Missing dependencies do not raise an error

I have in my project.info graphs explicitly enabled, yet if graphviz is not installed, the graphs are not build and no error is raised.
An info is printed, but I normally don't check CI logs.

While it might be nice for quick testing, it is rather annoying for CI.

Does it make sense to add an option to error on missing, optional dependencies?
Should this always be an error, but the error message includes an option to disable generating graphs?