why do `coin::initialize` enforce `coin_address<CoinType> == account_addr`?

Question

In coin.move:

assert!(
    coin_address<CoinType>() == account_addr,
    error::invalid_argument(ECOIN_INFO_ADDRESS_MISMATCH),
);

My guess is it prevents account A from initializing coins on behalf of account B to avoid scam?

But look forward to more clarification!

Answer 1

The intent is to ensure that a coin can ever be initialized once as that is how all the capabilities (burn, freeze, mint) are generated.

Specifically,

assert!(
    coin_address<CoinType>() == account_addr,
    error::invalid_argument(ECOIN_INFO_ADDRESS_MISMATCH),
);

prevents anyone other than the actual account that publishes CoinType from initializing it.

The next bit of code ensures it can only be initialized once:

assert!(
    !exists<CoinInfo<CoinType>>(account_addr),
    error::already_exists(ECOIN_INFO_ALREADY_PUBLISHED),
);