Use v2 for now

frame/support/src/storage/mod.rs

@@ -1160,7 +1160,7 @@ pub trait StoragePrefixedMap<Value: FullCodec> {
 	/// removed and the same result being returned. This happens because the keys to delete in the
 	/// overlay are not taken into account when deleting keys in the backend.
 	fn clear(limit: Option<u32>) -> sp_io::ClearPrefixResult {
-		sp_io::storage::clear_prefix(&Self::final_prefix(), limit)
+		unhashed::clear_prefix(&Self::final_prefix(), limit)
 	}
 
 	/// Iter over all value of the storage.

frame/support/src/storage/unhashed.rs

@@ -98,12 +98,22 @@ pub fn kill(key: &[u8]) {
 /// Ensure keys with the given `prefix` have no entries in storage.
 #[deprecated = "Use `clear_prefix` instead"]
 pub fn kill_prefix(prefix: &[u8], limit: Option<u32>) -> sp_io::KillStorageResult {
-	clear_prefix(prefix, limit).into()
+	// TODO: Once the network has upgraded to include the new host functions, this code can be
+	// enabled.
+	// clear_prefix(prefix, limit).into()
+	sp_io::storage::clear_prefix(prefix, limit)
 }
 
 /// Ensure keys with the given `prefix` have no entries in storage.
 pub fn clear_prefix(prefix: &[u8], limit: Option<u32>) -> sp_io::ClearPrefixResult {
-	sp_io::storage::clear_prefix(prefix, limit)
+	// TODO: Once the network has upgraded to include the new host functions, this code can be
+	// enabled.
+	// sp_io::storage::clear_prefix(prefix, limit)
+	use sp_io::{KillStorageResult::*, ClearPrefixResult::*};
+	match kill_prefix(prefix, limit) {
+		AllRemoved(db) => NoneLeft { db, total: db },
+		SomeRemaining(db) => SomeLeft { db, total: db },
+	}
 }
 
 /// Get a Vec of bytes from storage.

primitives/io/src/lib.rs

@@ -236,7 +236,7 @@ pub trait Storage {
 	/// every time this function is called with the exact same arguments per block. This happens
 	/// because the keys in the overlay are not taken into account when deleting keys in the
 	/// backend.
-	#[version(3)]
+	#[version(3, register_only)]
 	fn clear_prefix(&mut self, prefix: &[u8], limit: Option<u32>) -> ClearPrefixResult {
 		let (all_removed, db, total) = Externalities::clear_prefix(*self, prefix, limit);
 		match all_removed {