Stylus @import resolution: does the resolve callback override the paths option?

Stylus 0.64.x resolves @import and @require by checking the importing file's directory, then the paths array passed to stylus.render(), then the resolve callback. When paths and a custom resolve callback are configured together, the intended precedence is not documented: it is unclear whether the first successful callback result short-circuits the remaining paths entries.

This matters for pnpm and yarn workspaces, where node_modules entries are symlinks and resolution reportedly follows the target's realpath — a behavior to confirm against the current release. If a shared .styl library is reachable both via paths and via a workspace link, precedence decides whether a package pulls in one copy of a partial or two, and produces duplicate CSS output.

A related gap: stylus.resolver() offers no option to change the extension search order (.styl, .css, index.styl, index.css) or suppress index lookup, so the callback cannot fully express desired import semantics.

1. With paths and resolve both set, what precedence is intended, and does a successful callback result stop the paths search?
2. Does realpath resolution apply to paths entries too, and is there a supported way to pin resolution to the symlink location?
3. Is any optional-import mechanism documented, or does failed resolution always throw for both @import and @require?