Extend cost params in simulation in order to match the hardcoded valu…

…e. (#1405)

### What

Extend cost params in simulation in order to match the hardcoded value.

### Why

Env expects cost params to have the same size as defined in XDR, even if
protocol doesn't use these params yet. This is a temporary workaround
until #1388 is resolved.

### Known limitations

N/A

soroban-simulation/src/network_config.rs

@@ -5,8 +5,9 @@ use soroban_env_host::fees::{
     compute_write_fee_per_1kb, FeeConfiguration, RentFeeConfiguration, WriteFeeConfiguration,
 };
 use soroban_env_host::xdr::{
-    ConfigSettingEntry, ConfigSettingId, ContractCostParams, LedgerEntry, LedgerEntryData,
-    LedgerKey, LedgerKeyConfigSetting,
+    ConfigSettingEntry, ConfigSettingId, ContractCostParamEntry, ContractCostParams,
+    ContractCostType, ExtensionPoint, LedgerEntry, LedgerEntryData, LedgerKey,
+    LedgerKeyConfigSetting,
 };
 use soroban_env_host::LedgerInfo;
 use std::rc::Rc;
@@ -49,6 +50,24 @@ fn load_configuration_setting(
     }
 }
 
+fn extend_cost_params(params: &mut ContractCostParams) -> Result<()> {
+    let target_size = ContractCostType::variants().len();
+    if params.0.len() >= target_size {
+        return Ok(());
+    }
+    let mut v = params.to_vec();
+    v.resize(
+        target_size,
+        ContractCostParamEntry {
+            ext: ExtensionPoint::V0,
+            const_term: 0,
+            linear_term: 0,
+        },
+    );
+    params.0 = v.try_into().context("too many contract cost params")?;
+    Ok(())
+}
+
 macro_rules! load_setting {
     ($snapshot:ident, $enum_variant:ident) => {
         match load_configuration_setting($snapshot, ConfigSettingId::$enum_variant)? {
@@ -76,8 +95,13 @@ impl NetworkConfig {
         let events = load_setting!(snapshot, ContractEventsV0);
         let bandwidth = load_setting!(snapshot, ContractBandwidthV0);
         let state_archival = load_setting!(snapshot, StateArchival);
-        let cpu_cost_params = load_setting!(snapshot, ContractCostParamsCpuInstructions);
-        let memory_cost_params = load_setting!(snapshot, ContractCostParamsMemoryBytes);
+        let mut cpu_cost_params = load_setting!(snapshot, ContractCostParamsCpuInstructions);
+        let mut memory_cost_params = load_setting!(snapshot, ContractCostParamsMemoryBytes);
+        // This is a hack to get around env using hardcoded cost param length
+        // instead of the protocol-defined length:
+        // https://github.com/stellar/rs-soroban-env/issues/1388.
+        extend_cost_params(&mut cpu_cost_params)?;
+        extend_cost_params(&mut memory_cost_params)?;
 
         let write_fee_configuration = WriteFeeConfiguration {
             bucket_list_target_size_bytes: ledger_cost.bucket_list_target_size_bytes,

soroban-simulation/src/test/network_config.rs

@@ -133,6 +133,20 @@ fn test_load_config_from_snapshot() {
         NetworkConfig::load_from_snapshot(&snapshot_source, 150_000_000_000_000).unwrap();
     // From tests/resources `test_compute_write_fee`
     let write_fee = 1_000_000_000 + 50 * (1_000_000_000_i64 - 1_000_000) / 2;
+
+    let empty_entry = ContractCostParamEntry {
+        ext: ExtensionPoint::V0,
+        const_term: 0,
+        linear_term: 0,
+    };
+    let mut expected_cpu_cost_params_vec = cpu_cost_params.to_vec();
+    expected_cpu_cost_params_vec.resize(ContractCostType::variants().len(), empty_entry.clone());
+    let expected_cpu_cost_params =
+        ContractCostParams(expected_cpu_cost_params_vec.try_into().unwrap());
+    let mut expected_mem_cost_params_vec = memory_cost_params.to_vec();
+    expected_mem_cost_params_vec.resize(ContractCostType::variants().len(), empty_entry.clone());
+    let expected_mem_cost_params =
+        ContractCostParams(expected_mem_cost_params_vec.try_into().unwrap());
     assert_eq!(
         network_config,
         NetworkConfig {
@@ -154,8 +168,8 @@ fn test_load_config_from_snapshot() {
             },
             tx_max_instructions: 2,
             tx_memory_limit: 4,
-            cpu_cost_params,
-            memory_cost_params,
+            cpu_cost_params: expected_cpu_cost_params,
+            memory_cost_params: expected_mem_cost_params,
             min_temp_entry_ttl: 27,
             min_persistent_entry_ttl: 28,
             max_entry_ttl: 26,