fix: undecodable ForeignInvestmentInfo on Demo

pallets/foreign-investments/src/lib.rs

@@ -228,7 +228,7 @@ pub mod pallet {
 	/// NOTE: The storage is killed once the investment is fully collected, or
 	/// decreased.
 	#[pallet::storage]
-	pub(super) type ForeignInvestmentInfo<T: Config> = StorageDoubleMap<
+	pub type ForeignInvestmentInfo<T: Config> = StorageDoubleMap<
 		_,
 		Blake2_128Concat,
 		T::AccountId,

runtime/common/src/migrations/mod.rs

@@ -15,3 +15,58 @@
 pub mod increase_storage_version;
 pub mod nuke;
 pub mod precompile_account_codes;
+
+pub mod utils {
+	use frame_support::storage::unhashed;
+	use sp_arithmetic::traits::Saturating;
+
+	/// Iterates keys of storage and removes undecodable keys
+	///
+	/// WARNING: USE WITH EXTREME CAUTION! Ensure the cleanup can be performed
+	/// beforehand!
+	pub fn remove_undecodable_storage_keys<T: parity_scale_codec::Decode + Sized>(
+		prefix: [u8; 32],
+	) -> (u64, u64) {
+		let mut previous_key = prefix.clone().to_vec();
+		let mut reads: u64 = 1;
+		let mut writes: u64 = 0;
+		while let Some(next) =
+			sp_io::storage::next_key(&previous_key).filter(|n| n.starts_with(&prefix))
+		{
+			reads.saturating_accrue(1);
+			previous_key = next;
+			let maybe_value = unhashed::get::<T>(&previous_key);
+			match maybe_value {
+				Some(_) => continue,
+				None => {
+					log::debug!(
+						"Removing key which could not be decoded at {:?}",
+						previous_key
+					);
+					unhashed::kill(&previous_key);
+					writes.saturating_accrue(1);
+					continue;
+				}
+			}
+		}
+
+		(reads, writes)
+	}
+
+	/// Iterates all keys of a storage and returns the count.
+	///
+	/// NOTE: Necessary because `Storage::<T>::iter().count()` does not account
+	/// for keys which cannot be decoded.
+	pub fn count_storage_keys(prefix: [u8; 32]) -> u32 {
+		let mut previous_key = prefix.clone().to_vec();
+		let mut n: u32 = 0;
+		while let Some(next) =
+			sp_io::storage::next_key(&previous_key).filter(|n| n.starts_with(&prefix))
+		{
+			n.saturating_accrue(1);
+			previous_key = next;
+		}
+
+		n
+	}
+}