Use saturating_add

radix-engine/src/vm/wasm_runtime/scrypto_runtime.rs

@@ -39,7 +39,6 @@ impl<'y, Y: SystemApi<RuntimeError>> ScryptoRuntime<'y, Y> {
             // Add 7,000 base units to make sure the we do not undercharge for WASM execution,
             // which might lead to system exploitation.
             // This is especially important in corner-cases such as `costing::spin_loop_v2` benchmark.
-            // Use larger cost unit buffer to call `consume_wasm_execution_exceeding_buffer`
             // less frequently.
             7000
         };
@@ -55,7 +54,6 @@ impl<'y, Y: SystemApi<RuntimeError>> ScryptoRuntime<'y, Y> {
             wasm_execution_units_base,
         }
     }
-
     pub fn parse_blueprint_id(
         package_address: Vec<u8>,
         blueprint_name: Vec<u8>,
@@ -74,9 +72,9 @@ impl<'y, Y: SystemApi<RuntimeError>> ScryptoRuntime<'y, Y> {
     ) -> Result<(), InvokeError<WasmRuntimeError>> {
         assert!(n > self.wasm_execution_units_buffer);
         let n_remaining_after_buffer_used = n - self.wasm_execution_units_buffer;
-        let amount_to_request = n_remaining_after_buffer_used
-            .checked_add(WASM_EXECUTION_COST_UNITS_BUFFER)
-            .unwrap_or(u32::MAX);
+        let amount_to_request =
+            n_remaining_after_buffer_used.saturating_add(WASM_EXECUTION_COST_UNITS_BUFFER);
+
         self.api
             .consume_cost_units(ClientCostingEntry::RunWasmCode {
                 package_address: &self.package_address,
@@ -416,9 +414,7 @@ impl<'y, Y: SystemApi<RuntimeError>> WasmRuntime for ScryptoRuntime<'y, Y> {
         &mut self,
         n: u32,
     ) -> Result<(), InvokeError<WasmRuntimeError>> {
-        let n = n
-            .checked_add(self.wasm_execution_units_base)
-            .unwrap_or(u32::MAX);
+        let n = n.saturating_add(self.wasm_execution_units_base);
 
         if n <= self.wasm_execution_units_buffer {
             self.wasm_execution_units_buffer -= n;