nautechsystems/nautilus_trader · error

Gamma filter ' ' must be true or false, was

Error message

Gamma {scope} filter '{key}' must be true or false, was '{value}'

What it means

Certain Gamma filters (e.g. boolean flags like include_tag-style options) must be the string 'true' or 'false' (case-insensitive). parse_gamma_filter_bool raises this error for any other value, since the Gamma API expects strict booleans.

Solutions

1. Change the value to exactly 'true' or 'false' (any case is accepted)
2. Normalize the input: parse it as a bool in the caller (parse::<bool> or a config bool) and stringify as 'true'/'false'
3. If the source uses 1/0 or yes/no, map those explicitly before passing

Example fix

// before
filters.insert("active".into(), "1".into());
// after
filters.insert("active".into(), "true".into());

fn as_gamma_bool(v: &str) -> Option<&str> {
    match v.to_ascii_lowercase().as_str() {
        "true" => Some("true"),
        "false" => Some("false"),
        _ => None,
    }
}

fn is_gamma_bool(v: &str) -> bool {
    v.eq_ignore_ascii_case("true") || v.eq_ignore_ascii_case("false")
}

When it happens

Trigger: Supplying values like 'yes', '1', 'TRUE ', 'on', or an empty string for a boolean filter key in a markets or events filter map.

Common situations: Reading filter values from env vars or config files where '1'/'0' or 'yes'/'no' conventions are used; user-supplied query strings; YAML/TOML booleans stringified inconsistently.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Gamma filter ' ' cannot be empty
• Gamma filter ' ' must contain non-empty comma-separated…
• invalid Derive `expired` filter
• negative quantity
• negative tick count for Quantity

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/ef73917ebc73b952. Report an issue: GitHub.

Appendix: source

Thrown at crates/adapters/polymarket/src/providers.rs:975

    set_decimal!(volume_min);
    set_decimal!(volume_max);
    set_u32!(event_week);
    set_u32!(limit);
    set_u32!(offset);
    set_u32!(max_events);
    set_u64!(parent_event_id);

    params.validate_keyset().map_err(anyhow::Error::msg)?;
    Ok(params)
}

fn parse_gamma_filter_bool(scope: &str, key: &str, value: &str) -> anyhow::Result<bool> {
    if value.eq_ignore_ascii_case("true") {
        Ok(true)
    } else if value.eq_ignore_ascii_case("false") {
        Ok(false)
    } else {
        anyhow::bail!("Gamma {scope} filter '{key}' must be true or false, was '{value}'")
    }
}

fn parse_gamma_filter_u32(scope: &str, key: &str, value: &str) -> anyhow::Result<u32> {
    value.parse::<u32>().map_err(|e| {
        anyhow::anyhow!("Gamma {scope} filter '{key}' must be an unsigned integer: {e}")
    })
}

fn parse_gamma_filter_u64(scope: &str, key: &str, value: &str) -> anyhow::Result<u64> {
    value.parse::<u64>().map_err(|e| {
        anyhow::anyhow!("Gamma {scope} filter '{key}' must be an unsigned integer: {e}")
    })
}

fn parse_gamma_filter_decimal(scope: &str, key: &str, value: &str) -> anyhow::Result<Decimal> {
    parse_decimal_exact(value)
        .map_err(|e| anyhow::anyhow!("Gamma {scope} filter '{key}' must be a decimal number: {e}"))

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