Version incompatiblity between patch

[FaBrand]

Description
After upgrading the root module to rules_rust 0.70.0, bazel mod deps fails when the workspace contains an existing crate_universe lockfile generated before the upgrade and a downstream module still declaring rules_rust 0.68.1.

Expexted behaviour:
Tbh, not fully sure what would be a reasonable expectation.
It seems that the lockfile digest calculation lead to a breaking change from 0.68.1 -> 0.69.0

Reproduction steps
Standalone reproducer:

git clone https://github.com/FaBrand/rules_rust_incompatibility.git
cd rules_rust_incompatibility
bazel mod deps

The reproducer contains:

• root module using rules_rust 0.70.0
• local downstream module using rules_rust 0.68.1
• both modules using crate_universe with public crates
• checked-in crate-universe lockfiles generated before the root upgrade

Additional context
Observed error:

Error: Digests do not match: Current Digest("f723cdc33f33adbb226b472755c9d5e64631a013b3166296d488aa58fbafb8f7") != Expected Digest("e4409fddd63f29a438be3e7df8856a5dd9702bf47bca2ade256eaf0c06aea469")

The current `lockfile` is out of date for 'root_crates'. Please re-run bazel using `CARGO_BAZEL_REPIN=true` if this is expected and the lockfile should be updated.
ERROR: error evaluating module extension @@rules_rust+//crate_universe:extension.bzl%crate

Impact
This blocks a normal rules_rust upgrade path because the lockfile in version 0.70.0 yields a different digest than with 0.69.0 (or 0.68.1 as tested)

Bazel and rules_rust version
Bazel: 8.7.0

rules_rust:

• root module: 0.70.0
• downstream/local module: 0.68.1

[FaBrand]

I investigated a bit, it seems to me becuse Cargi/Rustc is part of the lockfile context

If a dependent Module has a older rules_rust version (e.g. 0.68.1) and the root workspace has a lockfile that was generated with a different Cargo/Rustc version it would break that lockfile in a Module Graph bazel mod deps