Makefile variable as prerequisite

Question

In a Makefile, a deploy recipe needs a environment variable ENV to be set to properly execute itself, whereas others don\'t care, e.g.:

Answer 1

You can use ifdef instead of a different target.

.PHONY: deploy
deploy:
    ifdef ENV
        rsync . $(ENV).example.com:/var/www/myapp/
    else
        @echo 1>&2 "ENV must be set"
        false                            # Cause deploy to fail
    endif