contracterror_enum.md

contracterror_enum — Missing #[contracterror] or unstable repr on error enum

Code	SANCT_CONTRACTERROR_ENUM
Category	logic
Severity	Warning
Source rule	rules/contracterror_enum.rs

What it catches

Flags public functions returning a Result where the error type is an enum missing the #[contracterror] attribute or missing a stable #[repr(...)] (like #[repr(u32)]). Unstable or non-contract error types break client decoding of errors on the Soroban network.

Vulnerable example

pub enum Error {
    AuthFailed = 1,
}

#[contractimpl]
impl Token {
    pub fn do_thing(env: Env) -> Result<(), Error> {
        Err(Error::AuthFailed)
    }
}

The fix

Annotate the error enum with #[contracterror] and a stable #[repr(...)]:

#[contracterror]
#[repr(u32)]
pub enum Error {
    AuthFailed = 1,
}

#[contractimpl]
impl Token {
    pub fn do_thing(env: Env) -> Result<(), Error> {
        Err(Error::AuthFailed)
    }
}

How Sanctifier detects it

The detector visits all enum declarations, tracking which have #[contracterror] and #[repr]. It then visits all pub fn functions returning Result<T, E>. If E is a local enum that lacks these attributes, it flags the function.