1424489 - MODERN_RUST_VERSION should use the rustc_min_version instead of duplicating the information

Status: RESOLVED WONTFIX

(Firefox Build System :: General, enhancement)

Description

[Sylvestre Ledru [:Sylvestre]]

As reported by bz here: https://bugzilla.mozilla.org/show_bug.cgi?id=1421097#c12

We had some mismatch of information about the minimal version of Rust.

To avoid this situation in the future, we should probably have https://dxr.mozilla.org/mozilla-central/source/python/mozboot/mozboot/base.py#153 using https://dxr.mozilla.org/mozilla-central/source/build/moz.configure/rust.configure#69
instead of duplicating the information.

Comment 1

[Nick Alexander :nalexander [he/him]]

I agree, but it's currently not easy to share information in this way, because the bootstrap code is supposed to be able to run without a source checkout.  That's dying for other reasons (|mach artifact install| isn't available without a source checkout) but until we give that flow up, these mismatches will require effort to work around.  The bootstrap android-packages.txt suffers from the same issue.

Comment 2

[Ralph Giles (:rillian)]

When we're bootstrapping, we're allowed to use network resources, so we could pull the file with the current version from the upstream repo if we don't have a current checkout.

Simon suggested recently that we derive both version from https://searchfox.org/mozilla-central/source/servo/rust-stable-version instead. This is a file shared between gecko and servo and would keep our respective minimum-version checks in sync. Implemented this, but didn't submit the patch because I was worried about the update mechanism. We'd need to update both that file and the base-toolchain build which verifies that minimum version for gecko in the same revision, or tests wouldn't pass. Stylo has a mechanism for this, but I don't think it's generally accessible.

After discussions today, I think we could add a transformation to the toolchain tasks which constructs the rust toolchain packaging tasks according to a template, and interpolate the single rust version into the base-toolchain build from wherever we store it when the test task is generated.

Comment 3

[Simon Sapin (:SimonSapin)]

https://github.com/servo/servo/pull/19395 has just landed, so rust-stable-version is replaced with geckolib-rust-toolchain. Although it should always be a stable version number, as far as Servo is concerned this file can technically contain any rustup.rs toolchain specification.

Comment 4

[Sylvestre Ledru [:Sylvestre]]

Closing as this isn't a big deal