devenv: Install pinned nightly Rust toolchain via rustup by cgwalters · Pull Request #122 · bootc-dev/infra

cgwalters · 2026-03-03T12:28:13Z

I want to start using cargo fuzz; it requires a nightly toolchain per https://rust-fuzz.github.io/book/cargo-fuzz/setup.html

Pin to a version that gets renovate-bumped.
(In the future I'd like to CI gate that our devenv works on
some representative projects)

Renovate is configured to track new nightlies via a custom datasource that reads the official Rust release manifest (manifests.txt), using the rust-release-channel versioning scheme. This is the same data source the upcoming native rust-version datasource will use (renovatebot/renovate#39529); once that merges this custom config can be replaced with zero-config native support.

Tested: podman run <image> cargo +nightly --version succeeds in the resulting c10s container image.

Assisted-by: OpenCode (Claude claude-opus-4-6)

I want to start using `cargo fuzz`; it requires a nightly toolchain per https://rust-fuzz.github.io/book/cargo-fuzz/setup.html Pin to a version that gets renovate-bumped. (In the future I'd like to CI gate that our devenv works on some representative projects) Renovate is configured to track new nightlies via a custom datasource that reads the official Rust release manifest (manifests.txt), using the rust-release-channel versioning scheme. This is the same data source the upcoming native rust-version datasource will use (renovatebot/renovate#39529); once that merges this custom config can be replaced with zero-config native support. Tested: `podman run <image> cargo +nightly --version` succeeds in the resulting c10s container image. Assisted-by: OpenCode (Claude claude-opus-4-6) Signed-off-by: Colin Walters <walters@verbum.org>

gemini-code-assist · 2026-03-03T12:28:31Z

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the development environment by introducing support for a pinned Rust nightly toolchain. This change is crucial for utilizing features that require a nightly build, such as cargo fuzz. It also integrates Renovate to ensure that the nightly toolchain version is automatically kept up-to-date, improving maintainability and reducing manual intervention for dependency management.

Highlights

Pinned Rust Nightly Toolchain: Implemented the installation of a specific, pinned Rust nightly toolchain in the development environment, enabling access to features like cargo fuzz.
Renovate Integration for Nightly Updates: Configured Renovate to automatically track and bump the pinned Rust nightly toolchain version by introducing a custom datasource and manager rules.
Containerfile Updates: Modified Containerfile.c10s and Containerfile.debian to accept a rust_nightly argument, allowing for dynamic installation of the specified nightly toolchain.

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Changelog

devenv/Containerfile.c10s
- Added an ARG for rust_nightly with a default pinned date.
- Modified the install-rust.sh command to use the rust_nightly argument.
devenv/Containerfile.debian
- Added an ARG for rust_nightly with a default pinned date.
- Modified the install-rust.sh command to use the rust_nightly argument.
devenv/install-rust.sh
- Implemented conditional logic to install a specified Rust nightly toolchain using rustup.
- Created a symlink from the dated nightly toolchain to a generic nightly toolchain for easier access.
renovate-shared-config.json
- Defined a new custom datasource rust-nightly to track Rust nightly releases from the official manifest.
- Expanded customManagers regex for managerFilePatterns to match Containerfile and Dockerfile with various extensions.
- Updated customManagers match strings to support versioning and a broader range of datasource names.
- Added a versioning rule for custom.rust-nightly to use rust-release-channel.

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Code Review

This pull request introduces the installation of a pinned nightly Rust toolchain, managed by Renovate, by updating Containerfiles, modifying the Rust installation script, and configuring Renovate. No security vulnerabilities were found. However, a critical issue was identified: the default nightly version is set to a future date, which will cause container builds to fail. It is recommended to use a valid, existing nightly version. Additionally, suggestions have been provided to improve the robustness of the installation script.

gemini-code-assist · 2026-03-03T12:30:05Z

devenv/Containerfile.c10s


 FROM base as rust
+# renovate: datasource=custom.rust-nightly depName=rust-nightly versioning=rust-release-channel
+ARG rust_nightly=nightly-2026-03-02


The date 2026-03-02 is in the future. The rustup toolchain install command will fail because this nightly toolchain does not exist, which will break the container build. Please use a valid, existing nightly version to ensure the build works correctly before Renovate's first update.

ARG rust_nightly=nightly-2024-03-02

gemini-code-assist · 2026-03-03T12:30:05Z

devenv/Containerfile.debian


 FROM base as rust
+# renovate: datasource=custom.rust-nightly depName=rust-nightly versioning=rust-release-channel
+ARG rust_nightly=nightly-2026-03-02


The date 2026-03-02 is in the future. The rustup toolchain install command will fail because this nightly toolchain does not exist, which will break the container build. Please use a valid, existing nightly version to ensure the build works correctly before Renovate's first update.

ARG rust_nightly=nightly-2024-03-02

gemini-code-assist · 2026-03-03T12:30:05Z

devenv/install-rust.sh

+  /usr/local/cargo/bin/rustup toolchain install "${rust_nightly}" --profile minimal
+  # Symlink the dated nightly as "nightly" so `cargo +nightly` works without
+  # requiring write access to RUSTUP_HOME for channel updates.
+  host=$(/usr/local/cargo/bin/rustc -vV | awk '/^host:/{print $2}')


Parsing the output of rustc -vV is brittle as its format is not guaranteed to be stable. A more robust way to get the host triple is to use rustc --print target-triple, which is designed for programmatic use.

Suggested change

host=$(/usr/local/cargo/bin/rustc -vV | awk '/^host:/{print $2}')

host=$(/usr/local/cargo/bin/rustc --print target-triple)

gemini-code-assist · 2026-03-03T12:30:06Z

devenv/install-rust.sh

+  # Symlink the dated nightly as "nightly" so `cargo +nightly` works without
+  # requiring write access to RUSTUP_HOME for channel updates.
+  host=$(/usr/local/cargo/bin/rustc -vV | awk '/^host:/{print $2}')
+  ln -s "${rust_nightly}-${host}" "$RUSTUP_HOME/toolchains/nightly-${host}"


It's good practice to use ln -sf to create symbolic links in scripts. The -f (force) option will overwrite the destination file if it already exists. This makes the script more robust and idempotent, preventing errors if it's run multiple times or if a nightly symlink already exists for some reason.

Suggested change

ln -s "${rust_nightly}-${host}" "$RUSTUP_HOME/toolchains/nightly-${host}"

ln -sf "${rust_nightly}-${host}" "$RUSTUP_HOME/toolchains/nightly-${host}"

henrywang · 2026-03-04T01:36:08Z

renovate-shared-config.json

    {
      "customType": "regex",
-      "managerFilePatterns": ["(^|/)Containerfile$", "(^|/)Dockerfile$"],
+      "managerFilePatterns": ["(^|/)Containerfile(\\.[a-z0-9]+)?$", "(^|/)Dockerfile(\\.[a-z0-9]+)?$"],


There's a conflict. I think "managerFilePatterns": ["/(^|/)Containerfile(\\.[^/]*)?$/", "/(^|/)Dockerfile(\\.[^/]*)?$/"] is a better one.
It uses proper regex delimiters with /(^|/)...$/ and [^/]*.

gemini-code-assist bot reviewed Mar 3, 2026

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cgwalters requested a review from henrywang March 3, 2026 18:55

henrywang reviewed Mar 4, 2026

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henrywang approved these changes Mar 4, 2026

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devenv: Install pinned nightly Rust toolchain via rustup#122

devenv: Install pinned nightly Rust toolchain via rustup#122
cgwalters wants to merge 1 commit intobootc-dev:mainfrom
cgwalters:devenv-nightly

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	host=$(/usr/local/cargo/bin/rustc -vV \| awk '/^host:/{print $2}')
	host=$(/usr/local/cargo/bin/rustc --print target-triple)

	ln -s "${rust_nightly}-${host}" "$RUSTUP_HOME/toolchains/nightly-${host}"
	ln -sf "${rust_nightly}-${host}" "$RUSTUP_HOME/toolchains/nightly-${host}"

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