Check for drift between .template files and generated files #18

	name: CI

	on:
	pull_request:
	branches:
	- main

	jobs:
	check-drift:
	runs-on: ubuntu-latest
	env:
	REPO: ${{ github.event.repository.name }}

	steps:
	- name: Checkout repository
	uses: actions/checkout@v4

	- name: Install Rust toolchain
	uses: dtolnay/rust-toolchain@stable

	- name: Install cargo-generate
	uses: taiki-e/install-action@v2
	with:
	tool: cargo-generate

	- name: Retain a copy of every generated file
	run: \|
	for template_file in $(find . -type f -name '*.template'); do
	generated_file="${template_file%.template}"
	if [[ -f "{$generated_file}" ]]; then
	# Keep a copy to diff with the output of the next step.
	cp "${generated_file}" "${generated_file}.check"
	fi
	done

	- name: Generate from templates
	run: \|
	# Note: we use cargo-generate itself here as our wrapping of the cargo-generate library
	# does not allow us to do useful things like --allow-commands and use local templates.
	cargo generate --path . --name '${{ env.REPO }}' --allow-commands

	- name: Check for drift between templates and generated files
	run: \|
	for check_file in $(find '${{ env.REPO }}' -type f -name '*.check'); do
	generated_file="${check_file%.check}"
	if ! diff "${check_file}" "${generated_file}"; then
	echo "File ${generated_file} has drift from ${generated_file}.template:"
	echo "::error file=${generated_file}::Template drift detected."
	exit 1
	fi
	done

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