How to use nightly rust/cargo with renovate

[benniekiss]

How are you running Renovate?

Self-hosted Renovate CLI

Which platform you running Renovate on?

GitHub.com

Which version of Renovate are you using?

43.186.8

Please tell us more about your question or problem

I am trying to get renovate to use the nightly rust toolchain, as I require it for some unstable features. Mainly, for cargo-features = ["profile-rustflags"]. However, renovate fails to update cargo package deps because the stable version does not support the feature flag, so the Cargo.toml validation fails.

here are some failing CI builds:

https://github.com/benniekiss/minijinja-lua/actions/runs/26169173080

https://github.com/benniekiss/minijinja-lua/actions/runs/26163809522/job/76962333935

I have tried setting TOOL_VERSION, RUST_VERSION, and setting constraints.rust="nightly", but none of these work.

Is there currently a way to tell renovate to tell containerbase to use the nightly rust version, and if so, how?

In terms of the constraints.rust="nightly" failure, this is because the expected value is a valid semver version, as indicated in the docs and here. It seems there is a rust-release-channel versioning scheme that sounds like a better fit for this constraint, but I do not know how viable that implementation would be.

Logs (if relevant)

Logs

Replace this text with your logs, between the starting and ending triple backticks

[jamietanna]

Related to #38554 / #39529 / #39859 functionality, I wonder if yes rust-release-channel should be used instead.

If you use constraintsVersioning to override the versioning on your repo's config we can confirm if that does it for you - I'd be happy us making the change to migrate over to that by default if that does work

[benniekiss]

@jamietanna I was wondering if there was any progress towards nightly support, or if there were any significant blockers to implementing it.

Unfortunately, I don't believe there's currently any straightforward workaround for projects that require nightly cargo. I've even attempted to call install-tool rust nightly prior to running jobs, but renovate still fetches and tries to use the stable toolchain once it runs the cargo tasks.

[jamietanna]

Sorry - I did think about this one the other day, but didn't get a chance to look.

Taking more of a look now, we're currently seeing that:

• rust@nightly-2026-05-22 is suggested to be installed (which fails)
• this is because we provide a dated release from the rust-version Datasource
• this dated version is accepted by the rust-release-channel Versioning scheme
• but Containerbase doesn't know how to handle @nightly-2026-05-22, it only handles @nightly

[jamietanna]

OK, I've got this working (I've not yet pushed changes) - we need a fix in Containerbase, and in Renovate

[jamietanna]

OK, containerbase/base#6768 and #43543 should solve this 🤞🏼 Thanks for your patience!

[benniekiss]

this is wonderful. Thank you!