chore: Rust format and testing in CI

[aclauer]

Problem

Need to run Rust formatting checks and tests in CI

Closes DIM-938

Solution

Added auto discovery job to find all Rust workspaces in the repository based on Cargo.lock. Then run cargo fmt, cargo clippy, cargo test in all work spaces in parallel.

How to Test

Run in CI, result of all three commands matches local results. All workspaces are automatically detected without any hardcoded paths.

Contributor License Agreement

• I have read and approved the CLA.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

[greptile-apps]

Greptile Summary

This PR introduces a rust CI job that auto-discovers all Cargo workspaces via find Cargo.lock, then runs cargo fmt, cargo clippy, and cargo test across every discovered workspace. The job is added as a required gate in ci-complete.

• Workspace discovery uses find with GNU-specific -printf '%h\ ', which is correct on ubuntu-latest and the output is safely passed as a multiline heredoc to GITHUB_OUTPUT.
• Cargo commands all scope to the full workspace (--workspace, --all-targets, --all-features, --locked); fmt, clippy, and tests are guarded consistently.
• Sequential loops process each discovered workspace one at a time in a single runner, which diverges from the PR description's claim of parallel execution.

Confidence Score: 5/5

Safe to merge — the workflow correctly discovers workspaces, runs all three cargo checks with appropriate flags, and gates ci-complete on the new job.

The cargo commands are well-formed, workspace flags are consistent across all three steps, and the heredoc output pattern is correctly used. The only gap is that the workspace loops run sequentially rather than in parallel, but this is a performance concern, not a correctness one.

No files require special attention; the single changed file is straightforward CI configuration.

Important Files Changed

Filename	Overview
.github/workflows/ci.yml	Adds a rust job that auto-discovers Cargo workspaces via find, then sequentially runs cargo fmt, cargo clippy, and cargo test in each; job is wired into ci-complete as a required gate

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Push / PR event] --> B[rust job]
    B --> C[Checkout]
    C --> D[Find Cargo workspace roots\nfind Cargo.lock → crates output]
    D --> E[Install Rust toolchain\nrustfmt + clippy]
    E --> F[Cache cargo build\nSwatinem/rust-cache]
    F --> G[cargo fmt loop\nfor each workspace sequentially]
    G --> H[cargo clippy loop\nfor each workspace sequentially]
    H --> I[cargo test loop\nfor each workspace sequentially]
    I --> J[ci-complete gate\nalls-green check]
    J -->|pass| K[Branch protection satisfied]
    J -->|fail| L[PR blocked]

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_{Reviews (4): Last reviewed commit: "Remove crate matrix and discovery job" | Re-trigger Greptile}

[leshy]

@Dreamsorcerer can you review?

[Dreamsorcerer]

One blocking detail here I think. I don't think we should be using a matrix here, atleast from what I see of the current run.

Currently, this results in 3 separate jobs, requiring 3 workers. Each job only takes ~20s with about 50% of that time doing the setup/teardown of the job.

So currently this is basically 3 x 20s, instead of 1 x 40s. The difference today is neglible, but if we start adding in more crates over time, then this will lead to worker starvation and delay the other (slower) test jobs.

[leshy]

oops I approved, but disabled auto-merge, letting you guys decide, just ping me when you need approval

[aclauer]

That's a good point, I'll change that

[aclauer]

should be fixed now, also removed the separate discover job