BoundaryML/baml · error

project name cannot be empty

Error message

project name cannot be empty

What it means

validate_project_name enforces Cargo-style rules before scaffolding: the name must be non-empty and consist only of ASCII alphanumerics, `-`, `_`, `.`. An empty name is rejected first. The whitelist exists because the name is embedded verbatim into a quoted TOML string in baml.toml, so stray characters would corrupt the manifest.

Source

Thrown at baml_language/crates/baml_cli/src/init_command.rs:170

/// Derive a project name from the canonical path's basename. Returns
/// `None` if the path has no usable basename (e.g. `/`), letting the
/// caller fall back to a hard-coded default.
fn default_project_name(canonical: &Path) -> Option<String> {
    canonical
        .file_name()
        .and_then(|s| s.to_str())
        .filter(|s| !s.is_empty())
        .map(|s| s.to_string())
}

/// Cargo-style project-name rules: non-empty, ASCII alphanumeric plus
/// `-`, `_`, `.`. Whitelist beats blacklist here — `render_baml_toml`
/// drops the name straight into a `"..."` TOML string, so a stray `"`
/// (or any control char) in the name produces an unparseable manifest.
fn validate_project_name(name: &str) -> Result<()> {
    if name.is_empty() {
        anyhow::bail!("project name cannot be empty");
    }
    let bad: Vec<char> = name
        .chars()
        .filter(|c| !(c.is_ascii_alphanumeric() || matches!(c, '-' | '_' | '.')))
        .collect();
    if !bad.is_empty() {
        anyhow::bail!(
            "project name `{name}` contains invalid character(s) {bad:?}. \
             Use ASCII letters, digits, `-`, `_`, or `.`."
        );
    }
    Ok(())
}

fn render_baml_toml(name: &str) -> String {
    format!(
        r#"[package]
name = "{name}"

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Pass a non-empty name: `baml init myproj --name myproj`.
2. Omit `--name` and let scaffold derive the name from the path if supported.
3. Fix the calling script so the name variable defaults to the directory name instead of empty.

Example fix

// before
baml init ./svc --name "$NAME"   // NAME empty -> bail
// after
baml init ./svc --name "${NAME:-svc}"

# guard before `baml init --name "${NAME}"`
[ -n "$NAME" ] || { echo "project name cannot be empty"; exit 1; }

When it happens

Trigger: Run `baml init <path> --name ""` (or otherwise pass an empty name) so scaffold() calls validate_project_name with an empty string.

Common situations: Scripted init invocations where a name variable is unset/empty and substituted as `--name ""`.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• project name `{name}` contains invalid character(s) {bad:?}.
• unknown feedback field(s) {}; only "title" and "description"
• feedback field "{key}" must be a string
• feedback needs a title; pass --title "..." or a JSON payload
• feedback payload must be a JSON object like {"title": "..."}

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/3465ba7226aa7671. Report an issue: GitHub.