What causes "expected {} size-gate reports from run {run_id}, found {}" in BoundaryML/baml?

Re-run the CI workflow so all required reports are uploaded, then retry the fetch

expected {} size-gate reports from run {run_id}, found {}

Error message

expected {} size-gate reports from run {run_id}, found {}

What it means

The size-gate tool downloads CI artifact reports for a workflow run and expects at least one JSON report per required artifact. If `find_json_reports` finds fewer JSON files than `REQUIRED_ARTIFACTS` entries, it bails with this message. It means the run did not produce/upload all expected size reports, so the gate cannot be evaluated.

Source

Thrown at baml_language/crates/tools_size_gate/src/fetch.rs:140

        .with_context(|| format!("failed to create {}", download_dir.display()))?;
    gh(&[
        "run",
        "download",
        &run_id,
        "--repo",
        &repo,
        // `size-gate-*` matches the per-platform reports and NOT the
        // `cargo-timings-size-gate-*` artifacts (different prefix).
        "--pattern",
        "size-gate-*",
        "--dir",
        &download_dir.to_string_lossy(),
    ])
    .with_context(|| format!("failed to download reports from run {run_id}"))?;

    let files = find_json_reports(download_dir)?;
    if files.len() < REQUIRED_ARTIFACTS.len() {
        bail!(
            "expected {} size-gate reports from run {run_id}, found {}",
            REQUIRED_ARTIFACTS.len(),
            files.len()
        );
    }

    Ok(Fetched {
        files,
        run_id,
        head_sha: chosen.head_sha.clone(),
    })
}

/// True if run `run_id` has every artifact in `REQUIRED_ARTIFACTS`.
fn run_has_all_reports(repo: &str, run_id: u64) -> Result<bool> {
    let names = gh(&[
        "api",
        "--paginate",

View on GitHub (pinned to bd85ce9dee)

Solutions

Re-run the CI workflow so all required reports are uploaded, then retry the fetch
Check the run on GitHub (gh run view <run_id>) to see which jobs/artifacts are missing
Download the report JSONs manually and pass them as explicit file paths instead of --branch
Verify REQUIRED_ARTIFACTS matches what the workflow actually uploads

Example fix

// before: gate fails because old run lacks new artifact
size-gate check --branch main
// after: use an explicit run that has all artifacts, or supply files
size-gate check --branch main --run-id 1234567
// or
size-gate check reports/*.json

Defensive patterns

Strategy: validation

Validate before calling

let artifacts = json_run_artifacts(run_id)?;
let missing: Vec<_> = REQUIRED_ARTIFACTS.iter().filter(|a| !artifacts.contains(a)).collect();
if !missing.is_empty() { eprintln!("run {run_id} missing artifacts: {missing:?}"); std::process::exit(1); }

Prevention

Before gating, assert the CI run's status is completed and successful
Upload all reports as a single grouped artifact so they succeed/fail together
Keep REQUIRED_ARTIFACTS in sync with the workflow's upload steps
Prefer passing explicit report files over --branch in flaky CI contexts

When it happens

Trigger: Running size-gate with --branch (fetch_branch_reports) where the resolved GitHub Actions run lacks some required artifacts: the run is still in progress, some jobs failed before uploading reports, or artifacts were pruned/deleted.

Common situations: Fetching reports for a branch whose CI run partially failed; a workflow that uploads artifacts only on success; retention expiry removing artifacts; adding a new artifact to REQUIRED_ARTIFACTS while older runs did not produce it.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/ff4e067823de6f8e. Report an issue: GitHub.