENABLE   = no
+BACKLIGHT_ENABLE   = yes  # Enabled in userspace, but keyboard has BACKLIGHT_SUPPORTED = no
 RGBLIGHT_ENABLE    = no
 RGB_MATRIX_ENABLE  = no