Make build dependent on detecting changes on the branch #17

	name: Docker Build

	on:
	push:
	# Builds should happen on feature branches
	# Only successfully tested builds should be merged to main
	# We don't want to rebuild after testing and verifying
	branches-ignore:
	- 'main'
	paths:
	- '.github/workflows/dockerBuild.yml'
	- 'docker/*'
	workflow_dispatch:

	jobs:
	dockerBuild:
	runs-on: ubuntu-latest
	strategy:
	fail-fast: false
	matrix:
	platform:
	- 'arch'
	env:
	DockerRepository: ghcr.io/${{ github.repository_owner }}

	steps:
	- uses: actions/checkout@v4

	- name: Fetch main
	run: \|
	git remote set-branches --add origin main
	git fetch --depth 1

	- name: Check for changes
	id: diff
	run: \|
	set +e
	git diff --exit-code --no-patch origin/main docker/nas2d-${{ matrix.platform }}.* ; echo "modified=$?" >> $GITHUB_OUTPUT

	- name: Docker build
	if: ${{ fromJSON(steps.diff.outputs.modified) }}
	run: make -C docker build-image-${{ matrix.platform }}

	- name: Docker login
	if: ${{ fromJSON(steps.diff.outputs.modified) }}
	run: echo "${{ secrets.GITHUB_TOKEN }}" \| docker login ghcr.io --username "${{ github.repository_owner }}" --password-stdin

	- name: Docker push
	if: ${{ fromJSON(steps.diff.outputs.modified) }}
	run: make -C docker push-image-${{ matrix.platform }}

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