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/collective/src/lib.rs

@@ -26,12 +26,12 @@
 use sp_std::{prelude::*, result};
 use sp_core::u32_trait::Value as U32;
 use sp_runtime::RuntimeDebug;
-use sp_runtime::traits::{Hash, EnsureOrigin};
+use sp_runtime::traits::{Hash, EnsureOrigin, ModuleDispatchError};
 use frame_support::weights::SimpleDispatchInfo;
 use frame_support::{
 	dispatch::{Dispatchable, Parameter}, codec::{Encode, Decode},
 	traits::{ChangeMembers, InitializeMembers}, decl_module, decl_event,
-	decl_storage, ensure,
+	decl_storage, decl_error, ensure,
 };
 use frame_system::{self as system, ensure_signed, ensure_root};
 
@@ -102,7 +102,7 @@ decl_storage! {
 	}
 }
 
-decl_event!(
+decl_event! {
 	pub enum Event<T, I=DefaultInstance> where
 		<T as frame_system::Trait>::Hash,
 		<T as frame_system::Trait>::AccountId,
@@ -122,13 +122,32 @@ decl_event!(
 		/// A single member did some action; `bool` is true if returned without error.
 		MemberExecuted(Hash, bool),
 	}
-);
+}
+
+decl_error! {
+	pub enum Error {
+		/// Account is not a member
+		NotMember,
+		/// Duplicate proposals not allowed
+		DuplicateProposal,
+		/// Proposal must exist
+		ProposalMissing,
+		/// Mismatched index
+		WrongIndex,
+		/// Duplicate vote ignored
+		DuplicateVote,
+		/// Members are already initialized!
+		AlreadyInitialized,
+	}
+}
 
 // Note: this module is not benchmarked. The weights are obtained based on the similarity of the
 // executed logic with other democracy function. Note that councillor operations are assigned to the
 // operational class.
 decl_module! {
 	pub struct Module<T: Trait<I>, I: Instance=DefaultInstance> for enum Call where origin: <T as frame_system::Trait>::Origin {
+		type Error = Error;
+
 		fn deposit_event() = default;
 
 		/// Set the collective's membership manually to `new_members`. Be nice to the chain and
@@ -137,7 +156,7 @@ decl_module! {
 		/// Requires root origin.
 		#[weight = SimpleDispatchInfo::FixedOperational(100_000)]
 		fn set_members(origin, new_members: Vec<T::AccountId>) {
-			ensure_root(origin)?;
+			ensure_root(origin).map_err(|e| e.as_str())?;
 			let mut new_members = new_members;
 			new_members.sort();
 			<Members<T, I>>::mutate(|m| {
@@ -151,8 +170,8 @@ decl_module! {
 		/// Origin must be a member of the collective.
 		#[weight = SimpleDispatchInfo::FixedOperational(100_000)]
 		fn execute(origin, proposal: Box<<T as Trait<I>>::Proposal>) {
-			let who = ensure_signed(origin)?;
-			ensure!(Self::is_member(&who), "proposer not a member");
+			let who = ensure_signed(origin).map_err(|e| e.as_str())?;
+			ensure!(Self::is_member(&who), Error::NotMember);
 
 			let proposal_hash = T::Hashing::hash_of(&proposal);
 			let ok = proposal.dispatch(RawOrigin::Member(who).into()).is_ok();
@@ -165,12 +184,12 @@ decl_module! {
 		/// # </weight>
 		#[weight = SimpleDispatchInfo::FixedOperational(5_000_000)]
 		fn propose(origin, #[compact] threshold: MemberCount, proposal: Box<<T as Trait<I>>::Proposal>) {
-			let who = ensure_signed(origin)?;
-			ensure!(Self::is_member(&who), "proposer not a member");
+			let who = ensure_signed(origin).map_err(|e| e.as_str())?;
+			ensure!(Self::is_member(&who), Error::NotMember);
 
 			let proposal_hash = T::Hashing::hash_of(&proposal);
 
-			ensure!(!<ProposalOf<T, I>>::exists(proposal_hash), "duplicate proposals not allowed");
+			ensure!(!<ProposalOf<T, I>>::exists(proposal_hash), Error::DuplicateProposal);
 
 			if threshold < 2 {
 				let seats = Self::members().len() as MemberCount;
@@ -194,11 +213,11 @@ decl_module! {
 		/// # </weight>
 		#[weight = SimpleDispatchInfo::FixedOperational(200_000)]
 		fn vote(origin, proposal: T::Hash, #[compact] index: ProposalIndex, approve: bool) {
-			let who = ensure_signed(origin)?;
-			ensure!(Self::is_member(&who), "voter not a member");
+			let who = ensure_signed(origin).map_err(|e| e.as_str())?;
+			ensure!(Self::is_member(&who), Error::NotMember);
 
-			let mut voting = Self::voting(&proposal).ok_or("proposal must exist")?;
-			ensure!(voting.index == index, "mismatched index");
+			let mut voting = Self::voting(&proposal).ok_or(Error::ProposalMissing)?;
+			ensure!(voting.index == index, Error::WrongIndex);
 
 			let position_yes = voting.ayes.iter().position(|a| a == &who);
 			let position_no = voting.nays.iter().position(|a| a == &who);
@@ -207,7 +226,7 @@ decl_module! {
 				if position_yes.is_none() {
 					voting.ayes.push(who.clone());
 				} else {
-					return Err("duplicate vote ignored")
+					return Err(Error::DuplicateVote)
 				}
 				if let Some(pos) = position_no {
 					voting.nays.swap_remove(pos);
@@ -216,7 +235,7 @@ decl_module! {
 				if position_no.is_none() {
 					voting.nays.push(who.clone());
 				} else {
-					return Err("duplicate vote ignored")
+					return Err(Error::DuplicateVote)
 				}
 				if let Some(pos) = position_yes {
 					voting.ayes.swap_remove(pos);
@@ -565,7 +584,7 @@ mod tests {
 			let proposal = make_proposal(42);
 			assert_noop!(
 				Collective::propose(Origin::signed(42), 3, Box::new(proposal.clone())),
-				"proposer not a member"
+				Error::NotMember
 			);
 		});
 	}
@@ -579,7 +598,7 @@ mod tests {
 			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
 			assert_noop!(
 				Collective::vote(Origin::signed(42), hash.clone(), 0, true),
-				"voter not a member",
+				Error::NotMember,
 			);
 		});
 	}
@@ -593,7 +612,7 @@ mod tests {
 			assert_ok!(Collective::propose(Origin::signed(1), 3, Box::new(proposal.clone())));
 			assert_noop!(
 				Collective::vote(Origin::signed(2), hash.clone(), 1, true),
-				"mismatched index",
+				Error::WrongIndex,
 			);
 		});
 	}
@@ -611,7 +630,7 @@ mod tests {
 			);
 			assert_noop!(
 				Collective::vote(Origin::signed(1), hash.clone(), 0, true),
-				"duplicate vote ignored",
+				Error::DuplicateVote,
 			);
 			assert_ok!(Collective::vote(Origin::signed(1), hash.clone(), 0, false));
 			assert_eq!(
@@ -620,7 +639,7 @@ mod tests {
 			);
 			assert_noop!(
 				Collective::vote(Origin::signed(1), hash.clone(), 0, false),
-				"duplicate vote ignored",
+				Error::DuplicateVote,
 			);
 
 			assert_eq!(System::events(), vec![