pallet-evm: avoid double fee payment (paritytech#6858)

* pallet-evm: avoid double fee payment

* Only skip fee payment for successful calls

Author: sorpaas

frame/evm/src/lib.rs

@@ -33,13 +33,12 @@ use codec::{Encode, Decode};
 #[cfg(feature = "std")]
 use serde::{Serialize, Deserialize};
 use frame_support::{ensure, decl_module, decl_storage, decl_event, decl_error};
-use frame_support::weights::Weight;
+use frame_support::weights::{Weight, Pays};
 use frame_support::traits::{Currency, ExistenceRequirement, Get};
+use frame_support::dispatch::DispatchResultWithPostInfo;
 use frame_system::RawOrigin;
 use sp_core::{U256, H256, H160, Hasher};
-use sp_runtime::{
-	DispatchResult, AccountId32, traits::{UniqueSaturatedInto, SaturatedConversion, BadOrigin},
-};
+use sp_runtime::{AccountId32, traits::{UniqueSaturatedInto, SaturatedConversion, BadOrigin}};
 use sha3::{Digest, Keccak256};
 pub use evm::{ExitReason, ExitSucceed, ExitError, ExitRevert, ExitFatal};
 use evm::Config;
@@ -325,7 +324,7 @@ decl_module! {
 			gas_limit: u32,
 			gas_price: U256,
 			nonce: Option<U256>,
-		) -> DispatchResult {
+		) -> DispatchResultWithPostInfo {
 			T::CallOrigin::ensure_address_origin(&source, origin)?;
 
 			match Self::execute_call(
@@ -346,7 +345,7 @@ decl_module! {
 				},
 			}
 
-			Ok(())
+			Ok(Pays::No.into())
 		}
 
 		/// Issue an EVM create operation. This is similar to a contract creation transaction in
@@ -360,7 +359,7 @@ decl_module! {
 			gas_limit: u32,
 			gas_price: U256,
 			nonce: Option<U256>,
-		) -> DispatchResult {
+		) -> DispatchResultWithPostInfo {
 			T::CallOrigin::ensure_address_origin(&source, origin)?;
 
 			match Self::execute_create(
@@ -380,7 +379,7 @@ decl_module! {
 				},
 			}
 
-			Ok(())
+			Ok(Pays::No.into())
 		}
 
 		/// Issue an EVM create2 operation.
@@ -394,7 +393,7 @@ decl_module! {
 			gas_limit: u32,
 			gas_price: U256,
 			nonce: Option<U256>,
-		) -> DispatchResult {
+		) -> DispatchResultWithPostInfo {
 			T::CallOrigin::ensure_address_origin(&source, origin)?;
 
 			match Self::execute_create2(
@@ -415,7 +414,7 @@ decl_module! {
 				},
 			}
 
-			Ok(())
+			Ok(Pays::No.into())
 		}
 	}
 }