ts-sdk your_coin.ts example why not FA transfer

[daorren]

Discord user ID

0xdaorren

Describe your question in detail.

I use examples/your_coin.ts in ts-sdk to create new coin in testnet
this is a transfer tx from alice to bob: https://explorer.aptoslabs.com/txn/1219219381/userTxnOverview?network=testnet
my question is, why this tx uses a coin_store rather than a primary_fungible_store

according to this line https://github.com/aptos-labs/aptos-core/blob/702abf46cf4937f130d0d257815a9efdf8c05d25/aptos-move/framework/aptos-framework/sources/coin.move#L875
when coin::deposit(which used by aptos_account::deposit), if coin_store not found on receiver's address, primary_fungible_store should be created and used
bob, in this case is new account for mooncoin, so there's no coinstore for mooncoin, and is supposed to use a primary_fungible_store. however, coinstore is used, which I can't understand

What error, if any, are you getting?

No response

What have you tried or looked at? Or how can we reproduce the error?

code

Which operating system are you using?

macOS

Which SDK or tool are you using? (if any)

TypeScript SDK

Describe your environment or tooling in detail

No response

[kshitijc1506]

Hey, so you're on the right track.

aptos_account::transfer_coins -> deposit_coins -> is_account_registered -> register -> deposit

Since the account wasn't registered for the Coin, and the migrated Primary Fungible Store (PFS) doesn't exist for the account, we register the account for the Coin Type. Therefore, the Coin Store does exist for the account.

[kshitijc1506]

Also, this is a bit of extra info if you're curious:

If you call directly into coin::transfer, this will not work since the FA Metadata object hasn't been paired to the Coin type. Also, if that passes, the MigrationFlag resource also needs to be moved to the to account's PFS.

This will be handled by Labs soon in coin::deposit/withdraw, so developers and users won't have to worry about it. However, it hasn't been implemented yet.