simulacrum: ensure determinism when using a seeded rng

Author: bmwill

crates/simulacrum/src/lib.rs

@@ -10,6 +10,8 @@
 //!
 //! [`Simulacrum`]: crate::Simulacrum
 
+use std::num::NonZeroUsize;
+
 use anyhow::{anyhow, Result};
 use rand::rngs::OsRng;
 use sui_config::{genesis, transaction_deny_config::TransactionDenyConfig};
@@ -91,6 +93,7 @@ where
         let config = ConfigBuilder::new_with_temp_dir()
             .rng(&mut rng)
             .with_chain_start_timestamp_ms(1)
+            .deterministic_committee_size(NonZeroUsize::new(1).unwrap())
             .build();
         let keystore = KeyStore::from_newtork_config(&config);
         let store = InMemoryStore::new(&config.genesis);
@@ -358,6 +361,7 @@ impl<'a> CommitteeWithKeys<'a> {
 mod tests {
     use std::time::Duration;
 
+    use rand::{rngs::StdRng, SeedableRng};
     use shared_crypto::intent::Intent;
     use sui_types::{
         base_types::SuiAddress,
@@ -369,6 +373,36 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn deterministic_genesis() {
+        let rng = StdRng::from_seed([9; 32]);
+        let chain1 = Simulacrum::new_with_rng(rng);
+        let genesis_checkpoint_digest1 = chain1
+            .store()
+            .get_checkpoint_by_sequence_number(0)
+            .unwrap()
+            .digest();
+
+        let rng = StdRng::from_seed([9; 32]);
+        let chain2 = Simulacrum::new_with_rng(rng);
+        let genesis_checkpoint_digest2 = chain2
+            .store()
+            .get_checkpoint_by_sequence_number(0)
+            .unwrap()
+            .digest();
+
+        assert_eq!(genesis_checkpoint_digest1, genesis_checkpoint_digest2);
+
+        // Ensure the committees are different when using different seeds
+        let rng = StdRng::from_seed([0; 32]);
+        let chain3 = Simulacrum::new_with_rng(rng);
+
+        assert_ne!(
+            chain1.store().get_committee_by_epoch(0),
+            chain3.store().get_committee_by_epoch(0),
+        );
+    }
+
     #[test]
     fn simple() {
         let steps = 10;

crates/sui-swarm-config/src/network_config_builder.rs

@@ -20,6 +20,9 @@ pub enum CommitteeConfig {
     Size(NonZeroUsize),
     Validators(Vec<ValidatorGenesisConfig>),
     AccountKeys(Vec<AccountKeyPair>),
+    /// Indicates that a committee should be deterministically generated, useing the provided rng
+    /// as a source of randomness as well as generating deterministic network port information.
+    Deterministic(NonZeroUsize),
 }
 
 pub type SupportedProtocolVersionsCallback = Arc<
@@ -86,6 +89,11 @@ impl<R> ConfigBuilder<R> {
         self
     }
 
+    pub fn deterministic_committee_size(mut self, committee_size: NonZeroUsize) -> Self {
+        self.committee = CommitteeConfig::Deterministic(committee_size);
+        self
+    }
+
     pub fn with_validator_account_keys(mut self, keys: Vec<AccountKeyPair>) -> Self {
         self.committee = CommitteeConfig::AccountKeys(keys);
         self
@@ -232,6 +240,20 @@ impl<R: rand::RngCore + rand::CryptoRng> ConfigBuilder<R> {
                     })
                     .collect::<Vec<_>>()
             }
+            CommitteeConfig::Deterministic(size) => {
+                let mut configs = vec![];
+                for i in 0..size.into() {
+                    let port_offset = 8000 + i * 10;
+                    let mut builder = ValidatorGenesisConfigBuilder::new()
+                        .with_ip("127.0.0.1".to_owned())
+                        .with_deterministic_ports(port_offset as u16);
+                    if let Some(rgp) = self.reference_gas_price {
+                        builder = builder.with_gas_price(rgp);
+                    }
+                    configs.push(builder.build(&mut rng));
+                }
+                configs
+            }
         };
 
         let genesis_config = self