apollo_gateway: make StatefulTransactionValidatorTrait async

[itamar-starkware]

Refactored the StatefulTransactionValidator to use async/await instead of spawning blocking tasks for each validation step.

What changed?

• Removed the need to pass a runtime handle to extract_state_nonce_and_run_validations
• Restructured the validation flow to be fully async, only using spawn_blocking for the CPU-intensive blockifier validation
• Simplified the validator initialization by deferring the creation of the blockifier validator until needed
• Split validation into clearer phases with run_pre_validation_checks and run_validate_entry_point
• Removed dependency on the blockifier's block_info() method, using the gateway's block info provider instead
• Updated tests to match the new async validation flow

Why make this change?

This refactoring improves code clarity and performance by:

• Using async/await for most operations, reducing the number of thread context switches
• Only using blocking tasks for CPU-intensive operations that can't be made async
• Creating a cleaner separation between validation phases
• Making the code more maintainable by removing unnecessary indirection through the blockifier validator

The change preserves all existing validation logic while making the code structure more straightforward and efficient.

[reviewable-StarkWare]

This change is 

[itamar-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• apollo_gateway: make StatefulTransactionValidatorTrait async #10621 👈 (View in Graphite)
• apollo_gateway: remove processing tx block #10592
• main-v0.14.1

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[ArniStarkware]

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @itamar-starkware and @TzahiTaub)

---

crates/apollo_gateway/src/gateway.rs line 161 at r1 (raw file):

        let nonce = stateful_transaction_validator
            .extract_state_nonce_and_run_validations(&executable_tx, self.mempool_client.clone())
            .await?;

I didn't start looking at the PR yet.
I do like this interface, and it is clean and good (to say the least).

If it makes things simpler, we can:

Suggestion:

        let nonce = stateful_tx_validator_factory
            .instantiate_validator_extract_state_nonce_and_run_validations(self.state_reader_factory.clone(), &executable_tx, self.mempool_client.clone())
            .await?;

[ArniStarkware]

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @itamar-starkware and @TzahiTaub)

---

crates/apollo_gateway/src/gateway.rs line 161 at r1 (raw file):

Previously, ArniStarkware (Arnon Hod) wrote…

I didn't start looking at the PR yet.
I do like this interface, and it is clean and good (to say the least).

If it makes things simpler, we can:

For the record.

[ArniStarkware]

@ArniStarkware reviewed 2 of 4 files at r1.
Reviewable status: 2 of 4 files reviewed, 1 unresolved discussion (waiting on @itamar-starkware and @TzahiTaub)

[ArniStarkware]

Reviewable status: 2 of 4 files reviewed, 3 unresolved discussions (waiting on @itamar-starkware and @TzahiTaub)

---

crates/apollo_gateway/src/stateful_transaction_validator.rs line 111 at r1 (raw file):

    // Consumed when running the CPU-heavy blockifier validation.
    state_reader_and_contract_manager:
        Option<StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>>>,

Connects to this comment

Suggestion:

    // TODO(Itamar): Fix this. The whole `StatefulTransactionValidator` is never used after `state_reader_and_contract_manager` is taken.
    // Make it non-optional and discard the instance after use.
    // Consumed when running the CPU-heavy blockifier validation.
    state_reader_and_contract_manager:
        Option<StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>>>,

---

crates/apollo_gateway/src/stateful_transaction_validator.rs line 113 at r1 (raw file):

        Option<StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>>>,
    gateway_fixed_block_state_reader: Box<dyn GatewayFixedBlockStateReader>,
}

Make the interface clear and safe.
(Not as important as the fields are not public.

Suggestion:

pub struct StatefulTransactionValidator {
    config: StatefulTransactionValidatorConfig,
    chain_info: ChainInfo,
    // Consumed when running the CPU-heavy blockifier validation.
    state_reader_and_contract_manager:
        Option<StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>>>,
    gateway_fixed_block_state_reader: Box<dyn GatewayFixedBlockStateReader>,
}

impl StatefulTransactionValidator {
    // Itamar - note `state_reader_and_contract_manager` is not optional.
    fn new(..., state_reader_and_contract_manager:
        StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>>, ...) -> Self {..}
    }
    
    fn take_state_reader_and_contract_manager(&mut self) -> StateReaderAndContractManager<Box<dyn GatewayStateReaderWithCompiledClasses>> {
        self.state_reader_and_contract_manager.take().expect("Validator was already consumed");
    }
}

[ArniStarkware]

Reviewable status: 1 of 4 files reviewed, 3 unresolved discussions (waiting on @itamar-starkware and @TzahiTaub)

---

crates/apollo_gateway/src/stateful_transaction_validator.rs line 113 at r1 (raw file):

Previously, ArniStarkware (Arnon Hod) wrote…

Make the interface clear and safe.
(Not as important as the fields are not public.

Note, both these functions are not public.

[ArniStarkware]

crates/apollo_gateway/src/stateful_transaction_validator.rs line 306 at r2 (raw file):

    }

    async fn run_pre_validation_checks(

Document this function and/or rename it.

Suggestion:

    async fn extract_state_nonce_and_run_pre_validation_checks(

[ArniStarkware]

crates/apollo_gateway/src/stateful_transaction_validator_test.rs line 53 at r2 (raw file):

        state_reader_and_contract_manager: None,
        gateway_fixed_block_state_reader: Box::new(mock_gateway_fixed_block),
    };

Cool hack. We can now create a StatefulTransactionValidator without a state reader for testing, as the state reader is irrelevant in this context.

It does make me think that there should be a
StatefulTransactionPreValidator that would not have a state_reader_and_contract_manager...

Code quote:

    let stateful_validator = StatefulTransactionValidator {
        config: StatefulTransactionValidatorConfig::default(),
        chain_info: ChainInfo::create_for_testing(),
        state_reader_and_contract_manager: None,
        gateway_fixed_block_state_reader: Box::new(mock_gateway_fixed_block),
    };

[itamar-starkware]

crates/apollo_gateway/src/stateful_transaction_validator_test.rs line 352 at r1 (raw file):

    account_nonce: Nonce,
    max_allowed_nonce_gap: u32,
    expected_result_code: Result<(), StarknetErrorCode>,

offline discussion with Arni about this suggestion:

Suggestion:

expected_result_code: Result<Nonce, StarknetErrorCode>,

[itamar-starkware]

crates/apollo_gateway/src/stateful_transaction_validator.rs line 306 at r2 (raw file):

Previously, ArniStarkware (Arnon Hod) wrote…

Document this function and/or rename it.

We decided to split into two functions here.
extract_state_nonce
run_pre_validation_checks

[itamar-starkware]

crates/apollo_gateway/src/stateful_transaction_validator.rs line 113 at r1 (raw file):

Previously, ArniStarkware (Arnon Hod) wrote…

Note, both these functions are not public.

Done