Don't use Ext outside of runtime!!! (#704)

Author: gavofyork

substrate/client/src/call_executor.rs

@@ -20,7 +20,6 @@ use runtime_primitives::generic::BlockId;
 use runtime_primitives::traits::Block as BlockT;
 use state_machine::{self, OverlayedChanges, Ext,
 	CodeExecutor, ExecutionManager, native_when_possible};
-use runtime_io::Externalities;
 use executor::{RuntimeVersion, RuntimeInfo};
 use patricia_trie::NodeCodec;
 use hashdb::Hasher;
@@ -143,12 +142,17 @@ where
 	fn runtime_version(&self, id: &BlockId<Block>) -> error::Result<RuntimeVersion> {
 		let mut overlay = OverlayedChanges::default();
 		let state = self.backend.state_at(*id)?;
-		let mut externalities = Ext::new(&mut overlay, &state);
-		let code = externalities.storage(b":code").ok_or(error::ErrorKind::VersionInvalid)?
+		use state_machine::Backend;
+		let code = state.storage(b":code")
+			.map_err(|e| error::ErrorKind::Execution(Box::new(e)))?
+			.ok_or(error::ErrorKind::VersionInvalid)?
 			.to_vec();
-		let heap_pages = externalities.storage(b":heappages").and_then(|v| u64::decode(&mut &v[..])).unwrap_or(8) as usize;
+		let heap_pages = state.storage(b":heappages")
+			.map_err(|e| error::ErrorKind::Execution(Box::new(e)))?
+			.and_then(|v| u64::decode(&mut &v[..]))
+			.unwrap_or(8) as usize;
 
-		self.executor.runtime_version(&mut externalities, heap_pages, &code)
+		self.executor.runtime_version(&mut Ext::new(&mut overlay, &state), heap_pages, &code)
 			.ok_or(error::ErrorKind::VersionInvalid.into())
 	}