1804530 - `wgpu` imports broken because `cargo vendor` can't handle workspace inheritance

Status: NEW

(Core :: Graphics: WebGPU, task, P1)

Description

[Jim Blandy :jimb]

This cargo vendor bug is blocking our wgpu imports: https://github.com/rust-lang/cargo/issues/11192

Using mach vendor rust to bring in git dependencies, like those used in gfx/wgpu_bindings/Cargo.toml, produces broken crate sources in third_party/rust.

wgpu uses Cargo workspace inheritance to avoid reiterating the same values over and over in every crate's Cargo.toml file, but cargo vendor (used by mach vendor rust) splits workspaces into individual crates. For crates published on crates.io, cargo vendor takes advantage of the fact that cargo publish already handles rewriting the Cargo.toml files to be independent of their workspace, but for git dependencies - picking a specific commit out of a git repository - cargo vendor seems to just copy the crate's subtree out of the workspace without fixing up its Cargo.toml file. This gives a crate that doesn't build, because its Cargo.toml file has stuff like this:

[package]
name = "wgpu-core"
version.workspace = true
authors.workspace = true
edition.workspace = true
description = "WebGPU core logic on wgpu-hal"
homepage.workspace = true
repository.workspace = true
keywords.workspace = true
...

which doesn't fly.

Comment 1

[Jim Blandy :jimb]

From the https://github.com/rust-lang/cargo/issues/11192#issuecomment-1272364357:

In the meanwhile, we are seeking help for polishing the error message. Something explicitly tells user the cause is great, such like "vendoring a git dependency with inherited fields from a workspace is not supported yet".

Comment 2

[Jim Blandy :jimb]

Landed workaround upstream: https://github.com/gfx-rs/wgpu/pull/3295

Comment 3

[Jim Blandy :jimb]

Since there's a workaround landed upstream, kicking this out of webgpu-in-nightly's blockers.

I don't think it needs to block anything else.

Comment 4

[Jim Blandy :jimb]

rust-lang/cargo#11192 has landed, so this may be fixed.

Comment 5

[Jim Blandy :jimb]

Once the fix is available in a stable cargo, we can close this Bugzilla bug.

Comment 6

[Jim Blandy :jimb]

The fix for this bug shipped in Cargo 1.68. Since Firefox 115's MSRV is still 1.66, I think we should leave this open.

Comment 7

[Jim Blandy :jimb]

Firefox's MSRV is still 1.66.

Comment 8

[Erich Gubler [:ErichDonGubler]]

Upstream issue: https://github.com/gfx-rs/wgpu/issues/3407