Token type is !Send + !Sync

[greged93]

The Token type in token/client/src/token.rs seems to have been designed in order to be Send + Sync, given the fact that Arc was used for the different fields. However, marker traits Send + Sync are not added to the traits objects and as such fails Token fails to capture this feature.

I'm willing to implement this if the issue is accepted.

[buffalojoec]

Hey there, are you talking about right here?

solana-program-library/token/client/src/token.rs

Lines 383 to 386 in ce0389b

	impl<T> Token<T>
	where
	T: SendTransaction + SimulateTransaction,
	{

And could you maybe elaborate on what the motivation would be to add this change? It's not immediately clear from the description.

Thanks!

[greged93]

hey @buffalojoec, I was talking about the type below. From what I can see from the fields, it seems like the type was made in order to be Send + Sync? Otherwise why use Arc for client, payer,... ? I think we could make Token thread-safe by adding Send + Sync as a bounds for client, payer and nonce_authority.

solana-program-library/token/client/src/token.rs

Lines 331 to 342 in ce0389b

	pub struct Token<T> {
	client: Arc<dyn ProgramClient<T>>,
	pubkey: Pubkey, /* token mint */
	decimals: Option<u8>,
	payer: Arc<dyn Signer>,
	program_id: Pubkey,
	nonce_account: Option<Pubkey>,
	nonce_authority: Option<Arc<dyn Signer>>,
	nonce_blockhash: Option<Hash>,
	memo: Arc<RwLock<Option<TokenMemo>>>,
	transfer_hook_accounts: Option<Vec<AccountMeta>>,
	}

[buffalojoec]

@greged93 Sorry I'm just getting back here!

Yeah I think making Token thread-safe makes sense. If you think it's important go for it!

[greged93]

Great! Can you assign the issue?

[1500256797]

Why can't we directly send Token between threads? I think this is necessary to fully utilize multithreading

[1500256797]

If ProgramClient cannot be sent or synchronized directly between threads, how should it be handled in concurrent scenarios? I believe it needs to be implemented with the Send and Sync traits to address multithreading concurrency issues.