Use decl_error in common runtime modules (#796)

* use decl_error in common runtime modules

* Apply suggestions from code review

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

polkadot/runtime/common/src/attestations.rs

@@ -21,7 +21,9 @@
 
 use rstd::prelude::*;
 use codec::{Encode, Decode};
-use frame_support::{decl_storage, decl_module, ensure, dispatch::DispatchResult, traits::Get};
+use frame_support::{
+	decl_storage, decl_module, decl_error, ensure, dispatch::DispatchResult, traits::Get
+};
 
 use primitives::{Hash, parachain::{AttestedCandidate, CandidateReceipt, Id as ParaId}};
 use sp_runtime::RuntimeDebug;
@@ -106,13 +108,22 @@ decl_storage! {
 	}
 }
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// More attestations can be added only once in a block.
+		TooManyAttestations,
+	}
+}
+
 decl_module! {
 	/// Parachain-attestations module.
 	pub struct Module<T: Trait> for enum Call where origin: <T as system::Trait>::Origin {
+		type Error = Error<T>;
+
 		/// Provide candidate receipts for parachains, in ascending order by id.
 		fn more_attestations(origin, _more: MoreAttestations) -> DispatchResult {
 			ensure_none(origin)?;
-			ensure!(!<DidUpdate>::exists(), "More attestations can be added only once in a block.");
+			ensure!(!<DidUpdate>::exists(), Error::<T>::TooManyAttestations);
 			<DidUpdate>::put(true);
 
 			Ok(())

polkadot/runtime/common/src/claims.rs

@@ -18,7 +18,7 @@
 
 use rstd::prelude::*;
 use sp_io::{hashing::keccak_256, crypto::secp256k1_ecdsa_recover};
-use frame_support::{decl_event, decl_storage, decl_module};
+use frame_support::{decl_event, decl_storage, decl_module, decl_error};
 use frame_support::weights::SimpleDispatchInfo;
 use frame_support::traits::{Currency, Get, VestingCurrency};
 use system::{ensure_root, ensure_none};
@@ -102,6 +102,15 @@ decl_event!(
 	}
 );
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// Invalid Ethereum signature.
+		InvalidEthereumSignature,
+		/// Ethereum address has no claim.
+		SignerHasNoClaim,
+	}
+}
+
 decl_storage! {
 	// A macro for the Storage trait, and its implementation, for this module.
 	// This allows for type-safe usage of the Substrate storage database, so you can
@@ -126,6 +135,8 @@ decl_storage! {
 
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		type Error = Error<T>;
+
 		/// The Prefix that is used in signed Ethereum messages for this network
 		const Prefix: &[u8] = T::Prefix::get();
 
@@ -139,10 +150,10 @@ decl_module! {
 
 			let data = dest.using_encoded(to_ascii_hex);
 			let signer = Self::eth_recover(&ethereum_signature, &data)
-				.ok_or("Invalid Ethereum signature")?;
+				.ok_or(Error::<T>::InvalidEthereumSignature)?;
 
 			let balance_due = <Claims<T>>::get(&signer)
-				.ok_or("Ethereum address has no claim")?;
+				.ok_or(Error::<T>::SignerHasNoClaim)?;
 
 			// Check if this claim should have a vesting schedule.
 			if let Some(vs) = <Vesting<T>>::get(&signer) {
@@ -415,7 +426,7 @@ mod tests {
 			assert_eq!(Balances::free_balance(&42), 0);
 			assert_noop!(
 				Claims::claim(Origin::NONE, 69, sig(&bob(), &69u64.encode())),
-				"Ethereum address has no claim"
+				Error::<Test>::SignerHasNoClaim
 			);
 			assert_ok!(Claims::mint_claim(Origin::ROOT, eth(&bob()), 200, None));
 			assert_ok!(Claims::claim(Origin::NONE, 69, sig(&bob(), &69u64.encode())));
@@ -434,7 +445,7 @@ mod tests {
 			assert_eq!(Balances::free_balance(&42), 0);
 			assert_noop!(
 				Claims::claim(Origin::NONE, 69, sig(&bob(), &69u64.encode())),
-				"Ethereum address has no claim"
+				Error::<Test>::SignerHasNoClaim
 			);
 			assert_ok!(Claims::mint_claim(Origin::ROOT, eth(&bob()), 200, Some((50, 10, 1))));
 			assert_ok!(Claims::claim(Origin::NONE, 69, sig(&bob(), &69u64.encode())));
@@ -459,7 +470,10 @@ mod tests {
 		new_test_ext().execute_with(|| {
 			assert_eq!(Balances::free_balance(&42), 0);
 			assert_ok!(Claims::claim(Origin::NONE, 42, sig(&alice(), &42u64.encode())));
-			assert_noop!(Claims::claim(Origin::NONE, 42, sig(&alice(), &42u64.encode())), "Ethereum address has no claim");
+			assert_noop!(
+				Claims::claim(Origin::NONE, 42, sig(&alice(), &42u64.encode())),
+				Error::<Test>::SignerHasNoClaim
+			);
 		});
 	}
 
@@ -467,7 +481,10 @@ mod tests {
 	fn non_sender_sig_doesnt_work() {
 		new_test_ext().execute_with(|| {
 			assert_eq!(Balances::free_balance(&42), 0);
-			assert_noop!(Claims::claim(Origin::NONE, 42, sig(&alice(), &69u64.encode())), "Ethereum address has no claim");
+			assert_noop!(
+				Claims::claim(Origin::NONE, 42, sig(&alice(), &69u64.encode())),
+				Error::<Test>::SignerHasNoClaim
+			);
 		});
 	}
 
@@ -475,7 +492,10 @@ mod tests {
 	fn non_claimant_doesnt_work() {
 		new_test_ext().execute_with(|| {
 			assert_eq!(Balances::free_balance(&42), 0);
-			assert_noop!(Claims::claim(Origin::NONE, 42, sig(&bob(), &69u64.encode())), "Ethereum address has no claim");
+			assert_noop!(
+				Claims::claim(Origin::NONE, 42, sig(&bob(), &69u64.encode())),
+				Error::<Test>::SignerHasNoClaim
+			);
 		});
 	}
 

polkadot/runtime/common/src/crowdfund.rs

@@ -67,7 +67,7 @@
 //! funds ultimately end up in module's fund sub-account.
 
 use frame_support::{
-	decl_module, decl_storage, decl_event, storage::child, ensure, traits::{
+	decl_module, decl_storage, decl_event, decl_error, storage::child, ensure, traits::{
 		Currency, Get, OnUnbalanced, WithdrawReason, ExistenceRequirement::AllowDeath
 	}
 };
@@ -187,8 +187,56 @@ decl_event! {
 	}
 }
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// Last slot must be greater than first slot.
+		LastSlotBeforeFirstSlot,
+		/// The last slot cannot be more then 3 slots after the first slot.
+		LastSlotTooFarInFuture,
+		/// The campaign ends before the current block number. The end must be in the future.
+		CannotEndInPast,
+		/// There was an overflow.
+		Overflow,
+		/// The contribution was below the minimum, `MinContribution`.
+		ContributionTooSmall,
+		/// Invalid fund index.
+		InvalidFundIndex,
+		/// Contributions exceed maximum amount.
+		CapExceeded,
+		/// The contribution period has already ended.
+		ContributionPeriodOver,
+		/// The origin of this call is invalid.
+		InvalidOrigin,
+		/// Deployment data for a fund can only be set once. The deployment data for this fund
+		/// already exists.
+		ExistingDeployData,
+		/// Deployment data has not been set for this fund.
+		UnsetDeployData,
+		/// This fund has already been onboarded.
+		AlreadyOnboard,
+		/// This crowdfund does not correspond to a parachain.
+		NotParachain,
+		/// This parachain still has its deposit. Implies that it has already been offboarded.
+		ParaHasDeposit,
+		/// Funds have not yet been returned.
+		FundsNotReturned,
+		/// Fund has not yet retired.
+		FundNotRetired,
+		/// The crowdfund has not yet ended.
+		FundNotEnded,
+		/// There are no contributions stored in this crowdfund.
+		NoContributions,
+		/// This crowdfund has an active parachain and cannot be dissolved.
+		HasActiveParachain,
+		/// The retirement period has not ended.
+		InRetirementPeriod,
+	}
+}
+
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		type Error = Error<T>;
+
 		fn deposit_event() = default;
 
 		/// Create a new crowdfunding campaign for a parachain slot deposit for the current auction.
@@ -201,16 +249,16 @@ decl_module! {
 		) {
 			let owner = ensure_signed(origin)?;
 
-			ensure!(first_slot < last_slot, "last slot must be greater than first slot");
-			ensure!(last_slot <= first_slot + 3.into(), "last slot cannot be more then 3 more than first slot");
-			ensure!(end > <system::Module<T>>::block_number(), "end must be in the future");
+			ensure!(first_slot < last_slot, Error::<T>::LastSlotBeforeFirstSlot);
+			ensure!(last_slot <= first_slot + 3.into(), Error::<T>::LastSlotTooFarInFuture);
+			ensure!(end > <system::Module<T>>::block_number(), Error::<T>::CannotEndInPast);
 
 			let deposit = T::SubmissionDeposit::get();
 			let transfer = WithdrawReason::Transfer.into();
 			let imb = T::Currency::withdraw(&owner, deposit, transfer, AllowDeath)?;
 
 			let index = FundCount::get();
-			let next_index = index.checked_add(1).ok_or("overflow when adding fund")?;
+			let next_index = index.checked_add(1).ok_or(Error::<T>::Overflow)?;
 			FundCount::put(next_index);
 
 			// No fees are paid here if we need to create this account; that's why we don't just
@@ -239,14 +287,14 @@ decl_module! {
 		fn contribute(origin, #[compact] index: FundIndex, #[compact] value: BalanceOf<T>) {
 			let who = ensure_signed(origin)?;
 
-			ensure!(value >= T::MinContribution::get(), "contribution too small");
-			let mut fund = Self::funds(index).ok_or("invalid fund index")?;
-			fund.raised  = fund.raised.checked_add(&value).ok_or("overflow when adding new funds")?;
-			ensure!(fund.raised <= fund.cap, "contributions exceed cap");
+			ensure!(value >= T::MinContribution::get(), Error::<T>::ContributionTooSmall);
+			let mut fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			fund.raised  = fund.raised.checked_add(&value).ok_or(Error::<T>::Overflow)?;
+			ensure!(fund.raised <= fund.cap, Error::<T>::CapExceeded);
 
 			// Make sure crowdfund has not ended
 			let now = <system::Module<T>>::block_number();
-			ensure!(fund.end > now, "contribution period ended");
+			ensure!(fund.end > now, Error::<T>::ContributionPeriodOver);
 
 			T::Currency::transfer(&who, &Self::fund_account_id(index), value, AllowDeath)?;
 
@@ -301,9 +349,9 @@ decl_module! {
 		) {
 			let who = ensure_signed(origin)?;
 
-			let mut fund = Self::funds(index).ok_or("invalid fund index")?;
-			ensure!(fund.owner == who, "origin must be fund owner");
-			ensure!(fund.deploy_data.is_none(), "deploy data already set");
+			let mut fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			ensure!(fund.owner == who, Error::<T>::InvalidOrigin); // must be fund owner
+			ensure!(fund.deploy_data.is_none(), Error::<T>::ExistingDeployData);
 
 			fund.deploy_data = Some((code_hash, initial_head_data));
 
@@ -324,9 +372,9 @@ decl_module! {
 		) {
 			let _ = ensure_signed(origin)?;
 
-			let mut fund = Self::funds(index).ok_or("invalid fund index")?;
-			let (code_hash, initial_head_data) = fund.clone().deploy_data.ok_or("deploy data not fixed")?;
-			ensure!(fund.parachain.is_none(), "fund already onboarded");
+			let mut fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			let (code_hash, initial_head_data) = fund.clone().deploy_data.ok_or(Error::<T>::UnsetDeployData)?;
+			ensure!(fund.parachain.is_none(), Error::<T>::AlreadyOnboard);
 			fund.parachain = Some(para_id);
 
 			let fund_origin = system::RawOrigin::Signed(Self::fund_account_id(index)).into();
@@ -341,13 +389,13 @@ decl_module! {
 		fn begin_retirement(origin, #[compact] index: FundIndex) {
 			let _ = ensure_signed(origin)?;
 
-			let mut fund = Self::funds(index).ok_or("invalid fund index")?;
-			let parachain_id = fund.parachain.take().ok_or("fund has no parachain")?;
+			let mut fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			let parachain_id = fund.parachain.take().ok_or(Error::<T>::NotParachain)?;
 			// No deposit information implies the parachain was off-boarded
-			ensure!(<slots::Module<T>>::deposits(parachain_id).len() == 0, "parachain still has deposit");
+			ensure!(<slots::Module<T>>::deposits(parachain_id).len() == 0, Error::<T>::ParaHasDeposit);
 			let account = Self::fund_account_id(index);
 			// Funds should be returned at the end of off-boarding
-			ensure!(T::Currency::free_balance(&account) >= fund.raised, "funds not yet returned");
+			ensure!(T::Currency::free_balance(&account) >= fund.raised, Error::<T>::FundsNotReturned);
 
 			// This fund just ended. Withdrawal period begins.
 			let now = <system::Module<T>>::block_number();
@@ -362,15 +410,15 @@ decl_module! {
 		fn withdraw(origin, #[compact] index: FundIndex) {
 			let who = ensure_signed(origin)?;
 
-			let mut fund = Self::funds(index).ok_or("invalid fund index")?;
-			ensure!(fund.parachain.is_none(), "fund has not retired");
+			let mut fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			ensure!(fund.parachain.is_none(), Error::<T>::FundNotRetired);
 			let now = <system::Module<T>>::block_number();
 
 			// `fund.end` can represent the end of a failed crowdsale or the beginning of retirement
-			ensure!(now >= fund.end, "fund has not ended");
+			ensure!(now >= fund.end, Error::<T>::FundNotEnded);
 
 			let balance = Self::contribution_get(index, &who);
-			ensure!(balance > Zero::zero(), "no contributions stored");
+			ensure!(balance > Zero::zero(), Error::<T>::NoContributions);
 
 			// Avoid using transfer to ensure we don't pay any fees.
 			let fund_account = &Self::fund_account_id(index);
@@ -392,12 +440,12 @@ decl_module! {
 		fn dissolve(origin, #[compact] index: FundIndex) {
 			let _ = ensure_signed(origin)?;
 
-			let fund = Self::funds(index).ok_or("invalid fund index")?;
-			ensure!(fund.parachain.is_none(), "cannot dissolve fund with active parachain");
+			let fund = Self::funds(index).ok_or(Error::<T>::InvalidFundIndex)?;
+			ensure!(fund.parachain.is_none(), Error::<T>::HasActiveParachain);
 			let now = <system::Module<T>>::block_number();
 			ensure!(
 				now >= fund.end.saturating_add(T::RetirementPeriod::get()),
-				"retirement period not over"
+				Error::<T>::InRetirementPeriod
 			);
 
 			let account = Self::fund_account_id(index);
@@ -673,6 +721,7 @@ mod tests {
 	type Crowdfund = Module<Test>;
 	type RandomnessCollectiveFlip = randomness_collective_flip::Module<Test>;
 	use balances::Error as BalancesError;
+	use slots::Error as SlotsError;
 
 	// This function basically just builds a genesis storage key/value store according to
 	// our desired mockup.
@@ -749,11 +798,20 @@ mod tests {
 	fn create_handles_basic_errors() {
 		new_test_ext().execute_with(|| {
 			// Cannot create a crowdfund with bad slots
-			assert_noop!(Crowdfund::create(Origin::signed(1), 1000, 4, 1, 9), "last slot must be greater than first slot");
-			assert_noop!(Crowdfund::create(Origin::signed(1), 1000, 1, 5, 9), "last slot cannot be more then 3 more than first slot");
+			assert_noop!(
+				Crowdfund::create(Origin::signed(1), 1000, 4, 1, 9),
+				Error::<Test>::LastSlotBeforeFirstSlot
+			);
+			assert_noop!(
+				Crowdfund::create(Origin::signed(1), 1000, 1, 5, 9),
+				Error::<Test>::LastSlotTooFarInFuture
+			);
 
 			// Cannot create a crowdfund without some deposit funds
-			assert_noop!(Crowdfund::create(Origin::signed(1337), 1000, 1, 3, 9), BalancesError::<Test, _>::InsufficientBalance);
+			assert_noop!(
+				Crowdfund::create(Origin::signed(1337), 1000, 1, 3, 9),
+				BalancesError::<Test, _>::InsufficientBalance
+			);
 		});
 	}
 
@@ -791,22 +849,22 @@ mod tests {
 	fn contribute_handles_basic_errors() {
 		new_test_ext().execute_with(|| {
 			// Cannot contribute to non-existing fund
-			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 49), "invalid fund index");
+			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 49), Error::<Test>::InvalidFundIndex);
 			// Cannot contribute below minimum contribution
-			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 9), "contribution too small");
+			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 9), Error::<Test>::ContributionTooSmall);
 
 			// Set up a crowdfund
 			assert_ok!(Crowdfund::create(Origin::signed(1), 1000, 1, 4, 9));
 			assert_ok!(Crowdfund::contribute(Origin::signed(1), 0, 101));
 
 			// Cannot contribute past the limit
-			assert_noop!(Crowdfund::contribute(Origin::signed(2), 0, 900), "contributions exceed cap");
+			assert_noop!(Crowdfund::contribute(Origin::signed(2), 0, 900), Error::<Test>::CapExceeded);
 
 			// Move past end date
 			run_to_block(10);
 
 			// Cannot contribute to ended fund
-			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 49), "contribution period ended");
+			assert_noop!(Crowdfund::contribute(Origin::signed(1), 0, 49), Error::<Test>::ContributionPeriodOver);
 		});
 	}
 
@@ -845,7 +903,7 @@ mod tests {
 				0,
 				<Test as system::Trait>::Hash::default(),
 				vec![0]),
-				"origin must be fund owner"
+				Error::<Test>::InvalidOrigin
 			);
 
 			// Cannot set deploy data to an invalid index
@@ -854,7 +912,7 @@ mod tests {
 				1,
 				<Test as system::Trait>::Hash::default(),
 				vec![0]),
-				"invalid fund index"
+				Error::<Test>::InvalidFundIndex
 			);
 
 			// Cannot set deploy data after it already has been set
@@ -870,7 +928,7 @@ mod tests {
 				0,
 				<Test as system::Trait>::Hash::default(),
 				vec![1]),
-				"deploy data already set"
+				Error::<Test>::ExistingDeployData
 			);
 		});
 	}
@@ -924,9 +982,9 @@ mod tests {
 			run_to_block(10);
 
 			// Cannot onboard invalid fund index
-			assert_noop!(Crowdfund::onboard(Origin::signed(1), 1, 0.into()), "invalid fund index");
+			assert_noop!(Crowdfund::onboard(Origin::signed(1), 1, 0.into()), Error::<Test>::InvalidFundIndex);
 			// Cannot onboard crowdfund without deploy data
-			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()), "deploy data not fixed");
+			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()), Error::<Test>::UnsetDeployData);
 
 			// Add deploy data
 			assert_ok!(Crowdfund::fix_deploy_data(
@@ -937,13 +995,13 @@ mod tests {
 			));
 
 			// Cannot onboard fund with incorrect parachain id
-			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 1.into()), "parachain id not in onboarding");
+			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 1.into()), SlotsError::<Test>::ParaNotOnboarding);
 
 			// Onboard crowdfund
 			assert_ok!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()));
 
 			// Cannot onboard fund again
-			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()), "fund already onboarded");
+			assert_noop!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()), Error::<Test>::AlreadyOnboard);
 		});
 	}
 
@@ -1011,7 +1069,7 @@ mod tests {
 			run_to_block(10);
 
 			// Cannot retire fund that is not onboarded
-			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), "fund has no parachain");
+			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), Error::<Test>::NotParachain);
 
 			// Onboard crowdfund
 			assert_ok!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()));
@@ -1020,16 +1078,16 @@ mod tests {
 			assert_eq!(fund.parachain, Some(0.into()));
 
 			// Cannot retire fund whose deposit has not been returned
-			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), "parachain still has deposit");
+			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), Error::<Test>::ParaHasDeposit);
 
 			run_to_block(50);
 
 			// Cannot retire invalid fund index
-			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 1), "invalid fund index");
+			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 1), Error::<Test>::InvalidFundIndex);
 
 			// Cannot retire twice
 			assert_ok!(Crowdfund::begin_retirement(Origin::signed(1), 0));
-			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), "fund has no parachain");
+			assert_noop!(Crowdfund::begin_retirement(Origin::signed(1), 0), Error::<Test>::NotParachain);
 		});
 	}
 
@@ -1072,14 +1130,14 @@ mod tests {
 			run_to_block(5);
 
 			// Cannot withdraw before fund ends
-			assert_noop!(Crowdfund::withdraw(Origin::signed(1), 0), "fund has not ended");
+			assert_noop!(Crowdfund::withdraw(Origin::signed(1), 0), Error::<Test>::FundNotEnded);
 
 			run_to_block(10);
 
 			// Cannot withdraw if they did not contribute
-			assert_noop!(Crowdfund::withdraw(Origin::signed(2), 0), "no contributions stored");
+			assert_noop!(Crowdfund::withdraw(Origin::signed(2), 0), Error::<Test>::NoContributions);
 			// Cannot withdraw from a non-existent fund
-			assert_noop!(Crowdfund::withdraw(Origin::signed(1), 1), "invalid fund index");
+			assert_noop!(Crowdfund::withdraw(Origin::signed(1), 1), Error::<Test>::InvalidFundIndex);
 		});
 	}
 
@@ -1130,9 +1188,9 @@ mod tests {
 			assert_ok!(Crowdfund::contribute(Origin::signed(3), 0, 300));
 
 			// Cannot dissolve an invalid fund index
-			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 1), "invalid fund index");
+			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 1), Error::<Test>::InvalidFundIndex);
 			// Cannot dissolve a fund in progress
-			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 0), "retirement period not over");
+			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 0), Error::<Test>::InRetirementPeriod);
 
 			run_to_block(10);
 
@@ -1146,7 +1204,7 @@ mod tests {
 			assert_ok!(Crowdfund::onboard(Origin::signed(1), 0, 0.into()));
 
 			// Cannot dissolve an active fund
-			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 0), "cannot dissolve fund with active parachain");
+			assert_noop!(Crowdfund::dissolve(Origin::signed(1), 0), Error::<Test>::HasActiveParachain);
 		});
 	}
 

polkadot/runtime/common/src/parachains.rs

@@ -35,7 +35,7 @@ use primitives::{
 	},
 };
 use frame_support::{
-	Parameter, dispatch::DispatchResult, decl_storage, decl_module, ensure,
+	Parameter, dispatch::DispatchResult, decl_storage, decl_module, decl_error, ensure,
 	traits::{Currency, Get, WithdrawReason, ExistenceRequirement, Randomness},
 };
 
@@ -182,10 +182,10 @@ decl_storage! {
 		/// The ordered list of ParaIds that have a `RelayDispatchQueue` entry.
 		NeedsDispatch: Vec<ParaId>;
 
-		/// Some if the parachain heads get updated in this block, along with the parachain IDs that
-		/// did update. Ordered in the same way as `registrar::Active` (i.e. by ParaId).
+		/// `Some` if the parachain heads get updated in this block, along with the parachain IDs
+		/// that did update. Ordered in the same way as `registrar::Active` (i.e. by ParaId).
 		///
-		/// None if not yet updated.
+		/// `None` if not yet updated.
 		pub DidUpdate: Option<Vec<ParaId>>;
 	}
 	add_extra_genesis {
@@ -194,19 +194,60 @@ decl_storage! {
 	}
 }
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// Parachain heads must be updated only once in the block.
+		TooManyHeadUpdates,
+		/// Too many parachain candidates.
+		TooManyParaCandidates,
+		/// Proposed heads must be ascending order by parachain ID without duplicate.
+		HeadsOutOfOrder,
+		/// Candidate is for an unregistered parachain.
+		UnregisteredPara,
+		/// Invalid collator.
+		InvalidCollator,
+		/// The message queue is full. Messages will be added when there is space.
+		QueueFull,
+		/// The message origin is invalid.
+		InvalidMessageOrigin,
+		/// Egress routes should be in ascending order by parachain ID without duplicates.
+		EgressOutOfOrder,
+		/// A parachain cannot route a message to itself.
+		SelfAddressed,
+		/// The trie root cannot be empty.
+		EmptyTrieRoot,
+		/// Cannot route to a non-existing parachain.
+		DestinationDoesNotExist,
+		/// No validator group for parachain.
+		NoValidatorGroup,
+		/// Not enough validity votes for candidate.
+		NotEnoughValidityVotes,
+		/// The number of attestations exceeds the number of authorities.
+		VotesExceedsAuthorities,
+		/// Attesting validator not on this chain's validation duty.
+		WrongValidatorAttesting,
+		/// Invalid signature from attester.
+		InvalidSignature,
+		/// Extra untagged validity votes along with candidate.
+		UntaggedVotes,
+	}
+}
+
 decl_module! {
 	/// Parachains module.
 	pub struct Module<T: Trait> for enum Call where origin: <T as system::Trait>::Origin {
+		type Error = Error<T>;
+
 		/// Provide candidate receipts for parachains, in ascending order by id.
 		#[weight = SimpleDispatchInfo::FixedNormal(1_000_000)]
 		pub fn set_heads(origin, heads: Vec<AttestedCandidate>) -> DispatchResult {
 			ensure_none(origin)?;
-			ensure!(!<DidUpdate>::exists(), "Parachain heads must be updated only once in the block");
+			ensure!(!<DidUpdate>::exists(), Error::<T>::TooManyHeadUpdates);
 
 			let active_parachains = Self::active_parachains();
 
 			let parachain_count = active_parachains.len();
-			ensure!(heads.len() <= parachain_count, "Too many parachain candidates");
+			ensure!(heads.len() <= parachain_count, Error::<T>::TooManyParaCandidates);
 
 			let mut proceeded = Vec::with_capacity(heads.len());
 
@@ -221,15 +262,15 @@ decl_module! {
 						// proposed heads must be ascending order by parachain ID without duplicate.
 						ensure!(
 							last_id.as_ref().map_or(true, |x| x < &id),
-							"candidate out of order"
+							Error::<T>::HeadsOutOfOrder
 						);
 
 						// must be unknown since active parachains are always sorted.
 						let (_, maybe_required_collator) = iter.find(|para| para.0 == id)
-							.ok_or("candidate for unregistered parachain {}")?;
+							.ok_or(Error::<T>::UnregisteredPara)?;
 
 						if let Some((required_collator, _)) = maybe_required_collator {
-							ensure!(required_collator == &head.candidate.collator, "invalid collator");
+							ensure!(required_collator == &head.candidate.collator, Error::<T>::InvalidCollator);
 						}
 
 						Self::check_upward_messages(
@@ -371,11 +412,11 @@ impl<T: Trait> Module<T> {
 						.fold(size as usize, |a, x| a + x.data.len())
 					<= watermark_queue_size
 				),
-				"Messages added when queue full"
+				Error::<T>::QueueFull
 			);
 			if !id.is_system() {
 				for m in upward_messages.iter() {
-					ensure!(m.origin != ParachainDispatchOrigin::Root, "bad message origin");
+					ensure!(m.origin != ParachainDispatchOrigin::Root, Error::<T>::InvalidMessageOrigin);
 				}
 			}
 		}
@@ -625,25 +666,25 @@ impl<T: Trait> Module<T> {
 			// egress routes should be ascending order by parachain ID without duplicate.
 			ensure!(
 				last_egress_id.as_ref().map_or(true, |x| x < &egress_para_id),
-				"Egress routes out of order by ID",
+				Error::<T>::EgressOutOfOrder,
 			);
 
 			// a parachain can't route to self
 			ensure!(
 				*egress_para_id != head.candidate.parachain_index,
-				"Parachain routing to self",
+				Error::<T>::SelfAddressed,
 			);
 
 			// no empty trie roots
 			ensure!(
 				*root != EMPTY_TRIE_ROOT.into(),
-				"Empty trie root included",
+				Error::<T>::EmptyTrieRoot,
 			);
 
 			// can't route to a parachain which doesn't exist
 			ensure!(
 				iter.find(|x| x == egress_para_id).is_some(),
-				"Routing to non-existent parachain",
+				Error::<T>::DestinationDoesNotExist,
 			);
 
 			last_egress_id = Some(egress_para_id)
@@ -737,16 +778,16 @@ impl<T: Trait> Module<T> {
 		for candidate in attested_candidates {
 			let para_id = candidate.parachain_index();
 			let validator_group = validator_groups.group_for(para_id)
-				.ok_or("no validator group for parachain")?;
+				.ok_or(Error::<T>::NoValidatorGroup)?;
 
 			ensure!(
 				candidate.validity_votes.len() >= majority_of(validator_group.len()),
-				"Not enough validity attestations",
+				Error::<T>::NotEnoughValidityVotes,
 			);
 
 			ensure!(
 				candidate.validity_votes.len() <= authorities.len(),
-				"The number of attestations exceeds the number of authorities",
+				Error::<T>::VotesExceedsAuthorities,
 			);
 
 			let fees = candidate.candidate().fees;
@@ -764,7 +805,7 @@ impl<T: Trait> Module<T> {
 				.enumerate()
 			{
 				let validity_attestation = match candidate.validity_votes.get(vote_index) {
-					None => Err("Not enough validity votes")?,
+					None => Err(Error::<T>::NotEnoughValidityVotes)?,
 					Some(v) => {
 						expected_votes_len = vote_index + 1;
 						v
@@ -772,7 +813,7 @@ impl<T: Trait> Module<T> {
 				};
 
 				if validator_group.iter().find(|&(idx, _)| *idx == auth_index).is_none() {
-					Err("Attesting validator not on this chain's validation duty.")?
+					Err(Error::<T>::WrongValidatorAttesting)?
 				}
 
 				let (payload, sig) = match validity_attestation {
@@ -798,7 +839,7 @@ impl<T: Trait> Module<T> {
 
 				ensure!(
 					sig.verify(&payload[..], &authorities[auth_index]),
-					"Candidate validity attestation signature is bad.",
+					Error::<T>::InvalidSignature,
 				);
 			}
 
@@ -806,7 +847,7 @@ impl<T: Trait> Module<T> {
 
 			ensure!(
 				candidate.validity_votes.len() == expected_votes_len,
-				"Extra untagged validity votes along with candidate",
+				Error::<T>::UntaggedVotes
 			);
 		}
 
@@ -915,7 +956,7 @@ mod tests {
 	};
 	use keyring::Sr25519Keyring;
 	use frame_support::{
-		impl_outer_origin, impl_outer_dispatch, assert_ok, assert_err, parameter_types,
+		impl_outer_origin, impl_outer_dispatch, assert_ok, assert_err, assert_noop, parameter_types,
 	};
 	use crate::parachains;
 	use crate::registrar;
@@ -1447,7 +1488,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full"
+				Error::<Test>::QueueFull
 			);
 
 			// too many messages.
@@ -1458,7 +1499,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full"
+				Error::<Test>::QueueFull
 			);
 		});
 	}
@@ -1480,7 +1521,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full"
+				Error::<Test>::QueueFull
 			);
 		});
 	}
@@ -1501,7 +1542,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full"
+				Error::<Test>::QueueFull
 			);
 		});
 	}
@@ -1522,7 +1563,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full",
+				Error::<Test>::QueueFull
 			);
 		});
 	}
@@ -1543,7 +1584,7 @@ mod tests {
 			];
 			assert_err!(
 				Parachains::check_upward_messages(0.into(), &messages, 2, 3),
-				"Messages added when queue full",
+				Error::<Test>::QueueFull
 			);
 		});
 	}
@@ -1968,12 +2009,10 @@ mod tests {
 
 			make_attestations(&mut candidate);
 
-			let result = Parachains::dispatch(
-				set_heads(vec![candidate.clone()]),
-				Origin::NONE,
+			assert_noop!(
+				Parachains::set_heads(Origin::NONE, vec![candidate.clone()]),
+				Error::<Test>::DestinationDoesNotExist
 			);
-
-			assert_eq!(Err("Routing to non-existent parachain".into()), result);
 		});
 	}
 
@@ -1993,12 +2032,10 @@ mod tests {
 
 			make_attestations(&mut candidate);
 
-			let result = Parachains::dispatch(
-				set_heads(vec![candidate.clone()]),
-				Origin::NONE,
+			assert_noop!(
+				Parachains::set_heads(Origin::NONE, vec![candidate.clone()]),
+				Error::<Test>::SelfAddressed
 			);
-
-			assert_eq!(Err("Parachain routing to self".into()), result);
 		});
 	}
 
@@ -2018,12 +2055,10 @@ mod tests {
 
 			make_attestations(&mut candidate);
 
-			let result = Parachains::dispatch(
-				set_heads(vec![candidate.clone()]),
-				Origin::NONE,
+			assert_noop!(
+				Parachains::set_heads(Origin::NONE, vec![candidate.clone()]),
+				Error::<Test>::EgressOutOfOrder
 			);
-
-			assert_eq!(Err("Egress routes out of order by ID".into()), result);
 		});
 	}
 
@@ -2043,12 +2078,10 @@ mod tests {
 
 			make_attestations(&mut candidate);
 
-			let result = Parachains::dispatch(
-				set_heads(vec![candidate.clone()]),
-				Origin::NONE,
+			assert_noop!(
+				Parachains::set_heads(Origin::NONE, vec![candidate.clone()]),
+				Error::<Test>::EmptyTrieRoot
 			);
-
-			assert_eq!(Err("Empty trie root included".into()), result);
 		});
 	}
 

polkadot/runtime/common/src/registrar.rs

@@ -29,7 +29,7 @@ use sp_runtime::{
 };
 
 use frame_support::{
-	decl_storage, decl_module, decl_event, ensure,
+	decl_storage, decl_module, decl_event, decl_error, ensure,
 	dispatch::{DispatchResult, IsSubType}, traits::{Get, Currency, ReservableCurrency},
 	weights::{SimpleDispatchInfo, DispatchInfo},
 };
@@ -70,11 +70,11 @@ impl<T: Trait> Registrar<T::AccountId> for Module<T> {
 		code: Vec<u8>,
 		initial_head_data: Vec<u8>,
 	) -> DispatchResult {
-		ensure!(!Paras::exists(id), "Parachain already exists");
+		ensure!(!Paras::exists(id), Error::<T>::ParaAlreadyExists);
 		if let Scheduling::Always = info.scheduling {
 			Parachains::mutate(|parachains|
 				match parachains.binary_search(&id) {
-					Ok(_) => Err("Parachain already exists"),
+					Ok(_) => Err(Error::<T>::ParaAlreadyExists),
 					Err(idx) => {
 						parachains.insert(idx, id);
 						Ok(())
@@ -88,12 +88,12 @@ impl<T: Trait> Registrar<T::AccountId> for Module<T> {
 	}
 
 	fn deregister_para(id: ParaId) -> DispatchResult {
-		let info = Paras::take(id).ok_or("Invalid id")?;
+		let info = Paras::take(id).ok_or(Error::<T>::InvalidChainId)?;
 		if let Scheduling::Always = info.scheduling {
 			Parachains::mutate(|parachains|
 				parachains.binary_search(&id)
 					.map(|index| parachains.remove(index))
-					.map_err(|_| "Invalid id")
+					.map_err(|_| Error::<T>::InvalidChainId)
 			)?;
 		}
 		<parachains::Module<T>>::cleanup_para(id);
@@ -214,9 +214,22 @@ pub fn swap_ordered_existence<T: PartialOrd + Ord + Copy>(ids: &mut [T], one: T,
 	ids.sort();
 }
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// Parachain already exists.
+		ParaAlreadyExists,
+		/// Invalid parachain ID.
+		InvalidChainId,
+		/// Invalid parathread ID.
+		InvalidThreadId,
+	}
+}
+
 decl_module! {
 	/// Parachains module.
 	pub struct Module<T: Trait> for enum Call where origin: <T as system::Trait>::Origin {
+		type Error = Error<T>;
+
 		fn deposit_event() = default;
 
 		/// Register a parachain with given code.
@@ -299,8 +312,8 @@ decl_module! {
 		fn deregister_parathread(origin) {
 			let id = parachains::ensure_parachain(<T as Trait>::Origin::from(origin))?;
 
-			let info = Paras::get(id).ok_or("invalid id")?;
-			if let Scheduling::Dynamic = info.scheduling {} else { Err("invalid parathread id")? }
+			let info = Paras::get(id).ok_or(Error::<T>::InvalidChainId)?;
+			if let Scheduling::Dynamic = info.scheduling {} else { Err(Error::<T>::InvalidThreadId)? }
 
 			<Self as Registrar<T::AccountId>>::deregister_para(id)?;
 			Self::force_unschedule(|i| i == id);
@@ -494,7 +507,7 @@ impl<T: Trait + Send + Sync> rstd::fmt::Debug for LimitParathreadCommits<T> wher
 
 /// Custom validity errors used in Polkadot while validating transactions.
 #[repr(u8)]
-pub enum Error {
+pub enum ValidityError {
 	/// Parathread ID has already been submitted for this block.
 	Duplicate = 0,
 	/// Parathread ID does not identify a parathread.
@@ -527,7 +540,7 @@ impl<T: Trait + Send + Sync> SignedExtension for LimitParathreadCommits<T> where
 		if let Some(local_call) = call.is_sub_type() {
 			if let Call::select_parathread(id, collator, hash) = local_call {
 				// ensure that the para ID is actually a parathread.
-				let e = TransactionValidityError::from(InvalidTransaction::Custom(Error::InvalidId as u8));
+				let e = TransactionValidityError::from(InvalidTransaction::Custom(ValidityError::InvalidId as u8));
 				<Module<T>>::ensure_thread_id(*id).ok_or(e)?;
 
 				// ensure that we haven't already had a full complement of selected parathreads.
@@ -544,14 +557,14 @@ impl<T: Trait + Send + Sync> SignedExtension for LimitParathreadCommits<T> where
 				);
 
 				// ensure that this is not selecting a duplicate parathread ID
-				let e = TransactionValidityError::from(InvalidTransaction::Custom(Error::Duplicate as u8));
+				let e = TransactionValidityError::from(InvalidTransaction::Custom(ValidityError::Duplicate as u8));
 				let pos = selected_threads
 					.binary_search_by(|&(ref other_id, _)| other_id.cmp(id))
 					.err()
 					.ok_or(e)?;
 
 				// ensure that this is a live bid (i.e. that the thread's chain head matches)
-				let e = TransactionValidityError::from(InvalidTransaction::Custom(Error::InvalidId as u8));
+				let e = TransactionValidityError::from(InvalidTransaction::Custom(ValidityError::InvalidId as u8));
 				let head = <parachains::Module<T>>::parachain_head(id).ok_or(e)?;
 				let actual = T::Hashing::hash(&head);
 				ensure!(&actual == hash, InvalidTransaction::Stale);

polkadot/runtime/common/src/slots.rs

@@ -25,7 +25,7 @@ use sp_runtime::traits::{
 use frame_support::weights::SimpleDispatchInfo;
 use codec::{Encode, Decode, Codec};
 use frame_support::{
-	decl_module, decl_storage, decl_event, ensure, dispatch::DispatchResult,
+	decl_module, decl_storage, decl_event, decl_error, ensure, dispatch::DispatchResult,
 	traits::{Currency, ReservableCurrency, WithdrawReason, ExistenceRequirement, Get, Randomness},
 };
 use primitives::parachain::{
@@ -224,8 +224,37 @@ decl_event!(
 	}
 );
 
+decl_error! {
+	pub enum Error for Module<T: Trait> {
+		/// This auction is already in progress.
+		AuctionInProgress,
+		/// The lease period is in the past.
+		LeasePeriodInPast,
+		/// The origin for this call must be a parachain.
+		NotParaOrigin,
+		/// The parachain ID is not onboarding.
+		ParaNotOnboarding,
+		/// The origin for this call must be the origin who registered the parachain.
+		InvalidOrigin,
+		/// Parachain is already registered.
+		AlreadyRegistered,
+		/// The code must correspond to the hash.
+		InvalidCode,
+		/// Deployment data has not been set for this parachain.
+		UnsetDeployData,
+		/// The bid must overlap all intersecting ranges.
+		NonIntersectingRange,
+		/// Not a current auction.
+		NotCurrentAuction,
+		/// Not an auction.
+		NotAuction,
+	}
+}
+
 decl_module! {
 	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
+		type Error = Error<T>;
+
 		fn deposit_event() = default;
 
 		fn on_initialize(n: T::BlockNumber) {
@@ -274,8 +303,8 @@ decl_module! {
 			#[compact] lease_period_index: LeasePeriodOf<T>
 		) {
 			ensure_root(origin)?;
-			ensure!(!Self::is_in_progress(), "auction already in progress");
-			ensure!(lease_period_index >= Self::lease_period_index(), "lease period in past");
+			ensure!(!Self::is_in_progress(), Error::<T>::AuctionInProgress);
+			ensure!(lease_period_index >= Self::lease_period_index(), Error::<T>::LeasePeriodInPast);
 
 			// Bump the counter.
 			let n = <AuctionCounter>::mutate(|n| { *n += 1; *n });
@@ -340,7 +369,7 @@ decl_module! {
 		) {
 			let who = ensure_signed(origin)?;
 			let para_id = <ParaId>::try_from_account(&who)
-				.ok_or("account is not a parachain")?;
+				.ok_or(Error::<T>::NotParaOrigin)?;
 			let bidder = Bidder::Existing(para_id);
 			Self::handle_bid(bidder, auction_index, first_slot, last_slot, amount)?;
 		}
@@ -355,7 +384,7 @@ decl_module! {
 			let who = ensure_signed(origin)?;
 			let dest = T::Lookup::lookup(dest)?;
 			let para_id = <ParaId>::try_from_account(&who)
-				.ok_or("not a parachain origin")?;
+				.ok_or(Error::<T>::NotParaOrigin)?;
 			<Offboarding<T>>::insert(para_id, dest);
 		}
 
@@ -375,11 +404,11 @@ decl_module! {
 		) {
 			let who = ensure_signed(origin)?;
 			let (starts, details) = <Onboarding<T>>::get(&para_id)
-				.ok_or("parachain id not in onboarding")?;
+				.ok_or(Error::<T>::ParaNotOnboarding)?;
 			if let IncomingParachain::Unset(ref nb) = details {
-				ensure!(nb.who == who && nb.sub == sub, "parachain not registered by origin");
+				ensure!(nb.who == who && nb.sub == sub, Error::<T>::InvalidOrigin);
 			} else {
-				Err("already registered")?
+				Err(Error::<T>::AlreadyRegistered)?
 			}
 			let item = (starts, IncomingParachain::Fixed{code_hash, initial_head_data});
 			<Onboarding<T>>::insert(&para_id, item);
@@ -400,9 +429,9 @@ decl_module! {
 		#[weight = SimpleDispatchInfo::FixedNormal(5_000_000)]
 		pub fn elaborate_deploy_data(_origin, #[compact] para_id: ParaId, code: Vec<u8>) -> DispatchResult {
 			let (starts, details) = <Onboarding<T>>::get(&para_id)
-				.ok_or("parachain id not in onboarding")?;
+				.ok_or(Error::<T>::ParaNotOnboarding)?;
 			if let IncomingParachain::Fixed{code_hash, initial_head_data} = details {
-				ensure!(<T as system::Trait>::Hashing::hash(&code) == code_hash, "code not doesn't correspond to hash");
+				ensure!(<T as system::Trait>::Hashing::hash(&code) == code_hash, Error::<T>::InvalidCode);
 				if starts > Self::lease_period_index() {
 					// Hasn't yet begun. Replace the on-boarding entry with the new information.
 					let item = (starts, IncomingParachain::Deploy{code, initial_head_data});
@@ -417,7 +446,7 @@ decl_module! {
 
 				Ok(())
 			} else {
-				Err("deploy data not yet fixed".into())
+				Err(Error::<T>::UnsetDeployData)?
 			}
 		}
 	}
@@ -684,9 +713,9 @@ impl<T: Trait> Module<T> {
 		amount: BalanceOf<T>
 	) -> DispatchResult {
 		// Bidding on latest auction.
-		ensure!(auction_index == <AuctionCounter>::get(), "not current auction");
+		ensure!(auction_index == <AuctionCounter>::get(), Error::<T>::NotCurrentAuction);
 		// Assume it's actually an auction (this should never fail because of above).
-		let (first_lease_period, _) = <AuctionInfo<T>>::get().ok_or("not an auction")?;
+		let (first_lease_period, _) = <AuctionInfo<T>>::get().ok_or(Error::<T>::NotAuction)?;
 
 		// Our range.
 		let range = SlotRange::new_bounded(first_lease_period, first_slot, last_slot)?;
@@ -708,7 +737,7 @@ impl<T: Trait> Module<T> {
 						.expect("array has SLOT_RANGE_COUNT items; index never reaches that value; qed")
 					)
 				)),
-				"bidder winning non-intersecting range",
+				Error::<T>::NonIntersectingRange,
 			);
 
 			// Ok; we are the new winner of this range - reserve the additional amount and record.
@@ -1205,7 +1234,7 @@ mod tests {
 			assert_ok!(Slots::bid(Origin::signed(1), 0, 1, 2, 2, 1));
 			assert_noop!(
 				Slots::bid(Origin::signed(1), 0, 1, 3, 3, 1),
-				"bidder winning non-intersecting range"
+				Error::<Test>::NonIntersectingRange
 			);
 		});
 	}