Constraints

Constraints are a powerful feature in Typhoon that allow you to declaratively define validation logic for your instruction accounts. They are used within the #[context] macro.

Basic Usage

Constraints are added using the #[constraint(...)] attribute on fields in your context struct.

#![allow(unused)]
fn main() {
#[context]
pub struct InitContext {
    pub payer: Mut<Signer>,
    #[constraint(
        init,
        payer = payer,
    )]
    pub counter: Mut<SignerNoCheck<Account<Counter>>>,
    pub system: Program<System>,
}
}

Common Constraints

• init: Marks an account to be initialized. Requires a payer.
• payer = <field>: Specifies which account pays for the creation of an initialized account.
• seeds = [...]: Defines the seeds for a Program Derived Address (PDA).
• bump = <value>: Sets or validates the bump for a PDA.
• owner = <address>: Ensures the account is owned by a specific program.

Constraints significantly reduce boilerplate and make your programs more secure by centralizing validation logic.