anchor: how to init a PDA and close it in the same method?

Question

I would like to create a PDA and close it in the same method, but can't find how.

if i use init and close, it says i should add mut, but if i add mut, it says it can't be used with init.

Why do i need to create and close the account in the same method ? this account is used in a CPI to receive funds and then send them back to other accounts.

The only solution i can see is creating this account in another method before calling this one, but if i can avoid it, that would be wonderfull.

Answer 1

You can try directly modifying the lamport balance of the PDA within the instruction where you init the account.

For example,

use anchor_lang::prelude::*;
declare_id!("CShtV32yVjfxG2kyGkpTcx4jbxYm6ZJBqfakkydgdyAY");

#[program]
mod hello_anchor {
    use super::*;

    pub fn initialize(ctx: Context<Initialize>, data: u64) -> Result<()> {
        ctx.accounts.new_account.data = data;
        msg!("Changed data to: {}!", data);

        let amount = **ctx
            .accounts
            .new_account
            .to_account_info()
            .try_borrow_mut_lamports()?;

        msg!("Lamports: {}!", amount);

        **ctx
            .accounts
            .new_account
            .to_account_info()
            .try_borrow_mut_lamports()? -= amount;

        **ctx.accounts.signer.try_borrow_mut_lamports()? += amount;
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(init, payer = signer, space = 8 + 8)]
    pub new_account: Account<'info, NewAccount>,
    #[account(mut)]
    pub signer: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[account]
pub struct NewAccount {
    data: u64,
}