rustc (beta) compilation problem when using tarball

[semarie]

I have a problem for building rustc (beta) using tarball with vendored crates.

The build fail early with:

Building bootstrap
running: /usr/local/bin/cargo build --jobs=default --manifest-path /data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/Cargo.toml -Zroot-dir=/data/semarie/build-rust/build_dir/rustc-beta-src --frozen
error: duplicate key
  --> vendor/libffi-sys-4.0.0/Cargo.toml:46:1
   |
46 | default = ["std"]
   | ^^^^^^^
error: failed to get `cc` as a dependency of package `bootstrap v0.0.0 (/data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap)`

Caused by:
  failed to load source for dependency `cc`

Caused by:
  Unable to update registry `crates-io`

Caused by:
  failed to update replaced source registry `crates-io`
Traceback (most recent call last):
  File "/data/semarie/build-rust/build_dir/rustc-beta-src/x.py", line 53, in <module>
    bootstrap.main()
  File "/data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/bootstrap.py", line 1410, in main
    bootstrap(args)
  File "/data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/bootstrap.py", line 1362, in bootstrap
    build.build_bootstrap()
  File "/data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/bootstrap.py", line 1029, in build_bootstrap
    run(args, env=env, verbose=self.verbose, cwd=self.rust_root)
  File "/data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/bootstrap.py", line 237, in run
    raise RuntimeError(err)
RuntimeError: failed to run: /usr/local/bin/cargo build --jobs=default --manifest-path /data/semarie/build-rust/build_dir/rustc-beta-src/src/bootstrap/Cargo.toml -Zroot-dir=/data/semarie/build-rust/build_dir/rustc-beta-src --frozen

After checking vendor/libffi-sys-4.0.0/Cargo.toml, the problem seems the crate has two default keys defined:

[features]
default = ["system"]
check_only = []
complex = []
default = ["std"]
std = []
system = []

I am unsure about the origin of the problem as libffi-sys 4.0.0 seems fine in its repository

[semarie]

after checking vendor/libffi-sys-4.0.0/Cargo.toml.orig, the file is fine. so it seems to be a problem cargo "normalization" ?

anyway, the compilation using vendored crates is failing, and it could be a problem when beta will reach stable as downstream will use tarball and vendored crates.

[cuviper]

I don't see this -- both of these have only the one default line:

• 1.92.0-beta.1 https://static.rust-lang.org/dist/2025-10-28/rustc-beta-src.tar.xz
• 1.92.0-beta.2 https://static.rust-lang.org/dist/2025-11-01/rustc-beta-src.tar.xz

$ grep -C3 default vendor/libffi-sys-4.0.0/Cargo.toml
[features]
check_only = []
complex = []
default = ["std"]
std = []
system = []

Are you sure you don't have local patches or other modifications applied?

[semarie]

Thanks for the check.

I am using different url for the tarball (https://static.rust-lang.org/dist/rustc-beta-src.tar.gz) but I am seeing same as you if I look at rustc-beta-src/vendor/libffi-sys-4.0.0/Cargo.toml from the tarball. I will review my build script as such changes are unexpected.

Sorry for the noise