#Breaking Changes

This document describes QMK's Breaking Change process. A Breaking Change is any change which modifies how QMK behaves in a way that in incompatible or potentially dangerous. We limit these changes so that users can have confidence that updating their QMK tree will not break their keymaps.

This also includes any keyboard moves within the repository.

The breaking change period is when we will merge PR's that change QMK in dangerous or unexpected ways. There is a built-in period of testing so we are confident that any problems caused are rare or unable to be predicted.

#What has been included in past Breaking Changes?

• 2022 Nov 26
• 2022 Aug 27
• 2022 May 28
• 2022 Feb 26
• 2021 Nov 27
• 2021 Aug 28
• 2021 May 29
• 2021 Feb 27
• 2020 Nov 28
• 2020 Aug 29
• 2020 May 30
• 2020 Feb 29
• 2019 Aug 30

#When is the next Breaking Change?

The next Breaking Change is scheduled for February 26, 2023.

#Important Dates

• 2022 Nov 26 - develop is tagged with a new release version. Each push to master is subsequently merged to develop by GitHub actions.
• 2023 Jan 29 - develop closed to new PR's.
• 2023 Jan 29 - Call for testers.
• 2023 Feb 12 - Last day for merges -- after this point develop is locked for testing and accepts only bugfixes
• 2023 Feb 19 - develop is locked, only critical bugfix PR's merged.
• 2023 Feb 24 - master is locked, no PR's merged.
• 2023 Feb 26 - Merge develop to master.
• 2023 Feb 26 - master is unlocked. PR's can be merged again.

#What changes will be included?

To see a list of breaking change candidates you can look at the breaking_change label. New changes might be added between now and when develop is closed, and a PR with that label applied is not guaranteed to be merged.

If you want your breaking change to be included in this round you need to create a PR with the breaking_change label and have it accepted before develop closes. After develop closes no new breaking changes will be accepted.

Criteria for acceptance:

• The PR is complete and ready to merge
• The PR has a ChangeLog file describing the changes under <qmk_firmware>/docs/Changelog/20221126.
  • This should be in Markdown format, with a name in the format PR12345.md, substituting the digits for your PR's ID.
  • One strong recommendation that the ChangeLog document matches the PR description on GitHub, so as to ensure traceability.

#Checklists

This section documents various processes we use when running the Breaking Changes process.

#4 Weeks Before Merge

• develop is now closed to new PR's, only fixes for current PR's may be merged
• Post call for testers: message @Breaking Changes Updates on #qmk_firmware in Discord:
  • @Breaking Changes Updates -- Hey folks, last day for functional PRs to be raised against qmk_firmware for this breaking changes cycle is today.

#2 Weeks Before Merge

• develop is now closed to existing PR merges, only bugfixes for previous merges may be included
• Post call for testers: message @Breaking Changes Updates on #qmk_firmware in Discord.
  • @Breaking Changes Updates -- Hey folks, last day for functional PRs to be merged into qmk_firmware for this breaking changes cycle is today. After that, we're handling bugfixes only.

#1 Week Before Merge

• develop is now closed to PR merges, only critical bugfixes may be included
• Announce that master will be closed from <2 Days Before> to -- message @Breaking Changes Updates on #qmk_firmware in Discord:
  • @Breaking Changes Updates -- Hey folks, last day for functional PRs to be merged into qmk_firmware for this breaking changes cycle is today. After that, we're handling bugfixes only.

#2 Days Before Merge

• master is now closed to PR merges
• Announce that master is closed for 2 days
  • @Breaking Changes Updates -- Hey folks, the master branch of qmk_firmware is now locked for the next couple of days while we prepare to merge the newest batch of changes from develop.

#Day Of Merge

• qmk_firmware git commands
  • git checkout develop
  • git pull --ff-only
  • Edit readme.md
    • Remove the notes about develop
  • Roll up the ChangeLog into one file.
  • git commit -m 'Merge point for <DATE> Breaking Change'
  • git push upstream develop
• GitHub Actions
  • Create a PR for develop
  • Turn off 'Automatically delete head branches' for the repository -- confirm with @qmk/directors that it is done before continuing
• qmk_firmware git commands
  • git checkout master
  • git pull --ff-only
  • git merge --no-ff develop
  • git tag <next_version> # Prevent the breakpoint tag from confusing version incrementing
  • git push upstream <next_version>
  • git push upstream master

#Post-merge operations

#Updating the develop branch

This happens immediately after the previous develop branch is merged to master.

• qmk_firmware git commands

  • git checkout master
  • git pull --ff-only
  • git checkout develop
  • git pull --ff-only
  • git merge --no-ff master
  • Edit readme.md
    • Add a big notice at the top that this is a testing branch. See previous revisions of the develop branch.
    • Include a link to this document
  • git commit -m 'Branch point for <DATE> Breaking Change'
  • git tag breakpoint_<YYYY>_<MM>_<DD>
  • git push upstream breakpoint_<YYYY>_<MM>_<DD>

• All submodules under lib now need to be checked against their QMK-based forks:

  • git submodule foreach git log -n1
  • Validate each submodule SHA1 matches the qmk fork, e.g. for ChibiOS:
    • Go to qmk/ChibiOS
    • Compare the commit hash in the above output to the commit hash in the repository
    • If there's a mismatch, that repository needs to have its master branch updated to match (otherwise Configurator won't work):
      • cd lib/chibios
      • git fetch --all
      • git checkout master
      • git reset --hard <commit hash>
      • git push origin master --force-with-lease

• Announce that both master and develop are now unlocked -- message @Breaking Changes Updates on #qmk_firmware in Discord:

  • @Breaking Changes Updates -- Hey folks, develop has now been merged into master -- newest batch of changes are now available for everyone to use!

• (Optional) update ChibiOS + ChibiOS-Contrib on develop

#Set up Discord events for the next cycle

• Update this file with the new dates: docs/breaking_changes.md
• Create Events on the QMK Discord - "Somewhere Else" => "GitHub":
  • Event #1:

    Field	Value
    Topic	Last develop functionality PRs to be raised
    Start Date	((5 weeks before merge)), 12:00am
    End Date	((4 weeks before merge)), 12:00am
    Description	This is the last window for functional PRs to be raised against develop for the current breaking changes cycle. After ((4 weeks before merge)), any new PRs targeting develop will be deferred to the next cycle.

  • Event #2:

    Field	Value
    Topic	Last develop functionality PRs to be merged
    Start Date	((4 weeks before merge)), 12:00am
    End Date	((2 weeks before merge)), 12:00am
    Description	This is the last window for functional PRs to be merged into develop for the current breaking changes cycle. After ((2 weeks before merge)), only bugfix PRs targeting develop will be considered for merge.

  • Event #3:

    Field	Value
    Topic	develop closed for merges
    Start Date	((2 weeks before merge)), 12:00am
    End Date	((day of merge)), 12:00am
    Description	This is the deadline for functionality bugfix PRs to be merged into develop for the current breaking changes cycle. After ((1 week before merge)), only critical bugfix PRs targeting develop will be considered for merge.

  • Event #4:

    Field	Value
    Topic	master closed for merges
    Start Date	((2 days before merge)), 12:00am
    End Date	((day of merge)), 12:00am
    Description	This is the period that no PRs are to be merged to master, so that the merge of develop into master is stable.

  • Event #5:

    Field	Value
    Topic	develop merges to master
    Start Date	((day of merge)), 12:00am
    End Date	((day of merge)), 11:45pm
    Description	At some point, QMK will merge develop into master and everyone will be able to reap the benefits of the newest batch of functionality.