1730939 - Try servers with newer than MINIMUM_RUST_VERSION hides failures

Status: NEW

(Firefox Build System :: General, enhancement, P3)

Description

[Jon Bauman [:jbauman:]]

The other day I got bitten by using an "experimental" rust feature which is supported in rust 1.54, but not 1.51 (the current MINIMUM_RUST_VERSION).

What made this tricky is that the vast majority of our try machines use 1.54, so the mach try auto run was green, and only a much larger chooser run caught in in a few places.

I'm guessing this is an intentional choice to eke out the additional gains of running the latest and greatest despite the fact that it makes bugs less visible, but I wanted to make sure there isn't a bug to file here or something we could do better to help avoid this particular footgun. Personally, I've changed my local builds to always use MINIMUM_RUST_VERSION, but maybe there's something we can do to be of broader utility.

Comment 1

[Mitchell Hentges [:mhentges] 🦀]

Looks like the linux-base-toolchain build would have detected this issue, but it wasn't automatically scheduled by ./mach try auto. I've linked the related bug.