Sparse Registry Fails with Unsupported Protocol on nightly-2022-10-13

[robertwayne]

Problem

Trying to download crates from crates.io with the sparse registry feature enabled results in a failure

> rob@pop-os:/mnt/Primary/projects/sparse-error-test$ cargo +nightly -Z sparse-registry check

Updating crates.io index
error: failed to get `tokio` as a dependency of package `sparse-error-test v0.1.0 (/mnt/Primary/projects/sparse-error-test)`

Caused by:
  failed to query replaced source registry `crates-io`

Caused by:
  download of config.json failed

Caused by:
  failed to download from `sparse+https://index.crates.io/config.json`

Caused by:
  [1] Unsupported protocol (Protocol "sparse+https" not supported or disabled in libcurl)

> rob@pop-os:/mnt/Primary/projects/sparse-error-test$ cargo version
cargo 1.66.0-nightly (b332991a5 2022-10-13)

Running with cargo 1.66.0-nightly (b8f30cb23 2022-10-10) works fine.

Steps

1. Create a new project.
2. Add any crate to your Cargo.toml.
3. Run cargo +nightly -Z sparse-registry check.

Possible Solution(s)

No response

Notes

I see there were a bunch of commits between the nightly-2022-10-10 and nightly-2022-10-13 release relating to sparse registry, but I didn't see anything signalling a change from the prior behaviour or usage.

Version

cargo 1.66.0-nightly (b332991a5 2022-10-13)
release: 1.66.0-nightly
commit-hash: b332991a57c9d055f1864de1eed93e2178d49440
commit-date: 2022-10-13
host: x86_64-unknown-linux-gnu
libgit2: 1.5.0 (sys:0.15.0 vendored)
libcurl: 7.83.1-DEV (sys:0.4.55+curl-7.83.1 vendored ssl:OpenSSL/1.1.1q)
os: Pop!_OS 22.04 (jammy) [64-bit]

[Eh2406]

@arlosi want to take a look?

[folex]

Hi, thanks for the quick fix!

What's the best way to overcome this in CI? Clear cargo cache?

[arlosi]

Any of these methods will get you unblocked:

• Disable the sparse-registry flag
• Install an older nightly such as nightly-2022-10-10
• Wait for a newer nightly - should be available in a couple days.