Relative url paths

[am11]

According to https://github.com/sass/node-sass#imagepath, whatever path is set to imagePath, it will be prepended to output for image-url(..), which is; url(..).

Now that we are sending outPath to downstream (so it handles sourceMaps related path correctly), shouldn't we make it practice to resolve image URLs w.r.t. generated CSS file location (so implementers don't have to post-process these using separate AST, like this)?

Reproduction steps: less/less.js#2084 (comment) (just replace less with scss).

@andrew, @mgreter,

• Does it conflicts with SASS specs? If it does, solution like Custom-output-path-aware relative-URLs less/less.js#2084 (comment) would do the trick.
• Is it the upstream (libsass) issue?

[am11]

This issue has been moved to: sass/libsass#532.