Support updating Bazelmod lock file when updating Cargo.toml

[tacascer]

Tell us more.

When Renovate updates a Cargo.toml file in a Bazel repo, it doesn't update the MODULE.lock.

This leads to errors like

(22:02:09) ERROR: Analysis of target '//nicknamer/server/bin:bin' failed; build aborted: MODULE.bazel.lock is no longer up-to-date because an input to the extension '@@rules_rust+//crate_universe:extensions.bzl%crate' changed: file info or contents of @@//Cargo.lock changed. Please run `bazel mod deps --lockfile_mode=update` to update your lockfile.

Suggestion

Renovate should update the Bazelmod lock file when it's updating Rust dependencies in Cargo.toml.

[tacascer]

I have a reproduction here:

https://github.com/tacascer/renovate-42046

[gzm0]

I have a similar request for:

• The pip-compile manager (for extensions in rules_python)
• pnpm-lock.yaml (for extensions in aspect_rules_js and apsect_rules_ts and some custom extensions we wrote).
• .nvmrc (for extensions in rules_node)

We currently work around this by having our custom post-upgrade task (of course you need to configure this in allowCommands as well) and configuring it as necessary via packageRules.

{
  commands: ["find . -name MODULE.bazel.lock -type f -print -execdir bazelisk mod deps --lockfile_mode=update \;"], // note: unverified, we indirect via a shell script.
  executionMode: "branch",
  installTools: { bazelisk: {} }
}

My gut feeling is that Renovate cannot possibly model all bazel module extensions. A general-purpose "trigger bzlmod lockfile update after this type of package update" mechanism would probably be more appropriate.

At this stage, I do not know how such a mechanism would look like. Open questions from the top of my head:

• How does bzlmod lockfile discovery look like? Is just updating all MODULE.bazel.lock files good enough?
• How would the config surface look like?
• How would the internal structure look like?