sim-rs: support leios-aggressive-mempool-pruning setting

Author: SupernaviX

data/simulation/config.d.ts

@@ -53,6 +53,10 @@ export interface Config {
    * The strategy to use when selecting TXs from the Leios mempool.
    */
   "leios-mempool-sampling-strategy": MempoolSamplingStrategy;
+  /**
+   * If true, transactions will be removed from the Leios mempool if they conflict with in-flight IBs.
+   */
+  "leios-mempool-aggressive-pruning": boolean;
   /**
    * Praos blockchain quality parameter.
    * This is η from the Leios paper.

data/simulation/config.default.yaml

@@ -30,6 +30,7 @@ leios-vote-send-recv-stages: false
 leios-late-ib-inclusion: true
 leios-header-diffusion-time-ms: 1000.0
 leios-mempool-sampling-strategy: ordered-by-id
+leios-mempool-aggressive-pruning: false
 # TODO: revise default
 praos-chain-quality: 40
 praos-fallback-enabled: true

sim-rs/sim-core/src/config.rs

@@ -68,6 +68,7 @@ pub struct RawParameters {
     pub leios_late_ib_inclusion: bool,
     pub leios_header_diffusion_time_ms: f64,
     pub leios_mempool_sampling_strategy: MempoolSamplingStrategy,
+    pub leios_mempool_aggressive_pruning: bool,
     pub praos_chain_quality: u64,
     pub praos_fallback_enabled: bool,
 
@@ -475,6 +476,7 @@ pub struct SimConfiguration {
     pub(crate) header_diffusion_time: Duration,
     pub(crate) relay_strategy: RelayStrategy,
     pub(crate) mempool_strategy: MempoolSamplingStrategy,
+    pub(crate) mempool_aggressive_pruning: bool,
     pub(crate) praos_chain_quality: u64,
     pub(crate) block_generation_probability: f64,
     pub(crate) ib_generation_probability: f64,
@@ -520,6 +522,7 @@ impl SimConfiguration {
             header_diffusion_time: duration_ms(params.leios_header_diffusion_time_ms),
             relay_strategy: params.relay_strategy,
             mempool_strategy: params.leios_mempool_sampling_strategy,
+            mempool_aggressive_pruning: params.leios_mempool_aggressive_pruning,
             praos_chain_quality: params.praos_chain_quality,
             block_generation_probability: params.rb_generation_probability,
             ib_generation_probability: params.ib_generation_probability,

sim-rs/sim-core/src/sim/node.rs

@@ -155,6 +155,7 @@ struct SeenTransaction {
 #[derive(Default)]
 struct NodeLeiosState {
     mempool: BTreeMap<TransactionId, SeenTransaction>,
+    input_ids_from_ibs: HashSet<u64>,
     ibs_to_generate: BTreeMap<u64, Vec<InputBlockHeader>>,
     ibs: BTreeMap<InputBlockId, InputBlockState>,
     ib_requests: BTreeMap<NodeId, PeerInputBlockRequests>,
@@ -1043,6 +1044,13 @@ impl Node {
             }
             self.send_to(*peer, SimulationMessage::AnnounceTx(id))?;
         }
+        if self.sim_config.mempool_aggressive_pruning
+            && self.leios.input_ids_from_ibs.contains(&tx.input_id)
+        {
+            // Ignoring a TX which conflicts with TXs we've seen in input blocks.
+            // This only affects the Leios mempool; these TXs should still be able to reach the chain through Praos.
+            return Ok(());
+        }
         self.leios.mempool.insert(
             tx.id,
             SeenTransaction {
@@ -1205,6 +1213,15 @@ impl Node {
             // Do not include transactions from this IB in any IBs we produce ourselves.
             self.leios.mempool.remove(&transaction.id);
         }
+        if self.sim_config.mempool_aggressive_pruning {
+            // If we're using aggressive pruning, remove transactions from the mempool if they conflict with transactions in this IB
+            self.leios
+                .input_ids_from_ibs
+                .extend(ib.transactions.iter().map(|tx| tx.input_id));
+            self.leios
+                .mempool
+                .retain(|_, seen| !self.leios.input_ids_from_ibs.contains(&seen.tx.input_id));
+        }
         if self
             .leios
             .ibs