Remove runtime registered extensions after execution (#7236)

* Remove runtime registered extensions after execution

This prevents a bug when an extension was registered in native, but the
native execution aborted without removing the extension again. Now, when
executing the wasm code the extension is still registered and it fails
of being registered. So, the wasm execution fails as well. This can
happen for example for the `VerificationExt`.

* Make it better

substrate/primitives/state-machine/src/lib.rs

@@ -31,7 +31,7 @@ mod ext;
 mod testing;
 #[cfg(feature = "std")]
 mod basic;
-mod overlayed_changes;
+pub(crate) mod overlayed_changes;
 #[cfg(feature = "std")]
 mod proving_backend;
 mod trie_backend;
@@ -907,7 +907,7 @@ mod tests {
 			_method: &str,
 			_data: &[u8],
 			use_native: bool,
-			_native_call: Option<NC>,
+			native_call: Option<NC>,
 		) -> (CallResult<R, Self::Error>, bool) {
 			if self.change_changes_trie_config {
 				ext.place_storage(
@@ -922,8 +922,15 @@ mod tests {
 			}
 
 			let using_native = use_native && self.native_available;
-			match (using_native, self.native_succeeds, self.fallback_succeeds) {
-				(true, true, _) | (false, _, true) => {
+			match (using_native, self.native_succeeds, self.fallback_succeeds, native_call) {
+				(true, true, _, Some(call)) => {
+					let res = sp_externalities::set_and_run_with_externalities(ext, || call());
+					(
+						res.map(NativeOrEncoded::Native).map_err(|_| 0),
+						true
+					)
+				},
+				(true, true, _, None) | (false, _, true, None) => {
 					(
 						Ok(
 							NativeOrEncoded::Encoded(
@@ -1473,4 +1480,51 @@ mod tests {
 		overlay.commit_transaction().unwrap();
 		assert_eq!(overlay.storage(b"ccc"), Some(None));
 	}
+
+	#[test]
+	fn runtime_registered_extensions_are_removed_after_execution() {
+		use sp_externalities::ExternalitiesExt;
+		sp_externalities::decl_extension! {
+			struct DummyExt(u32);
+		}
+
+		let backend = trie_backend::tests::test_trie();
+		let mut overlayed_changes = Default::default();
+		let mut offchain_overlayed_changes = Default::default();
+		let wasm_code = RuntimeCode::empty();
+
+		let mut state_machine = StateMachine::new(
+			&backend,
+			changes_trie::disabled_state::<_, u64>(),
+			&mut overlayed_changes,
+			&mut offchain_overlayed_changes,
+			&DummyCodeExecutor {
+				change_changes_trie_config: false,
+				native_available: true,
+				native_succeeds: true,
+				fallback_succeeds: false,
+			},
+			"test",
+			&[],
+			Default::default(),
+			&wasm_code,
+			TaskExecutor::new(),
+		);
+
+		let run_state_machine = |state_machine: &mut StateMachine<_, _, _, _>| {
+			state_machine.execute_using_consensus_failure_handler::<fn(_, _) -> _, _, _>(
+				ExecutionManager::NativeWhenPossible,
+				Some(|| {
+					sp_externalities::with_externalities(|mut ext| {
+						ext.register_extension(DummyExt(2)).unwrap();
+					}).unwrap();
+
+					Ok(())
+				}),
+			).unwrap();
+		};
+
+		run_state_machine(&mut state_machine);
+		run_state_machine(&mut state_machine);
+	}
 }