contracts: Make ChainExtension trait generic over the runtime (#8003)

Author: athei

frame/contracts/src/chain_extension.rs

@@ -63,7 +63,7 @@ use sp_std::{
 pub use frame_system::Config as SysConfig;
 pub use pallet_contracts_primitives::ReturnFlags;
 pub use sp_core::crypto::UncheckedFrom;
-pub use crate::exec::Ext;
+pub use crate::{Config, exec::Ext};
 pub use state::Init as InitState;
 
 /// Result that returns a [`DispatchError`] on error.
@@ -74,7 +74,7 @@ pub type Result<T> = sp_std::result::Result<T, DispatchError>;
 /// In order to create a custom chain extension this trait must be implemented and supplied
 /// to the pallet contracts configuration trait as the associated type of the same name.
 /// Consult the [module documentation](self) for a general explanation of chain extensions.
-pub trait ChainExtension {
+pub trait ChainExtension<C: Config> {
 	/// Call the chain extension logic.
 	///
 	/// This is the only function that needs to be implemented in order to write a
@@ -91,8 +91,9 @@ pub trait ChainExtension {
 	/// In case of `Err` the contract execution is immediately suspended and the passed error
 	/// is returned to the caller. Otherwise the value of [`RetVal`] determines the exit
 	/// behaviour.
-	fn call<E: Ext>(func_id: u32, env: Environment<E, InitState>) -> Result<RetVal>
+	fn call<E>(func_id: u32, env: Environment<E, InitState>) -> Result<RetVal>
 	where
+		E: Ext<T = C>,
 		<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>;
 
 	/// Determines whether chain extensions are enabled for this chain.
@@ -108,9 +109,10 @@ pub trait ChainExtension {
 }
 
 /// Implementation that indicates that no chain extension is available.
-impl ChainExtension for () {
-	fn call<E: Ext>(_func_id: u32, mut _env: Environment<E, InitState>) -> Result<RetVal>
+impl<C: Config> ChainExtension<C> for () {
+	fn call<E>(_func_id: u32, mut _env: Environment<E, InitState>) -> Result<RetVal>
 	where
+		E: Ext<T = C>,
 		<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>,
 	{
 		// Never called since [`Self::enabled()`] is set to `false`. Because we want to

frame/contracts/src/lib.rs

@@ -337,7 +337,7 @@ pub trait Config: frame_system::Config {
 	type WeightInfo: WeightInfo;
 
 	/// Type that allows the runtime authors to add new host functions for a contract to call.
-	type ChainExtension: chain_extension::ChainExtension;
+	type ChainExtension: chain_extension::ChainExtension<Self>;
 
 	/// The maximum number of tries that can be queued for deletion.
 	type DeletionQueueDepth: Get<u32>;

frame/contracts/src/tests.rs

@@ -143,9 +143,10 @@ impl Default for TestExtension {
 	}
 }
 
-impl ChainExtension for TestExtension {
-	fn call<E: Ext>(func_id: u32, env: Environment<E, InitState>) -> ExtensionResult<RetVal>
+impl ChainExtension<Test> for TestExtension {
+	fn call<E>(func_id: u32, env: Environment<E, InitState>) -> ExtensionResult<RetVal>
 	where
+		E: Ext<T = Test>,
 		<E::T as SysConfig>::AccountId: UncheckedFrom<<E::T as SysConfig>::Hash> + AsRef<[u8]>,
 	{
 		match func_id {