```toml [dependencies] bitflags  = "~0.7" ansi_term = { version = "~0.9.0",  optional = true } term_size = { version = "~0.2.0",  optional = true } libc      = { version = "~0.2.9",  optional = true } [features] default   = ["color", "wrap_help"] color     = ["ansi_term", "libc"] wrap_help = ["libc", "term_size"] ``` Since we are packaging source code, -devel package will have `Requires: crate(bitflags)`. But applications (which are built out of this sources statically) can request features which this source is exposing and it means that it should pull additional dependencies. Syntax for such dependencies is like: ```toml [dependencies] clap = { version = "2.19.2", features = ["yaml"] } ``` Obviously, first thing which is coming to mind is to specify provides for features and use rich dependencies for requirements, something like: ``` Provides: crate(clap) Provides: crate(clap)(color) Requires: ((crate(ansi_term) and crate(libc)) if crate(clap)(color)) Provides: crate(clap)(wrap_help) Requires: ((crate(libc) and crate(term_size)) if crate(clap)(wrap_help)) ``` But it doesn't work since it works the RPM thinks that crate(clap)(xxx) is going to be installed (since it's provided by same package) so it requires other packages to be installed as well which is something not what we want. Probably for now sane way would be just require all optional packages to cover *all* features which package provides, but it means that builds will be slow because they would need to pull a lot of packages always. P.S. I omit version stuff to make examples more easy. P.P.S. ignore `default` feature for now since I'm not sure how exactly it works in rust/cargo ecosystem at this moment. -- -Igor Gnatenko