On Mon, Nov 18, 2019 at 6:58 PM William Brown <wbrown@suse.de> wrote:
Hi,
Recently I've been trying to package some utilities for SUSE and Fedora via OBS that are written in Rust. I'm running into a bit of a problem though.
Rust as a language has a very aggressive release cycle compared to what we expect on a platform like SUSE - 6 weeks (https://github.com/rust-lang/rust/blob/master/RELEASES.md). In each cycle Rust releases new features, and despite the core language being "stable" and safe (which is great!) new features tend to be used very rapidly by library authors. For example the release from Version 1.34.0 (2019-04-11) contains convert::TryFrom, which is now in use by a large number of libraries.
Rust also has an (unfortunate) requirement that you are essentially forced to use cargo which is a build and dependency management tool. Cargo is extremely opinionated and inflexible which makes it difficult to use. However as it's also a dependency management tool, this has encouraged an npm-style ecosystem of dependencies to spring up on https://crates.io/ - and it's effectively the only way to use libraries in Rust. But additionally, it's promoted a system where a library may have a large number of small dependencies too.
Due to the fast release cycle, developers aggressively using new features, and the npm style micro dependency system we have a recipe for problems - if you are not using the latest stable compiler, it's extremely likely that your libraries, or their dependents may not build on your project. Which is exactly the issue I have run into where rust on fedora 30 and opensuse leap 15.1 are simply too old to support the features that have been used in the last 6 months by library developers.
Which leads me to the question of "what to do".
* I don't believe it's feasible to ask Rust to "slow down". It's just not going to happen, and they will keep adding features that people will "want" to use. * We can't expect people *not* to update their dependencies in projects as that would prevent security updates being included. So we have to accept projects that will use "latest and greatest" complier features somewhere in their dependency graph. * Which leaves distros (like us) speeding up our rust compiler cycle somehow.
For opensuse I can probably do something like adding devel:languages:rust as a respository to my project. Would this strategy be viable on SLE? What about for projects which we want to expose packages for fedora or other? Are we able to have toolchains move faster than our base system?
I'm really looking for ideas on how we can sustainably use rust projects within the governance and social constraints that exist in the space. Ideas?
Unfortunately, SUSE rust compiler packaging spec isn't the same as the RH/Fedora/Mageia one, so essentially it takes double the work to keep things up to date everywhere. If we integrated the SUSE support bits into the RH/Fedora/Mageia rust packaging spec, that could make things easier. It's not exactly the highest thing on my list to look into right now, though... That said, Fedora and Mageia update the Rust compiler within a week of a new stable compiler release. As of right now, Fedora 29 and higher all have Rust 1.39.0. CentOS/RHEL 7 will receive Rust 1.39.0 soon too[1]. Crate packaging and macros are completely in sync among Fedora, Mageia, and openSUSE. These are provided by the rust-packaging and rust-srpm-macros packages. This code is pretty much the same across all three distributions. I find the process of shipping updates to SUSE distributions thoroughly annoying and unappealing, so I don't personally do anything to target anything other than Tumbleweed. The process is too slow because it's often bottlenecked on either legal-auto or the all-too-tiny number of reviewers for SRs and MRs. This is also true for Tumbleweed, but it seems to be somewhat faster there. I'd be more interested in helping ship updates to Leap if we could make this process less awful. [1]: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2019-037907db2c -- 真実はいつも一つ！/ Always, there's only one truth! -- To unsubscribe, e-mail: opensuse-packaging+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-packaging+owner@opensuse.org