| > AFAIK there is no other distro that does this, what they do is that they would download crates from crates.io (`cargo vendor` is a command that does this automatically) and build against that. AFAIK, most traditional distributions do that, not just Debian. They consider it important that software can be rebuilt, even in the far future, with nothing more than a copy of the distribution's binary and source packages. Doing anything which depends on network access during a build of the software is verboten (and AFAIK the automated build hosts block the network to enforce that requirement). Keep also in mind that these distributions are from before our current hyper-connected time; it was common for a computer to be offline most of the time, and only dial up to the Internet when necessary. You can still download full CD or DVD sets containing all of the Debian binaries and source code, and these should be enough to rebuild anything from that distribution, even on an air-gaped computer. > Secondly, even if they have to use crates from their repository, I don't understand what's so hard to just have multiple versions of the same crate? That will solve the problem too. That is often done for C libraries; for instance, Debian stable has both libncurses5 and libncurses6 packages. But it's a lot of work, since for technical reasons, each version has to be an independent package with a separate name, and at least for Debian, each new package has to be reviewed by the small ftpmaster team before being added to the distribution. I don't know whether there's anything Rust-specific that makes this harder (for C libraries, the filenames within the library packages are different, and the -dev packages with the headers conflict with each other so only one can be installed at a time). There's also the issue that having multiple versions means maintaining multiple versions (applying security fixes and so on). |
This is the most important part. Debian LTS maintains packages for 5 years. Canonical takes Debian sources, and offers to maintain their LTS for 10 years. Red Hat also promises 10 years of support. They don't want anything in the core part of their stable branches that they can't promise to maintain for the next 5-10 years, when they have no assurance that upstream will even exist that long.
If you want to move fast and break things, that's also fine. Just build and distribute your own .deb or .rpm. No need to bother distro maintainers who are already doing so much thankless work.