More decl_error! migrations (#4427)

* Update assets to `decl_error`

* Update aura to `decl_error`

* Update authority discovery to `decl_error`

* Update collective to `decl_error`

* Update evm to `decl_error!`

* Fix error with replace

* Revert "Update authority discovery to `decl_error`"

This reverts commit 26e8f3c56656963d847e984c6f2c8e1f88014899.

* Revert "Update aura to `decl_error`"

This reverts commit 8f17c44ca8375a4a755710aaab7ad4d9522c4376.

* Update democracy to `decl_error`

* Update finality-tracker to `decl_error`

* Update grandpa to `decl_error`

* `assert` to `ensure` in dispatchable function

substrate/frame/assets/src/lib.rs

@@ -84,7 +84,8 @@
 //! ### Simple Code Snippet
 //!
 //! ```rust,ignore
-//! use frame_support::{decl_module, dispatch};
+//! use pallet_assets as assets;
+//! use frame_support::{decl_module, dispatch, ensure};
 //! use frame_system::{self as system, ensure_signed};
 //!
 //! pub trait Trait: assets::Trait { }
@@ -92,14 +93,15 @@
 //! decl_module! {
 //! 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
 //! 		pub fn issue_token_airdrop(origin) -> dispatch::Result {
+//! 			let sender = ensure_signed(origin).map_err(|e| e.as_str())?;
+//!
 //! 			const ACCOUNT_ALICE: u64 = 1;
 //! 			const ACCOUNT_BOB: u64 = 2;
-//! 			const COUNT_AIRDROP_RECIPIENTS = 2;
+//! 			const COUNT_AIRDROP_RECIPIENTS: u64 = 2;
 //! 			const TOKENS_FIXED_SUPPLY: u64 = 100;
 //!
 //! 			ensure!(!COUNT_AIRDROP_RECIPIENTS.is_zero(), "Divide by zero error.");
 //!
-//! 			let sender = ensure_signed(origin)?;
 //! 			let asset_id = Self::next_asset_id();
 //!
 //! 			<NextAssetId<T>>::mutate(|asset_id| *asset_id += 1);
@@ -130,8 +132,8 @@
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use frame_support::{Parameter, decl_module, decl_event, decl_storage, ensure};
-use sp_runtime::traits::{Member, SimpleArithmetic, Zero, StaticLookup};
+use frame_support::{Parameter, decl_module, decl_event, decl_storage, decl_error, ensure};
+use sp_runtime::traits::{Member, SimpleArithmetic, Zero, StaticLookup, ModuleDispatchError};
 use frame_system::{self as system, ensure_signed};
 use sp_runtime::traits::One;
 
@@ -149,12 +151,14 @@ pub trait Trait: frame_system::Trait {
 
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		type Error = Error;
+
 		fn deposit_event() = default;
 		/// Issue a new class of fungible assets. There are, and will only ever be, `total`
 		/// such assets and they'll all belong to the `origin` initially. It will have an
 		/// identifier `AssetId` instance: this will be specified in the `Issued` event.
 		fn issue(origin, #[compact] total: T::Balance) {
-			let origin = ensure_signed(origin)?;
+			let origin = ensure_signed(origin).map_err(|e| e.as_str())?;
 
 			let id = Self::next_asset_id();
 			<NextAssetId<T>>::mutate(|id| *id += One::one());
@@ -171,12 +175,12 @@ decl_module! {
 			target: <T::Lookup as StaticLookup>::Source,
 			#[compact] amount: T::Balance
 		) {
-			let origin = ensure_signed(origin)?;
+			let origin = ensure_signed(origin).map_err(|e| e.as_str())?;
 			let origin_account = (id, origin.clone());
 			let origin_balance = <Balances<T>>::get(&origin_account);
 			let target = T::Lookup::lookup(target)?;
-			ensure!(!amount.is_zero(), "transfer amount should be non-zero");
-			ensure!(origin_balance >= amount, "origin account balance must be greater than or equal to the transfer amount");
+			ensure!(!amount.is_zero(), Error::AmountZero);
+			ensure!(origin_balance >= amount, Error::BalanceLow);
 
 			Self::deposit_event(RawEvent::Transferred(id, origin, target.clone(), amount));
 			<Balances<T>>::insert(origin_account, origin_balance - amount);
@@ -185,9 +189,9 @@ decl_module! {
 
 		/// Destroy any assets of `id` owned by `origin`.
 		fn destroy(origin, #[compact] id: T::AssetId) {
-			let origin = ensure_signed(origin)?;
+			let origin = ensure_signed(origin).map_err(|e| e.as_str())?;
 			let balance = <Balances<T>>::take((id, &origin));
-			ensure!(!balance.is_zero(), "origin balance should be non-zero");
+			ensure!(!balance.is_zero(), Error::BalanceZero);
 
 			<TotalSupply<T>>::mutate(id, |total_supply| *total_supply -= balance);
 			Self::deposit_event(RawEvent::Destroyed(id, origin, balance));
@@ -195,7 +199,7 @@ decl_module! {
 	}
 }
 
-decl_event!(
+decl_event! {
 	pub enum Event<T> where
 		<T as frame_system::Trait>::AccountId,
 		<T as Trait>::Balance,
@@ -208,7 +212,19 @@ decl_event!(
 		/// Some assets were destroyed.
 		Destroyed(AssetId, AccountId, Balance),
 	}
-);
+}
+
+decl_error! {
+	pub enum Error {
+		/// Transfer amount should be non-zero
+		AmountZero,
+		/// Account balance must be greater than or equal to the transfer amount
+		BalanceLow,
+		/// Balance should be non-zero
+		BalanceZero,
+	}
+
+}
 
 decl_storage! {
 	trait Store for Module<T: Trait> as Assets {
@@ -337,7 +353,7 @@ mod tests {
 			assert_eq!(Assets::balance(0, 2), 50);
 			assert_ok!(Assets::destroy(Origin::signed(1), 0));
 			assert_eq!(Assets::balance(0, 1), 0);
-			assert_noop!(Assets::transfer(Origin::signed(1), 0, 1, 50), "origin account balance must be greater than or equal to the transfer amount");
+			assert_noop!(Assets::transfer(Origin::signed(1), 0, 1, 50), Error::BalanceLow);
 		});
 	}
 
@@ -346,7 +362,7 @@ mod tests {
 		new_test_ext().execute_with(|| {
 			assert_ok!(Assets::issue(Origin::signed(1), 100));
 			assert_eq!(Assets::balance(0, 1), 100);
-			assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 0), "transfer amount should be non-zero");
+			assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 0), Error::AmountZero);
 		});
 	}
 
@@ -355,7 +371,7 @@ mod tests {
 		new_test_ext().execute_with(|| {
 			assert_ok!(Assets::issue(Origin::signed(1), 100));
 			assert_eq!(Assets::balance(0, 1), 100);
-			assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 101), "origin account balance must be greater than or equal to the transfer amount");
+			assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 101), Error::BalanceLow);
 		});
 	}
 
@@ -373,7 +389,7 @@ mod tests {
 		new_test_ext().execute_with(|| {
 			assert_ok!(Assets::issue(Origin::signed(1), 100));
 			assert_eq!(Assets::balance(0, 2), 0);
-			assert_noop!(Assets::destroy(Origin::signed(2), 0), "origin balance should be non-zero");
+			assert_noop!(Assets::destroy(Origin::signed(2), 0), Error::BalanceZero);
 		});
 	}
 }