only allow one running build job #1694

	on: [push, pull_request]

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}

	name: Build

	jobs:
	build:
	runs-on: ubuntu-latest

	env:
	mailmap: ${{ secrets.MAILMAP }}

	steps:
	- name: Checkout ⬇️
	uses: actions/checkout@v3
	with:
	fetch-depth: 0 # we need the commit history for authors

	- name: Install Nix ❄️
	uses: cachix/install-nix-action@v20

	- name: Set up Cachix ♻️
	uses: cachix/cachix-action@v12
	with:
	name: 1lab
	authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}

	- name: Build the Shakefile 🧰
	run: \|
	hash=$(nix-build -A shakefile --no-out-link)
	hash=${hash#/nix/store/} hash=${hash%%-*}
	echo "shake_version=$hash" >> "$GITHUB_ENV"

	- name: Cache _build ♻️
	uses: actions/cache@v3
	with:
	path: _build
	key: shake-4-${{ env.shake_version }}-${{ github.run_id }}
	restore-keys: shake-4-${{ env.shake_version }}-

	- name: Build 🛠️
	run: \|
	echo "$mailmap" > .mailmap
	nix-shell --arg interactive false --run "$build_command"
	env:
	NIX_BUILD_SHELL: bash
	build_command: \|
	set -eu
	1lab-shake -j all
	eval "$installPhase"

	- name: Upload site ⬆️
	uses: actions/upload-pages-artifact@v1
	with:
	path: _build/site
	retention-days: 1

	deploy:
	needs: build
	if: ${{ github.ref_name == 'main' }}

	permissions:
	pages: write
	id-token: write

	environment:
	name: github-pages
	url: ${{ steps.deployment.outputs.page_url }}

	runs-on: ubuntu-latest
	steps:
	- name: Deploy 🚀
	id: deployment
	uses: actions/deploy-pages@v1

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