Forward the result in a sudo call (#2594)

* Forward the result in a sudo call

* Print the error of the wrapped call in `sudo`

substrate/node/runtime/wasm/Cargo.lock

@@ -2481,6 +2481,7 @@ version = "2.0.0"
 dependencies = [
  "parity-codec 3.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sr-io 2.0.0",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
  "srml-support 2.0.0",

substrate/srml/sudo/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2018"
 serde = { version = "1.0", optional = true }
 parity-codec = { version = "3.3", default-features = false, features = ["derive"] }
 sr-std = { path = "../../core/sr-std", default-features = false }
+sr-io = { path = "../../core/sr-io", default-features = false }
 sr-primitives = { path = "../../core/sr-primitives", default-features = false }
 srml-support = { path = "../support", default-features = false }
 srml-support-procedural = { path = "../support/procedural" }
@@ -23,6 +24,7 @@ std = [
 	"serde",
 	"parity-codec/std",
 	"sr-std/std",
+	"sr-io/std",
 	"sr-primitives/std",
 	"srml-support/std",
 	"system/std",

substrate/srml/sudo/src/lib.rs

@@ -88,7 +88,10 @@
 
 use sr_std::prelude::*;
 use sr_primitives::traits::StaticLookup;
-use srml_support::{StorageValue, Parameter, Dispatchable, decl_module, decl_event, decl_storage, ensure};
+use srml_support::{
+	StorageValue, Parameter, Dispatchable, decl_module, decl_event,
+	decl_storage, ensure
+};
 use system::ensure_signed;
 
 pub trait Trait: system::Trait {
@@ -112,8 +115,15 @@ decl_module! {
 			let sender = ensure_signed(origin)?;
 			ensure!(sender == Self::key(), "only the current sudo key can sudo");
 
-			let ok = proposal.dispatch(system::RawOrigin::Root.into()).is_ok();
-			Self::deposit_event(RawEvent::Sudid(ok));
+			let res = match proposal.dispatch(system::RawOrigin::Root.into()) {
+				Ok(_) => true,
+				Err(e) => {
+					sr_io::print(e);
+					false
+				}
+			};
+
+			Self::deposit_event(RawEvent::Sudid(res));
 		}
 
 		/// Authenticates the current sudo key and sets the given AccountId (`new`) as the new sudo key.