Add a new host function for reporting fatal errors; make WASM backtraces readable when printing out errors (#10741)

* Add a new host function for reporting fatal errors

* Fix one of the wasmtime executor tests

* Have `#[runtime_interface(wasm_only)]` actually mean WASM-only, and not no_std-only

* Print out errors through `Display` instead of `Debug`

* Switch one more trait to require `Error` for its error instead of only `Debug`

* Align to review comments

substrate/frame/contracts/rpc/src/lib.rs

@@ -302,11 +302,11 @@ where
 }
 
 /// Converts a runtime trap into an RPC error.
-fn runtime_error_into_rpc_err(err: impl std::fmt::Debug) -> Error {
+fn runtime_error_into_rpc_err(err: impl std::fmt::Display) -> Error {
 	Error {
 		code: ErrorCode::ServerError(RUNTIME_ERROR),
 		message: "Runtime error".into(),
-		data: Some(format!("{:?}", err).into()),
+		data: Some(err.to_string().into()),
 	}
 }
 

substrate/frame/merkle-mountain-range/rpc/src/lib.rs

@@ -144,11 +144,11 @@ fn mmr_error_into_rpc_error(err: MmrError) -> Error {
 }
 
 /// Converts a runtime trap into an RPC error.
-fn runtime_error_into_rpc_error(err: impl std::fmt::Debug) -> Error {
+fn runtime_error_into_rpc_error(err: impl std::fmt::Display) -> Error {
 	Error {
 		code: ErrorCode::ServerError(RUNTIME_ERROR),
 		message: "Runtime trapped".into(),
-		data: Some(format!("{:?}", err).into()),
+		data: Some(err.to_string().into()),
 	}
 }
 

substrate/frame/transaction-payment/rpc/src/lib.rs

@@ -103,7 +103,7 @@ where
 		api.query_info(&at, uxt, encoded_len).map_err(|e| RpcError {
 			code: ErrorCode::ServerError(Error::RuntimeError.into()),
 			message: "Unable to query dispatch info.".into(),
-			data: Some(format!("{:?}", e).into()),
+			data: Some(e.to_string().into()),
 		})
 	}
 
@@ -127,7 +127,7 @@ where
 		let fee_details = api.query_fee_details(&at, uxt, encoded_len).map_err(|e| RpcError {
 			code: ErrorCode::ServerError(Error::RuntimeError.into()),
 			message: "Unable to query fee details.".into(),
-			data: Some(format!("{:?}", e).into()),
+			data: Some(e.to_string().into()),
 		})?;
 
 		let try_into_rpc_balance = |value: Balance| {