Fix: [Referenda Tracks] Resolve representation issues that are breaking PJS apps

cumulus/parachains/runtimes/collectives/collectives-westend/src/ambassador/tracks.rs

@@ -17,7 +17,8 @@
 
 use super::Origin;
 use crate::{Balance, BlockNumber, RuntimeOrigin, DAYS, DOLLARS, HOURS};
-use sp_runtime::{str_array as s, Perbill};
+use pallet_referenda::string_like_track_name as s;
+use sp_runtime::Perbill;
 use sp_std::borrow::Cow;
 
 /// Referendum `TrackId` type.

cumulus/parachains/runtimes/collectives/collectives-westend/src/fellowship/tracks.rs

@@ -18,7 +18,8 @@
 
 use crate::{Balance, BlockNumber, RuntimeOrigin, DAYS, DOLLARS, HOURS, MINUTES};
 use pallet_ranked_collective::Rank;
-use sp_runtime::{str_array as s, traits::Convert, Perbill};
+use pallet_referenda::string_like_track_name as s;
+use sp_runtime::{traits::Convert, Perbill};
 use sp_std::borrow::Cow;
 
 /// Referendum `TrackId` type.

polkadot/runtime/rococo/src/governance/fellowship.rs

@@ -18,11 +18,8 @@
 
 use alloc::borrow::Cow;
 use frame_support::traits::{MapSuccess, TryMapSuccess};
-use pallet_referenda::{Track, TrackInfo};
-use sp_runtime::{
-	str_array as s,
-	traits::{CheckedReduceBy, ConstU16, Replace, ReplaceWithDefault},
-};
+use pallet_referenda::{string_like_track_name as s, Track, TrackInfo};
+use sp_runtime::traits::{CheckedReduceBy, ConstU16, Replace, ReplaceWithDefault};
 
 use super::*;
 use crate::{CENTS, DAYS};

polkadot/runtime/rococo/src/governance/tracks.rs

@@ -19,7 +19,7 @@
 use super::*;
 
 use alloc::borrow::Cow;
-use sp_runtime::str_array as s;
+use pallet_referenda::string_like_track_name as s;
 
 const fn percent(x: i32) -> sp_arithmetic::FixedI64 {
 	sp_arithmetic::FixedI64::from_rational(x as u128, 100)

polkadot/runtime/westend/src/governance/tracks.rs

@@ -19,7 +19,7 @@
 use super::*;
 
 use alloc::borrow::Cow;
-use sp_runtime::str_array as s;
+use pallet_referenda::string_like_track_name as s;
 
 const fn percent(x: i32) -> sp_arithmetic::FixedI64 {
 	sp_arithmetic::FixedI64::from_rational(x as u128, 100)

prdoc/pr_7671.prdoc

@@ -0,0 +1,24 @@
+title: 'Fix: [Referenda Tracks] Resolve representation issues that are breaking PJS apps'
+
+doc:
+- audience: Runtime Dev
+  description: |-
+    The PR #2072 introduces a change in the representation of the `name` field, from a `&str` to a `[u8; N]` array. This is because 
+    tracks can be retrieves from storage, and thus, a static string representation doesn't meet with the storage traits requirements.
+
+    This PR encapsulates this array into a `StringLike` structure that allows representing the value as a `str` for SCALE and metadata
+    purposes. This is to avoid breaking changes.
+
+    This PR also reverts the representation of the `Tracks` constant as a tuple of `(TrackId, TrackInfo)` to accomplish the same
+    purpose of avoid breaking changes to runtime users and clients.
+crates:
+- name: pallet-referenda
+  bump: minor
+- name: collectives-westend-runtime
+  bump: minor
+- name: kitchensink-runtime
+  bump: minor
+- name: rococo-runtime
+  bump: minor
+- name: westend-runtime
+  bump: minor

substrate/bin/node/runtime/src/lib.rs

@@ -92,6 +92,7 @@ use sp_runtime::traits::TransactionExtension;
 // Can't use `FungibleAdapter` here until Treasury pallet migrates to fungibles
 // <https://github.com/paritytech/polkadot-sdk/issues/226>
 use pallet_broker::TaskId;
+use pallet_referenda::string_like_track_name as s;
 #[allow(deprecated)]
 pub use pallet_transaction_payment::{CurrencyAdapter, Multiplier, TargetedFeeAdjustment};
 use pallet_transaction_payment::{FeeDetails, RuntimeDispatchInfo};
@@ -107,7 +108,7 @@ use sp_core::{crypto::KeyTypeId, OpaqueMetadata, H160};
 use sp_inherents::{CheckInherentsResult, InherentData};
 use sp_runtime::{
 	curve::PiecewiseLinear,
-	generic, impl_opaque_keys, str_array as s,
+	generic, impl_opaque_keys,
 	traits::{
 		self, AccountIdConversion, BlakeTwo256, Block as BlockT, Bounded, ConvertInto,
 		MaybeConvert, NumberFor, OpaqueKeys, SaturatedConversion, StaticLookup,

substrate/frame/referenda/src/lib.rs

@@ -97,10 +97,11 @@ use self::branch::{BeginDecidingBranch, OneFewerDecidingBranch, ServiceBranch};
 pub use self::{
 	pallet::*,
 	types::{
-		BalanceOf, BlockNumberFor, BoundedCallOf, CallOf, Curve, DecidingStatus, DecidingStatusOf,
-		Deposit, InsertSorted, NegativeImbalanceOf, PalletsOriginOf, ReferendumIndex,
-		ReferendumInfo, ReferendumInfoOf, ReferendumStatus, ReferendumStatusOf, ScheduleAddressOf,
-		TallyOf, Track, TrackIdOf, TrackInfo, TrackInfoOf, TracksInfo, VotesOf,
+		string_like_track_name, BalanceOf, BlockNumberFor, BoundedCallOf, CallOf, Curve,
+		DecidingStatus, DecidingStatusOf, Deposit, InsertSorted, NegativeImbalanceOf,
+		PalletsOriginOf, ReferendumIndex, ReferendumInfo, ReferendumInfoOf, ReferendumStatus,
+		ReferendumStatusOf, ScheduleAddressOf, StringLike, TallyOf, Track, TrackIdOf, TrackInfo,
+		TrackInfoOf, TracksInfo, VotesOf,
 	},
 	weights::WeightInfo,
 };
@@ -225,8 +226,11 @@ pub mod pallet {
 	#[pallet::extra_constants]
 	impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		#[pallet::constant_name(Tracks)]
-		fn tracks() -> Vec<Track<TrackIdOf<T, I>, BalanceOf<T, I>, BlockNumberFor<T, I>>> {
-			T::Tracks::tracks().map(|t| t.into_owned()).collect()
+		fn tracks() -> Vec<(TrackIdOf<T, I>, TrackInfo<BalanceOf<T, I>, BlockNumberFor<T, I>>)> {
+			T::Tracks::tracks()
+				.map(|t| t.into_owned())
+				.map(|Track { id, info }| (id, info))
+				.collect()
 		}
 	}
 

substrate/frame/referenda/src/mock.rs

@@ -18,7 +18,7 @@
 //! The crate's tests.
 
 use super::*;
-use crate::{self as pallet_referenda, types::Track};
+use crate::{self as pallet_referenda, string_like_track_name as s, types::Track};
 use alloc::borrow::Cow;
 use codec::{Decode, DecodeWithMemTracking, Encode, MaxEncodedLen};
 use frame_support::{
@@ -30,7 +30,6 @@ use frame_support::{
 };
 use frame_system::{EnsureRoot, EnsureSignedBy};
 use sp_runtime::{
-	str_array as s,
 	traits::{BlakeTwo256, Hash},
 	BuildStorage, DispatchResult, Perbill,
 };

substrate/frame/referenda/src/types.rs

@@ -19,7 +19,7 @@
 
 use super::*;
 use alloc::borrow::Cow;
-use codec::{Decode, DecodeWithMemTracking, Encode, EncodeLike, MaxEncodedLen};
+use codec::{Compact, Decode, DecodeWithMemTracking, Encode, EncodeLike, MaxEncodedLen};
 use core::fmt::Debug;
 use frame_support::{
 	traits::{schedule::v3::Anon, Bounded},
@@ -118,13 +118,56 @@ pub struct Deposit<AccountId, Balance> {
 
 pub const DEFAULT_MAX_TRACK_NAME_LEN: usize = 25;
 
+#[inline]
+pub const fn string_like_track_name<const N: usize>(name: &str) -> StringLike<N> {
+	StringLike(sp_runtime::str_array(name))
+}
+
+#[derive(Clone, Eq, DecodeWithMemTracking, PartialEq, Debug)]
+pub struct StringLike<const N: usize>(pub [u8; N]);
+
+use codec::Input;
+use scale_info::Type;
+impl<const N: usize> TypeInfo for StringLike<N> {
+	type Identity = <&'static str as TypeInfo>::Identity;
+
+	fn type_info() -> Type {
+		<&str as TypeInfo>::type_info()
+	}
+}
+
+impl<const N: usize> MaxEncodedLen for StringLike<N> {
+	fn max_encoded_len() -> usize {
+		<Compact<u32> as MaxEncodedLen>::max_encoded_len().saturating_add(N)
+	}
+}
+
+impl<const N: usize> Encode for StringLike<N> {
+	fn encode(&self) -> Vec<u8> {
+		use codec::Compact;
+		(Compact(N as u32), self.0).encode()
+	}
+}
+
+impl<const N: usize> Decode for StringLike<N> {
+	fn decode<I: Input>(input: &mut I) -> Result<Self, codec::Error> {
+		let Compact(size): Compact<u32> = Decode::decode(input)?;
+		if size != N as u32 {
+			return Err("Invalid size".into());
+		}
+
+		let bytes: [u8; N] = Decode::decode(input)?;
+		Ok(Self(bytes))
+	}
+}
+
 /// Detailed information about the configuration of a referenda track
 #[derive(
 	Clone, Encode, Decode, DecodeWithMemTracking, MaxEncodedLen, TypeInfo, Eq, PartialEq, Debug,
 )]
 pub struct TrackInfo<Balance, Moment, const N: usize = DEFAULT_MAX_TRACK_NAME_LEN> {
 	/// Name of this track.
-	pub name: [u8; N],
+	pub name: StringLike<N>,
 	/// A limit for the number of referenda on this track that can be being decided at once.
 	/// For Root origin this should generally be just one.
 	pub max_deciding: u32,
@@ -584,7 +627,7 @@ impl Debug for Curve {
 mod tests {
 	use super::*;
 	use frame_support::traits::ConstU32;
-	use sp_runtime::{str_array as s, PerThing};
+	use sp_runtime::PerThing;
 
 	const fn percent(x: u128) -> FixedI64 {
 		FixedI64::from_rational(x, 100)
@@ -741,7 +784,7 @@ mod tests {
 					Track {
 						id: 1u8,
 						info: TrackInfo {
-							name: s("root"),
+							name: string_like_track_name("root"),
 							max_deciding: 1,
 							decision_deposit: 10,
 							prepare_period: 4,
@@ -763,7 +806,7 @@ mod tests {
 					Track {
 						id: 0u8,
 						info: TrackInfo {
-							name: s("none"),
+							name: string_like_track_name("none"),
 							max_deciding: 3,
 							decision_deposit: 1,
 							prepare_period: 2,