Bash: what delimiter to use for this string to array conversion to work? (Laravel/dotenv/Sail/Docker Compose)

Question

Laravel Sail should support multiple docker-compose files by configuring them in a dotenv file (.env).

The line in my .env file...

SAIL_FILES='docker-compose.yml:docker-compose-arm.yml'

The part of Sail that handles multiple sail files (I can't/shouldn't edit this)

if [ -n "$SAIL_FILES" ]; then
    # Convert SAIL_FILES to an array...
    SAIL_FILES=("${SAIL_FILES//:/ }")

    for FILE in "${SAIL_FILES[@]}"; do
        if [ -f "$FILE" ]; then
            DOCKER_COMPOSE+=(-f "$FILE")
        else
            echo "${BOLD}Unable to find Docker Compose file: '${FILE}'${NC}" >&2

            exit 1
        fi
    done
fi

I've tried a few different delimiters (comma, spaces, .etc). It seems simple but I can't get it to work. I can't understand how SAIL_FILES=("${SAIL_FILES//:/ }") performs the array conversion (I'm new to Bash).

I've recreated the issue here which should simply echo each filename on a new line.

This doesn't seem to be documented anywhere on Laravel.

Thanks.

Answer 1

Double quoting prevents word-splitting. If you want word-splitting to happen, don't quote:

SAIL_FILES=(${SAIL_FILES//:/ })

You can also use $IFS to split the string without substitution:

IFS=: SAIL_FILES=($SAIL_FILES)