build: Add CI check that image-data and workflow lists are in sync #1

	# Require that images-data.json and the list of images in
	# push-docker-images.yaml are kept in sync.

	name: Check that image lists are in sync
	on:
	# To make this a required check, has to run even if no relevant
	# config changes. So can't filter on paths here.
	pull_request:
	defaults:
	run:
	shell: bash # making this explicit opts into -e -o pipefail
	jobs:
	check-image-list-sync:
	runs-on: ubuntu-latest
	steps:
	- name: Checkout
	uses: actions/checkout@v4
	with:
	fetch-depth: 1

	- name: Install Python
	uses: actions/setup-python@v5
	with:
	python-version: '3.12'

	- name: Detect and report
	run: \|
	python3.12 -m venv --upgrade-deps ./deps-venv
	pip=./deps-venv/bin/pip

	$pip install --quiet jq yq
	jq=./deps-venv/bin/yq
	yq=./deps-venv/bin/yq

	json_src=images-data.json
	workflow_src=.github/workflows/push-docker-images.yml

	cat json_src \
	\| jq '.[].name' -r
	\| sort \
	> names-in-json.lst

	cat "$workflow_src" \
	\| yq '.on.workflow_dispatch.inputs.image_to_build.options[]' -r \
	\| sort \
	> options-in-workflow.lst

	set +e
	diff_out=$(diff -u0 names-in-json.lst options-in-workflow.lst)
	diff_exit=$?
	set -e

	echo
	echo
	case $diff_exit in
	0)
	echo "Image lists match" \| tee -a "$GITHUB_STEP_SUMMARY"
	exit 0
	;;
	1)
	tee -a "$GITHUB_STEP_SUMMARY" <<MESSAGE
	Mismatch in image name lists between `${json_src}` and `${workflow_src}`:
	```
	$diff_out
	```
	MESSAGE
	exit 1
	;;
	*)
	tee -a "$GITHUB_STEP_SUMMARY" <<MESSAGE
	Error computing diff:
	```
	$diff_out
	```
	Exit code: $diff_exit
	MESSAGE
	;;
	esac

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