I'm working on packaging for the [https://github.com/rust-lang/rust/ Rust] compiler and its [https://github.com/rust-lang/cargo/ Cargo] build system. Both of these are self-bootstrapped, so they need to use pre-built binaries to get going. To test and demonstrate, on [https://copr.fedorainfracloud.org/coprs/jistone/rust/builds/ my COPR] I have successfully built both using pre-built binaries, then rebuilt with source-only srpms.

These should be self-sustaining once they get going, but there may still be a need to redo bootstrapping occasionally. For instance, if a library we depend on is changing its SONAME, then we won't be able to install the old rust/cargo (linked against the old library) to help build against the new library-devel, unless that library is nice enough to provide compat libs. Repeating the bootstrap procedure seems like the easiest way out of that.

Anyway, please consider an exception to the no-prebuilt-binaries rule for these packages.

• [https://bugzilla.redhat.com/show_bug.cgi?id=1356907 open review for Rust]
• [https://bugzilla.redhat.com/show_bug.cgi?id=1357749 open review for Cargo]
• [https://fedoraproject.org/wiki/Changes/RustCompiler proposed self-contained change]