Check for drift between .template files and generated files #30

	name: CI

	on:
	pull_request:
	branches:
	- main

	jobs:
	# Compare committed files with those generated from templates to ensure no differences occur.
	check-generated-files:
	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 pre-generated files
	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 repository
	run: \|
	# Note: we use cargo-generate itself here as bevy_cli's 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 "${REPO}" --allow-commands

	- name: Diff generated files
	run: \|
	change_detected=false

	for check_file in $(find "${REPO}" -type f -name '*.check'); do
	generated_file="${check_file%.check}"
	if ! diff "${check_file}" "${generated_file}" > /dev/null ; then
	echo "File ${generated_file} has changed from ${generated_file}.template:"
	diff "${check_file}" "${generated_file}" \|\| true
	echo "::error file=${generated_file}::Template change detected."
	change_detected=true
	fi
	done

	if [[ "${change_detected}" == true ]]; then
	exit 1
	fi

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