build

fix GitHub Actions error handling #394

	name: build
	on:
	pull_request:

	jobs:
	run:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v3
	with:
	# checkout the whole repo history
	fetch-depth: 0

	- name: Set up Go
	uses: actions/setup-go@v5
	with:
	go-version: '1.20'

	- name: Setup Docker BuildX
	uses: docker/setup-buildx-action@v2
	with:
	version: https://github.com/docker/buildx.git#master

	- name: Build
	run: \|
	mkdir output
	exit_status=0

	# only build images which are new or modified since the base
	git diff --name-only --no-renames --diff-filter=AM "${{ github.event.pull_request.base.sha }}" \
	\| grep Dockerfile$ \
	\| xargs dirname \
	\| xargs -n1 basename \
	\| go run breadmaker.go --docker \|\| exit_status=$?

	[ $exit_status -gt 0 ] && echo ::error::Build failed!

	shopt -s nullglob
	for file in output/*.log; do
	name=${file#output/}
	name=${name%.log}
	echo "::group::$name"
	cat "$file"
	echo "::endgroup::"
	done

	(exit $exit_status)

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