nautechsystems/nautilus_trader · critical

invalid `PositionAdjustmentType` enum string value, was '{va

Error message

invalid `PositionAdjustmentType` enum string value, was '{value}'

What it means

position_adjustment_type_from_cstr converts a C string into a PositionAdjustmentType enum via FromStr. Unrecognized strings panic with this message; abort_on_panic converts the panic into a process abort at the FFI boundary. Only the exact variant strings produced by the enum's string conversions are accepted.

Source

Thrown at crates/model/src/ffi/enums.rs:789

}

/// Returns an enum from a C string.
///
/// # Safety
///
/// Assumes `ptr` is a valid C string pointer.
///
/// # Panics
///
/// Panics if the C string does not correspond to a valid `PositionAdjustmentType` variant.
#[unsafe(no_mangle)]
pub unsafe extern "C" fn position_adjustment_type_from_cstr(
    ptr: *const c_char,
) -> PositionAdjustmentType {
    abort_on_panic(|| {
        let value = unsafe { cstr_as_str(ptr) };
        PositionAdjustmentType::from_str(value).unwrap_or_else(|_| {
            panic!("invalid `PositionAdjustmentType` enum string value, was '{value}'")
        })
    })
}

#[unsafe(no_mangle)]
pub extern "C" fn price_type_to_cstr(value: PriceType) -> *const c_char {
    str_to_cstr(value.as_ref())
}

/// Returns an enum from a C string.
///
/// # Safety
///
/// Assumes `ptr` is a valid C string pointer.
///
/// # Panics
///
/// Panics if the C string does not correspond to a valid `PriceType` variant.

View on GitHub (pinned to 18893faf8b)

Solutions

1. Use the exact PositionAdjustmentType variant string; compare the '{value}' in the panic against the enum's FromStr definition.
2. Normalize config strings (trim, fix case) before calling the FFI function.
3. Whitelist-validate the string in the host language before the call.
4. Confirm the C string is NUL-terminated with no trailing garbage.
5. Rebuild the caller against the same crate version if the enum vocabulary changed.

Example fix

// before
position_adjustment_type_from_cstr("ADD"); // panics: not a variant

// after
position_adjustment_type_from_cstr("Add"); // exact PositionAdjustmentType variant string

const POSITION_ADJUSTMENT_TYPE_VARIANTS = new Set(["Add", "Subtract"]);
if (typeof adjType !== "string" || !POSITION_ADJUSTMENT_TYPE_VARIANTS.has(adjType)) {
  throw new Error(`unsupported PositionAdjustmentType: ${adjType}`);
}

function isPositionAdjustmentType(v) { return typeof v === 'string' && POSITION_ADJUSTMENT_TYPE_VARIANTS.has(v); }

Not applicable: the panic is converted to a process abort at the FFI boundary and cannot be caught. Validate the adjustment type string before calling position_adjustment_type_from_cstr.

When it happens

Trigger: Calling position_adjustment_type_from_cstr(ptr) with a string not accepted by PositionAdjustmentType::from_str, e.g. 'ADD', 'sub', 'RESET_POSITION', or an empty string. Only exact variant strings (as defined by the enum) parse.

Common situations: Configuring external position adjustments (e.g. corporate actions, manual reconciliations) over FFI with hand-written type names; case mismatches; whitespace from config parsing; version drift after variant renames.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• invalid `AggressorSide` enum string value, was '{value}'
• invalid `AssetClass` enum string value, was '{value}'
• invalid `InstrumentClass` enum string value, was '{value}'
• invalid `BarAggregation` enum string value, was '{value}'
• invalid `BookAction` enum string value, was '{value}'

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/5cac586d5ace6db9. Report an issue: GitHub.