1481492 - Consider using rustup to find rustc and cargo paths

Status: RESOLVED DUPLICATE of bug 1547196

(Firefox Build System :: General, defect)

Description

[Blake Kaplan (:mrbkap) (inactive)]

I use rustup to manage my rust installation locally and tend to set its default to "nightly". Today I wanted to build off of mozilla-beta and the build died because of something added in a recent rust version (bug 1479540). rustup allows setting per-directory overrides of the current toolchain via `rustup override set ...`, but doing so in my beta directory has no effect. The reason is that at [1], we simply use ~/.cargo/bin which corresponds to rustup's default toolchain.

I've worked around this locally by adding

export RUSTC=$(rustup which rustc)
export CARGO=$(rustup which cargo)

to my mozconfig, but I think it might be nice if our build system detected if rustup was installed and, if so, asked it where to find rustc and cargo.

[1] https://searchfox.org/mozilla-central/rev/51268dcbdff0f6f4a5cff7986df0f616efc5bcfd/build/moz.configure/rust.configure#9,20-23

Comment 1

[(not currently active) Ted Mielczarek]

mrbkap: is your objdir not a child of your srcdir? If it was I assume that the rustup overrides would work as expected, since configure runs rustc from the objdir.

Comment 2

[Blake Kaplan (:mrbkap) (inactive)]

It isn't. My objdir is defined as:

mk_add_options MOZ_OBJDIR=$topsrcdir/../firefox