do-nix-build

#!/usr/bin/env bash

PS4=" [do-nix-build] "
set -eu -o pipefail

if [[ ${ACTIONS_RUNNER_DEBUG:-} == "true" ]]; then
	set -x
fi

NIX_EXPRESSION_FILES=(
	./release.nix
	./default.nix
)

ARGS=( )
STDIN=""

if [[ "${INPUT_NIX_EXPRESSION:-}" != "" ]]; then
	# shellcheck disable=SC2206
	ARGS+=( - )
	STDIN="$INPUT_NIX_EXPRESSION"
else
	if [[ "${INPUT_EXPRESSION_FILE:-}" != "" ]]; then
		ARGS+=( "${INPUT_EXPRESSION_FILE}" )
	else
		for file in "${NIX_EXPRESSION_FILES[@]}"; do
			if test -e "$file"; then
				ARGS+=( "$file" )
				break
			fi
		done
	fi
fi

if [[ "${INPUT_ATTRIBUTES:-}" != "" ]]; then
	for attr in $INPUT_ATTRIBUTES; do
		# shellcheck disable=SC2206
		ARGS+=( --attr "$attr" )
	done
fi

if [[ "${INPUT_NIX_BUILD_EXTRA_ARGUMENTS:-}" != "" ]]; then
	# shellcheck disable=SC2206
	ARGS+=( $INPUT_NIX_BUILD_EXTRA_ARGUMENTS )
fi

if [[ "${INPUT_NIX_PATH:-}" != "" ]]; then
	export NIX_PATH="$INPUT_NIX_PATH"
fi

PS4=" $ "
# Shoving stdin into `nix-build` when not used (via `-`) is not an error.
# Let's use that fact, and always shove in STDIN.
printf "%s" "$STDIN" | (
	set -x
	exec nix-build "${ARGS[@]}" "$@"
)