Add trace information to eth_estimateGas (#10519)

* Add trace information to eth_estimateGas

* replace unwrap better version

* change vm::Error formatter to more user-friendly

* remove extra error format

* use map_or instead sequence of map/unwrap_or

ethcore/src/client/client.rs

@@ -1571,22 +1571,27 @@ impl Call for Client {
 			let schedule = machine.schedule(env_info.number);
 			Executive::new(&mut clone, &env_info, &machine, &schedule)
 				.transact_virtual(&tx, options())
-				.ok()
-				.map(|r| r.exception.is_none())
 		};
 
-		let cond = |gas| exec(gas).unwrap_or(false);
+		let cond = |gas| {
+			exec(gas)
+				.ok()
+				.map_or(false, |r| r.exception.is_none())
+		};
 
 		if !cond(upper) {
 			upper = max_upper;
 			match exec(upper) {
-				Some(false) => return Err(CallError::Exceptional),
-				None => {
+				Ok(v) => {
+					if let Some(exception) = v.exception {
+						return Err(CallError::Exceptional(exception))
+					}
+				},
+				Err(_e) => {
 					trace!(target: "estimate_gas", "estimate_gas failed with {}", upper);
 					let err = ExecutionError::Internal(format!("Requires higher than upper limit of {}", upper));
 					return Err(err.into())
-				},
-				_ => {},
+				}
 			}
 		}
 		let lower = t.gas_required(&self.engine.schedule(env_info.number)).into();

ethcore/src/executed.rs

@@ -167,7 +167,7 @@ pub enum CallError {
 	/// Couldn't find requested block's state in the chain.
 	StatePruned,
 	/// Couldn't find an amount of gas that didn't result in an exception.
-	Exceptional,
+	Exceptional(vm::Error),
 	/// Corrupt state.
 	StateCorrupt,
 	/// Error executing.
@@ -187,7 +187,7 @@ impl fmt::Display for CallError {
 		let msg = match *self {
 			TransactionNotFound => "Transaction couldn't be found in the chain".into(),
 			StatePruned => "Couldn't find the transaction block's state in the chain".into(),
-			Exceptional => "An exception happened in the execution".into(),
+			Exceptional(ref e) => format!("An exception ({}) happened in the execution", e),
 			StateCorrupt => "Stored state found to be corrupted.".into(),
 			Execution(ref e) => format!("{}", e),
 		};

rpc/src/v1/helpers/errors.rs

@@ -173,11 +173,11 @@ pub fn state_corrupt() -> Error {
 	internal("State corrupt", "")
 }
 
-pub fn exceptional() -> Error {
+pub fn exceptional<T: fmt::Display>(data: T) -> Error {
 	Error {
 		code: ErrorCode::ServerError(codes::EXCEPTION_ERROR),
 		message: "The execution failed due to an exception.".into(),
-		data: None,
+		data: Some(Value::String(data.to_string())),
 	}
 }
 
@@ -467,7 +467,7 @@ pub fn call(error: CallError) -> Error {
 	match error {
 		CallError::StatePruned => state_pruned(),
 		CallError::StateCorrupt => state_corrupt(),
-		CallError::Exceptional => exceptional(),
+		CallError::Exceptional(e) => exceptional(e),
 		CallError::Execution(e) => execution(e),
 		CallError::TransactionNotFound => internal("{}, this should not be the case with eth_call, most likely a bug.", CallError::TransactionNotFound),
 	}