Rust nightly vs beta version

Question

I am trying to understand the difference between rust nightly and the beta version. They both seem to be suitable for cases when one needs to use experimental features, but I can't really find the exact difference.

Piccalilli

Just to nitpick... If one was better than the other then you wouldn't need one of them. Because it would be worse. If your question is about differences then it seems okay, but if you want to know which is better you'd have to define what better means. – Intussuscept

@TedKleinBergman okay, you're right :D Then I just want to know the difference. – Piccalilli

Answer 1

In the Rust ecosystem, these are called channels. There are three official channels:

• Stable: this is the default one, that most people should use normally. As its name implies, stability is the main feature.
• Beta: this is a preview for the next version of Rust. The main idea is that you add it to your CI, testings or whatever, so you can discover any issue that new Rust developments may cause to your code, and report them back to the Rust team. You can also use it to preview future improvements to the language or the standard library, of course, but it will not let you use unstable features.
• Nightly: this is build every day (or night), so it shows the bleeding edge version of the Rust code base. As such it may show random bugs or changes in behavior from one version to the next. But it allows you to use unstable features. Some people avoid the random bug issue by pinning their project to a particular known-good nightly version, by specifying the date.

To sum up: use stable to do normal work; use nightly to experiment with unstable features; use beta to test the next Rust version and get ahead of possible future problems.

Selmner

It is worth saying that the nightly channel is pretty stable and some teams use it in production (after pinning of course). – Intention

@ChayimFriedman: I agree and I think it is worth being more specific. The nightly releases are still fully tested by the Rust repository CI, on all Tier 1 platforms. The stability varies with the maturity of the features: stable features are nigh as stable as on the stable channel, just stabilized features are as stable as on the beta channel (no expected API break, well-tested), and the more "work-in-progress" features are the least stable with potential API break and spotty test coverage. – Marshland