Rust image missing rustdoc despite documentation claiming that it is included

[ltagliaferri]

Which image/versions are related to this issue/feature request?

Rust

Issue/Feature description

I'm copying this over from the edu repo, as reported by @emilal

Describe the bug
When attempting to build something that uses rustdoc in its build process, the image build process fails.

E.g. if building an image that uses the crate rav1e, which depends on built, the build process will fail with

Error: failed to run custom build command for rav1e v0.7.1

Caused by:
process didn't exit successfully: /work/target/debug/build/rav1e-630d2ba1731d92a3/build-script->build (exit status: 101)
--- stderr
thread 'main' panicked at /home/nonroot/.cargo/registry/src/> index.crates.io-6f17d22bba15001f/rav1e-0.7.1/build.rs:250:29:
Failed to acquire build-time information: Os { code: 2, kind: NotFound, message: "No such file or directory" }
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
Error: building at STEP "RUN cargo build": while running runtime: exit status 101

(The built crate may be updated to handle missing rustdoc better: lukaslueg/built#64)

The rust image documentation (cgr.dev/chainguard/rust, https://edu.chainguard.dev/chainguard/chainguard-images/reference/rust) claims that rustdoc is installed; while the image itself appears to only include the manpages for rustdoc.

To Reproduce

Steps to reproduce the behavior:

1. cargo new broken
2. Add the following to Cargo.toml. (The default-features=false is to not get hit by another unrelated build error about missing nasm; which is irrelevant for this case.)

[dependencies.rav1e]
version = "0.7.1"
default-features = false

3. Create a Dockerfile like

FROM cgr.dev/chainguard/rust:latest
WORKDIR /work
COPY Cargo.toml .
COPY src/ src/
RUN cargo build

4. Build with e.g. podman build -t broken . or docker buildx build -t broken .
5. See error as quoted above.

The same error appears with latest-dev.

Expected behavior
I expect the image to be built successfully, or that the documentation states plainly that rustdoc is not included. Though as far as I can tell, not having rustdoc available is unexpected for the rust community.

The edu repository also doesn't immediately come off as the best place to submit bug reports about image contents, but it is the most obvious "send feedback" system.

Desktop (please complete the following information):

• OS: Any linux
• Browser: irrelevant

For completion's sake, though I don't seem to be impacted by it, rustlldb is also not present in the image, and not even with manpages.