What causes "URL cannot be empty." in xai-org/grok-build?

Re-run with the actual marketplace git URL or local path

URL cannot be empty.

Error message

URL cannot be empty.

What it means

`grok plugin marketplace add` requires a non-empty URL or path. The input is trimmed and, if empty, the command bails with 'URL cannot be empty.' before any classification or network work.

Source

Thrown at crates/codegen/xai-grok-pager/src/plugin_cmd.rs:854

                SourceKind::Git { url, .. } => url.clone(),
                SourceKind::Local { path } => path.display().to_string(),
            };
            println!("  {}: {id}", s.name);
        }
    }
    Ok(())
}

fn marketplace_add(
    sources: &[xai_grok_plugin_marketplace::MarketplaceSource],
    url: &str,
    force: bool,
) -> Result<()> {
    use xai_grok_shell::plugin::MarketplaceAddInput;

    let url = url.trim();
    if url.is_empty() {
        bail!("URL cannot be empty.");
    }

    let cwd = std::env::current_dir().unwrap_or_default();
    let input = plugin::classify_marketplace_add_input(url, &cwd);

    // Fail fast on missing local paths: otherwise a path input is stored as a git URL and only errors after network clone attempts
    if let MarketplaceAddInput::LocalPath(path) = &input
        && !path.is_dir()
    {
        bail!(
            "Local marketplace path not found (or is not a directory): {}",
            path.display()
        );
    }

    let identity = match &input {
        MarketplaceAddInput::GitUrl(u) => u.clone(),
        MarketplaceAddInput::LocalPath(p) => p.display().to_string(),

View on GitHub (pinned to bc7f02eddd)

Solutions

Re-run with the actual marketplace git URL or local path
Check the env var is set: `echo $MARKETPLACE_URL`
Quote the argument in scripts: `grok plugin marketplace add "$URL"`

Example fix

// before
grok plugin marketplace add $MARKETPLACE_URL   # unset → empty
// after
grok plugin marketplace add "https://github.com/org/marketplace.git"

Defensive patterns

Strategy: validation

Validate before calling

fn ensure_non_empty(input: &str) -> Result<&str, String> {
    let t = input.trim();
    if t.is_empty() {
        return Err("URL cannot be empty".into());
    }
    Ok(t)
}

Type guard

fn is_non_empty(s: &str) -> bool {
    !s.trim().is_empty()
}

Try / catch

match marketplace_add(input, None, false, false) {
    Err(e) if e.to_string().contains("URL cannot be empty") => {
        eprintln!("Provide a marketplace URL or local path");
    }
    Ok(_) => {}
    Err(e) => return Err(e),
}

Prevention

Quote shell variables: "$MARKETPLACE_URL"
Default-check env vars in scripts before invoking the CLI
Use interactive prompts that reject empty input

When it happens

Trigger: Running `grok plugin marketplace add` with an empty string or whitespace-only argument (e.g. an unset shell variable expands to nothing).

Common situations: `$MARKETPLACE_URL` environment variable unset; script passing empty arg; copy-paste dropped the URL; quoting mistake producing an empty string.

Related errors

AI-assisted analysis of xai-org/grok-build@bc7f02eddd (2026-08-31). Data as JSON: /api/errors/4a9df57353f2bd63. Report an issue: GitHub.