swc-project/swc · warning · anyhow::Error

{message}; run `cargo codegen helpers` and commit the genera

Error message

{message}; run `cargo codegen helpers` and commit the generated helper artifacts

What it means

Guard error from tools/generate-code (run via cargo codegen helpers): it regenerates the inline helper artifacts and compares them byte-for-byte with the committed files; any difference means the checked-in helpers are stale relative to the generator/templates. The message names the first stale file and instructs the fix - regenerate and commit.

Source

Thrown at tools/generate-code/src/main.rs:174

        let committed_path = &committed_files[&path];
        let committed = fs::read(committed_path)
            .with_context(|| format!("failed to read generated artifact: {committed_path:?}"))?;
        let generated = fs::read(&generated_path)
            .with_context(|| format!("failed to read generated artifact: {generated_path:?}"))?;

        if committed != generated {
            return Err(stale_helper_artifacts(format_args!(
                "generated helper artifact `{}` is stale",
                path.display()
            )));
        }
    }

    Ok(())
}

fn stale_helper_artifacts(message: std::fmt::Arguments<'_>) -> anyhow::Error {
    anyhow!("{message}; run `cargo codegen helpers` and commit the generated helper artifacts")
}

fn collect_files(root: &Path) -> Result<BTreeMap<PathBuf, PathBuf>> {
    let mut files = BTreeMap::new();
    collect_files_inner(root, root, &mut files)?;
    Ok(files)
}

fn collect_files_inner(
    root: &Path,
    dir: &Path,
    files: &mut BTreeMap<PathBuf, PathBuf>,
) -> Result<()> {
    for entry in fs::read_dir(dir)
        .with_context(|| format!("failed to read generated artifact directory: {dir:?}"))?
    {
        let entry = entry?;
        let path = entry.path();

View on GitHub (pinned to d7d7434666)

Solutions

1. Run `cargo codegen helpers` at repo root
2. Commit the regenerated artifacts together with the change that made them stale
3. Never hand-edit generated helper files; change templates and regenerate instead
4. If CI still fails, check that rustfmt/cargo-codegen versions match the repo's pinned toolchain

Example fix

# before: CI reports stale helper artifact
$ git commit -m "update helper template"

# after
$ cargo codegen helpers
$ git add crates/swc_ecma_transforms/src/helpers
$ git commit -m "update helper template + regenerate helpers"

# Shell: verify artifacts are fresh before pushing
cargo codegen helpers
git diff --exit-code -- crates/swc_ecma_transforms \
  || echo 'stale helper artifacts: run cargo codegen helpers and commit'

When it happens

Trigger: A PR modifies helper templates, the generator, or formatting but does not run `cargo codegen helpers`; or a contributor edits a generated helper file by hand; or codegen output changes across Rust/toolchain versions.

Common situations: CI codegen-consistency checks failing after touching crates/swc_ecma_transforms (or the generator in tools/generate-code); rebasing across a commit that changed generated output.

Related errors

• Failed to run cargo command
• module string names unimplemented
• module string names unimplemented
• module string names unimplemented
• module string names unimplemented

AI-assisted analysis of swc-project/swc@d7d7434666 (2026-08-16). Data as JSON: /api/errors/2a8d40cb522cb6a4. Report an issue: GitHub.