Transfer hook support

[syaringan357]

https://github.com/raydium-io/raydium-cp-swap/blob/master/programs/cp-swap/src/utils/token.rs

pub fn is_supported_mint(mint_account: &InterfaceAccount<Mint>) -> Result<bool> {
    let mint_info = mint_account.to_account_info();
    if *mint_info.owner == Token::id() {
        return Ok(true);
    }
    let mint_whitelist: HashSet<&str> = MINT_WHITELIST.into_iter().collect();
    if mint_whitelist.contains(mint_account.key().to_string().as_str()) {
        return Ok(true);
    }
    let mint_data = mint_info.try_borrow_data()?;
    let mint = StateWithExtensions::<spl_token_2022::state::Mint>::unpack(&mint_data)?;
    let extensions = mint.get_extension_types()?;
    for e in extensions {
        if e != ExtensionType::TransferFeeConfig
            && e != ExtensionType::MetadataPointer
            && e != ExtensionType::TokenMetadata
            && e != ExtensionType::InterestBearingConfig
            && e != ExtensionType::ScaledUiAmount
        {
            return Ok(false);
        }
    }
    Ok(true)
}

In this code, tokens using the Token2022 standard with transfer hooks will not be supported. However, if I wanted to develop a launch platform and restrict users from creating liquidity pools with the tokens before migration, I would use a transfer hook. Then, I would set the transfer hook to "none" during the migration. But this approach will not be supported on Raydium. But some other AMMs do it this way.

pub fn is_supported_mint(mint_account: &InterfaceAccount<Mint>) -> Result<bool> {
    let mint_info = mint_account.to_account_info();
    if *mint_info.owner == Token::id() {
        return Ok(true);
    }

    if spl_token_2022::native_mint::check_id(&mint_account.key()) {
        return Err(PoolError::UnsupportNativeMintToken2022.into());
    }

    let mint_data = mint_info.try_borrow_data()?;
    let mint = StateWithExtensions::<spl_token_2022::state::Mint>::unpack(&mint_data)?;
    let extensions = mint.get_extension_types()?;

    for e in extensions {
        match e {
            ExtensionType::TransferFeeConfig
            | ExtensionType::MetadataPointer
            | ExtensionType::TokenMetadata => {
                // permissionless supported
            }
            ExtensionType::TransferHook => {
                if let Ok(transfer_hook) =
                    mint.get_extension::<extension::transfer_hook::TransferHook>()
                {
                    let transfer_hook_program_id = Option::<Pubkey>::from(transfer_hook.program_id);
                    let transfer_hook_authority = Option::<Pubkey>::from(transfer_hook.authority);
                    if transfer_hook_program_id.is_some() || transfer_hook_authority.is_some() {
                        return Ok(false);
                    }
                } else {
                    return Ok(false);
                }
            }

            _ => return Ok(false),
        }
    }
    Ok(true)
}

[0x777A]

Yes, we currently do not support token-2022 tokens with the transfer_hook extension because transfer_hook introduces some non-deterministic and uncontrollable security factors, as well as design complexity. We may have plans to support it in the future.

Currently, using transfer_hook on AMMs is generally not allowed, and the other AMMs you mentioned also seem to not support it. Because once you actually set up transfer_hook_program and transfer_hook_authority, it will return false as well.

[syaringan357]

Other AMMs don't support transfer hooks, but they do support setting the transfer_hook_program and transfer_hook_authority of the transfer hook to none before creating the liquidity pool. Please take another look at the code I wrote for you above.