1516845 - Consider building and testing with Rust beta and nightly as tier-3 tasks on mozilla-central

Status: NEW

(Firefox Build System :: Task Configuration, task)

Description

[Xidorn Quan [:xidorn] UTC+11]

We may want to setup tier-3 tasks to build and test Firefox with Rust nightly and/or beta.

There are several reasons:
* This would help us tracking upstream changes closely, so that it would be less likely that we would need to handle regressions like bug 1451703 and bug 1456150 only when we are trying to bump the required Rust version.
* This would help contributors who may be more aggressive on Rust toolchain to have a smoother development experience, so that they are less likely to hit issues like bug 1516829.
* Gecko's Rust code base is a good real world testcase for Rust as well, so we testing against newer version of Rust would help Rust team as well.

Travis CI mentions in their Rust page that:
> The Rust team appreciates testing against the beta and nightly channels, even if you are only targeting stable.

We should probably do that as well.

This doesn't need to run very frequently, so a tier-3 task on m-c should be enough. WDYT?

Comment 1

[Tom Prince [:tomprince]]

This seems reasonable. If it is tier-3, it will probably only be looked at when people go out of their way to look at it, so it might make sense to just run it once a day (or even less often for beta maybe?)

Comment 2

[Xidorn Quan [:xidorn] UTC+11]

Yeah, maybe once a day would be enough. If we run it with nightly once a day, then yeah we can probably further reduce the frequency of running with beta.

Who would look at that at what frequency would be a question to be figured out.

Comment 3

[(not currently active) Ted Mielczarek]

We've talked about this many times, it would definitely help both us and the Rust team find issues earlier in our development cycles. The biggest problem is likely the reporting: making sure it's visible somehow and that issues get triaged appropriately so they get fixed instead of leaving the job broken all the time.

Comment 4

[Dustin J. Mitchell [:dustin] (he/him)]

Let's make sure these run on a single-tenancy EC2 instance, too.  The last failure involved OOM's, which can easily kill other tasks running at the same time on the same instance, and that's hard to debug.