pub trait FunctionError {
// Required method
fn panic(&self) -> !;
}Expand description
Enables contract runtime to panic with the given type. Any error type used in conjunction
with #[handle_result] has to implement this trait.
Example:
use near_sdk::{FunctionError, near};
enum Error {
NotFound,
Unexpected { message: String },
}
impl FunctionError for Error {
fn panic(&self) -> ! {
match self {
Error::NotFound =>
near_sdk::env::panic_str("not found"),
Error::Unexpected { message } =>
near_sdk::env::panic_str(&format!("unexpected error: {}", message))
}
}
}
#[near(contract_state)]
#[derive(Default)]
pub struct Contract;
#[near]
impl Contract {
// if the Error does not implement FunctionError, the following will not compile with #[handle_result]
#[handle_result]
pub fn set(&self, value: String) -> Result<String, Error> {
Err(Error::NotFound)
}
}