#QMK Breaking Change - 2019 Aug 30

Four times a year QMK runs a process for merging Breaking Changes. A Breaking Change is any change which modifies how QMK behaves in a way that is incompatible or potentially dangerous. We limit these changes to 4 times per year so that users can have confidence that updating their QMK tree will not break their keymaps.

This document marks the inaugural Breaking Change merge. A list of changes follows.

#Core code formatting with clang-format

• All core files (drivers/, quantum/, tests/, and tmk_core/) have been formatted with clang-format
• A travis process to reformat PRs on merge has been instituted
• You can use the new CLI command qmk cformat to format before submitting your PR if you wish.

#LUFA USB descriptor cleanup

• Some code cleanups related to the USB HID descriptors on AVR keyboards, to make them easier to read and understand
• More information: see https://github.com/qmk/qmk_firmware/pull/4871
• No behaviour changes anticipated and no keymaps modified

#Migrating ACTION_LAYER_MOMENTARY() entries in fn_actions to MO() keycodes

• fn_actions is deprecated, and its functionality has been superseded by direct keycodes and process_record_user()
• The end result of removing this obsolete feature should result in a decent reduction in firmware size and code complexity
• All keymaps affected are recommended to switch away from fn_actions in favour of the custom keycode and macro features

#Update Atreus to current code conventions

• Duplicate include guards have bypassed the expected header processing behavior
• All keymaps affected are recommended to remove duplication of <keyboard>/config.h to <keyboard>/keymaps/<user>/config.h and only provide overrides at the keymap level

#Backport changes to keymap language files from ZSA fork

• Fixes an issue in the keymap_br_abnt2.h file that includes the wrong source (keymap_common.h instead of keymap.h)
• Updates the keymap_swedish.h file to be specific to swedish, and not just "nordic" in general.
• Any keymaps using this will need to remove NO_* and replace it with SE_*.

#Update repo to use LUFA as a git submodule

• /lib/LUFA removed from the repo
• LUFA set as a submodule, pointing to qmk/lufa
• This should allow more flexibility with LUFA, and allow us to keep the sub-module up to date, a lot more easily. It was ~2 years out of date with no easy path to fix that. This prevents that from being an issue in the future

#Migrating ACTION_BACKLIGHT_*() entries in fn_actions to BL_ keycodes

• fn_actions is deprecated, and its functionality has been superseded by direct keycodes and process_record_user()
• All keymaps using these actions have had the relevant KC_FN* keys replaced with the equivalent BL_* keys
• If you currently use KC_FN* you will need to replace fn_actions with the custom keycode and macro features

#Remove KC_DELT alias in favor of KC_DEL

• KC_DELT was a redundant, undocumented alias for KC_DELETE
• It has been removed and all its uses replaced with the more common KC_DEL alias
• Around 90 keymaps (mostly for ErgoDox boards) have been modified as a result