Closed Bug 1366542 Opened 3 years ago Closed 3 years ago

Bump requirement of Rust version to what we use on builders


(Firefox Build System :: General, enhancement)

Not set


(firefox55 fixed)

Tracking Status
firefox55 --- fixed


(Reporter: xidorn, Assigned: xidorn)



(1 file)

We are continuously introducing code which may break old version of Rust, and we don't really care about old versions as far as I'm aware. But it could cause annoyance when people try to build with old version while mach doesn't upgrade Rust for them.

Some code I checked in several days ago start requiring 1.17.0, while there are people still using older versions and hit build failure.
I think we really should bump the check every time we bump the version CI uses.

I've seen several people got confused when they checkout mozilla-central and find it doesn't build locally...
Corrolary: we shouldn't bump the version CI uses unless some new feature is needed.
That works as well. Anyway, having CI use different version than what build system requires is not helpful.
Given the rate of churn in Rust, my opinion is that we should require the version of Rust that is the lowest of what we run in CI. This means we can deploy a one-off build testing an old version of Rust if we wish to keep supporting it. For capacity reasons, we'd want to limit that to a build variation - without tests. I'm not sure if that is valuable without tests. So this may revert to "require whatever CI uses." I also agree with glandium that we shouldn't bump to a new version until there is a compelling reason. In reality, the bar for "compelling" is probably quite low, as I consider developer ergonomics a very compelling reason!
Comment on attachment 8869791 [details]
Bug 1366542 - Bump required version of Rust to 1.17.0.
Attachment #8869791 - Flags: review?(mshal) → review+
Pushed by
Bump required version of Rust to 1.17.0. r=mshal
Closed: 3 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla55
Assignee: nobody → xidorn+moz
Product: Core → Firefox Build System
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