Merge pull request #1465 from oasisprotocol/kostko/fix/subcall-gas-ev…

…ents

runtime-sdk: Do not emit gas used events for subcalls

runtime-sdk/modules/evm/src/precompile/subcall.rs

@@ -307,6 +307,17 @@ mod test {
         assert_eq!(event.from, Address::from_eth(contract_address.as_ref()));
         assert_eq!(event.to, keys::alice::address());
         assert_eq!(event.amount, BaseUnits::new(1_000, Denomination::NATIVE));
+
+        // Make sure only one gas used event was emitted (e.g. subcall should not emit its own gas
+        // used events).
+        #[derive(Debug, Default, cbor::Decode)]
+        struct GasUsedEvent {
+            amount: u64,
+        }
+
+        let events: Vec<GasUsedEvent> = cbor::from_slice(&tags[1].value).unwrap();
+        assert_eq!(events.len(), 1); // Just one gas used event.
+        assert_eq!(events[0].amount, 25742);
     }
 
     #[test]

runtime-sdk/src/modules/core/mod.rs

@@ -1021,8 +1021,8 @@ impl<Cfg: Config> module::TransactionHandler for Module<Cfg> {
         ctx: &mut C,
         result: module::CallResult,
     ) -> Result<module::CallResult, Error> {
-        // Emit gas used event.
-        if Cfg::EMIT_GAS_USED_EVENTS {
+        // Emit gas used event (if this is not an internally generated call).
+        if Cfg::EMIT_GAS_USED_EVENTS && !ctx.is_internal() {
             let used_gas = Self::used_tx_gas(ctx);
             ctx.emit_unconditional_event(Event::GasUsed { amount: used_gas });
         }