This particular issue is resolved in 6.3.0, but it can be resolved in any version by just setting the public path. What is the rationale for being so averse to it?
There is a reasonare reasons why it is a near universal requirement of all major popular frameworks. See 6.3.0 release notes for more on this:
The only case where a public path should be an issue is if you are distributing a theme (since you can’t control the public path of the wordpress that is using it). If you’re distributing a theme you have earned a pardon.
To re-iterate what @kellymears said, the proper solution to this is to set the public path. This is now a requirement moving forward in Sage 10, and was always required in Sage 9. See the PR or the latest Bud config in Sage 10 for an example.
/**
* URI of the `public` directory
*/
.setPublicPath("/app/themes/sage/public/");