What causes "tap repository tree was truncated" in jdx/mise?

Retry the operation — truncation can occasionally vary, though for genuinely oversized trees it will recur.

tap repository tree was truncated

Error message

tap repository tree was truncated

What it means

When inspecting a Homebrew tap via the GitHub API (GET /git/trees/{commit}), the response can carry truncated=true, meaning GitHub omitted entries because the tree is too large. The library refuses to continue because formula discovery would silently miss directories/files, so it bails with this error rather than return incomplete results.

Source

Thrown at src/system/packages/brew/tap.rs:261

    let mut parts = rest.split('/');
    match (parts.next(), parts.next(), parts.next()) {
        (Some(repo_owner), Some(repo), None) if !repo_owner.is_empty() && !repo.is_empty() => {
            Ok((repo_owner, repo.to_string()))
        }
        _ => bail!("invalid GitHub tap URL '{url}'"),
    }
}

async fn fetch_formula_source(tap_source: &TapSource, name: &str) -> Result<(String, String)> {
    let root_tree: GithubTree = HTTP_FETCH
        .json_cached(format!(
            "{}/git/trees/{}",
            tap_source.api_base, tap_source.commit
        ))
        .await
        .wrap_err("failed to inspect tap formula directories")?;
    if root_tree.truncated {
        bail!("tap repository tree was truncated");
    }

    let (directory, formula_tree) =
        if let Some((directory, sha)) = active_formula_directory(&root_tree) {
            let tree: GithubTree = HTTP_FETCH
                .json_cached(format!(
                    "{}/git/trees/{sha}?recursive=1",
                    tap_source.api_base
                ))
                .await
                .wrap_err_with(|| format!("failed to inspect tap {directory} directory"))?;
            if tree.truncated {
                bail!("tap {directory} directory tree was truncated");
            }
            (directory, tree)
        } else {
            ("", root_tree)
        };

View on GitHub (pinned to afd2eddd3a)

Solutions

Retry the operation — truncation can occasionally vary, though for genuinely oversized trees it will recur.
Use a full git clone of the tap instead of the GitHub trees API, then read the formula locally.
Narrow the query to a specific subdirectory or path so the returned tree stays under GitHub's limits.
Pin to a specific commit whose tree is smaller, or split the tap into smaller taps.

Example fix

// before: relying on trees API for a huge tap
let tree = github_tree(api_base, commit).await?;
// after: fall back to a local clone when the API tree is truncated
let tree = match github_tree(api_base, commit).await {
    Ok(t) if !t.truncated => t,
    _ => clone_and_read_tap_locally(tap_url, commit).await?,
};

Defensive patterns

Strategy: retry

Validate before calling

// No client-side pre-check possible; GitHub sets truncated itself.
// Detect it after the call and fall back:
let tree: GithubTree = resp.json().await?;
if tree.truncated { /* fall back to git clone */ }

Type guard

fn is_complete_tree(t: &GithubTree) -> bool { !t.truncated }

Try / catch

match fetch_formula_source(tap, name).await {
    Err(e) if e.to_string().contains("truncated") => clone_tap_and_read_locally(tap, name).await,
    other => other,
}

Prevention

Prefer a local git clone for very large taps instead of the trees API
Keep taps small; avoid monorepo-scale tap repositories
Cache successful tree responses and only re-query on commit change

When it happens

Trigger: fetch_formula_source calls the GitHub trees API for the tap's commit and the returned root tree has truncated=true — i.e. the tap repository tree exceeds GitHub's tree API limits (very large repos, taps with thousands of entries or huge non-formula directories).

Common situations: Querying very large or monorepo-style taps (e.g. homebrew/cask or an enormous personal tap) whose root tree exceeds GitHub's size cap; network-level API usage without any narrowing ref; GitHub truncating trees for repos with tens of thousands of objects.

Understand the failure class

Background: "API error: {status}" and "HTTP 401/403/404/429/5xx" errors: non-2xx HTTP responses explained — this error's family across 27 libraries.

Related errors

AI-assisted analysis of jdx/mise@afd2eddd3a (2026-09-09). Data as JSON: /api/errors/922aaeed3549d615. Report an issue: GitHub.