# This action periodically merges base branches into staging branches.

# This is done to

# * prevent conflicts or rather resolve them early

# * make all potential breakage happen on the staging branch

# * and make sure that all major rebuilds happen before the staging

# branch get’s merged back into its base branch.

name: "Periodic Merges (24h)"

on:

schedule:

# * is a special character in YAML so you have to quote this string

# Merge every 24 hours

- cron: '0 0 * * *'

workflow_dispatch:

permissions: {}

defaults:

run:

shell: bash

jobs:

periodic-merge:

if: github.repository_owner == 'NixOS' || github.event_name == 'workflow_dispatch'

strategy:

# don't fail fast, so that all pairs are tried

fail-fast: false

# certain branches need to be merged in order, like master->staging-next->staging

# and disabling parallelism ensures the order of the pairs below.

max-parallel: 1

matrix:

pairs:

- from: release-25.11

into: staging-next-25.11

- from: staging-next-25.11

into: staging-25.11

- from: release-25.11

into: staging-nixos-25.11

- from: release-26.05

into: staging-next-26.05

- from: staging-next-26.05

into: staging-26.05

- from: release-26.05

into: staging-nixos-26.05

- name: merge-base(master,staging) → haskell-updates

from: master staging

into: haskell-updates

uses: ./.github/workflows/periodic-merge.yml

with:

from: ${{ matrix.pairs.from }}

into: ${{ matrix.pairs.into }}

name: ${{ matrix.pairs.name || format('{0} → {1}', matrix.pairs.from, matrix.pairs.into) }}

secrets:

NIXPKGS_CI_APP_PRIVATE_KEY: ${{ secrets.NIXPKGS_CI_APP_PRIVATE_KEY }}

# Resets the target branch of the current haskell-updates PR.

# This makes GitHub hide all the commits that are already part of staging and gives us a much clearer PR view.

haskell-updates:

needs: periodic-merge

runs-on: ubuntu-slim

permissions:

pull-requests: write

steps:

- name: Find PR and update target branch

uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0

with:

script: |

// There will at most be a single haskell-updates PR anyway, so no need to paginate.

await Promise.all(

(

await github.rest.pulls.list({

...context.repo,

state: 'open',

head: `${context.repo.owner}:haskell-updates`,

})

).data.map((pr) =>

github.rest.pulls.update({

...context.repo,

pull_number: pr.number,

// Just updating to the same branch to trigger a UI update.

// This is staging most of the time, but could be staging-next in rare cases.

base: pr.base.ref,

}),

),

)