We've previously had the syntax and representation of module source
addresses pretty sprawled around the codebase and intermingled with other
systems such as the module installer.
I've created a factored-out implementation here with the intention of
enabling some later refactoring to centralize the address parsing as part
of configuration decoding, and thus in turn allow the parsing result to
be seen by other parts of Terraform that interact with configuration
objects, so that they can more robustly handle differences between local
and remote modules, and can present module addresses consistently in the
UI.
Martin Atkins