Do not return empty entries from state_queryStorage (#2906)

* do not return empty entries from state_queryStorage

* revert back None -> null change

* Revert "revert back None -> null change"

This reverts commit 318eb043e03b7aabbc3f176e02c15fd4595d16db.

substrate/core/test-runtime/client/src/block_builder_ext.rs

@@ -25,6 +25,8 @@ use generic_test_client::client::block_builder::api::BlockBuilder;
 pub trait BlockBuilderExt {
 	/// Add transfer extrinsic to the block.
 	fn push_transfer(&mut self, transfer: runtime::Transfer) -> Result<(), client::error::Error>;
+	/// Add storage change extrinsic to the block.
+	fn push_storage_change(&mut self, key: Vec<u8>, value: Option<Vec<u8>>) -> Result<(), client::error::Error>;
 }
 
 impl<'a, A> BlockBuilderExt for client::block_builder::BlockBuilder<'a, runtime::Block, A> where
@@ -34,4 +36,8 @@ impl<'a, A> BlockBuilderExt for client::block_builder::BlockBuilder<'a, runtime:
 	fn push_transfer(&mut self, transfer: runtime::Transfer) -> Result<(), client::error::Error> {
 		self.push(transfer.into_signed_tx())
 	}
+
+	fn push_storage_change(&mut self, key: Vec<u8>, value: Option<Vec<u8>>) -> Result<(), client::error::Error> {
+		self.push(runtime::Extrinsic::StorageChange(key, value))
+	}
 }

substrate/core/test-runtime/src/lib.rs

@@ -106,6 +106,7 @@ pub enum Extrinsic {
 	AuthoritiesChange(Vec<AuthorityId>),
 	Transfer(Transfer, AccountSignature),
 	IncludeData(Vec<u8>),
+	StorageChange(Vec<u8>, Option<Vec<u8>>),
 }
 
 #[cfg(feature = "std")]
@@ -129,6 +130,7 @@ impl BlindCheckable for Extrinsic {
 				}
 			},
 			Extrinsic::IncludeData(_) => Err(runtime_primitives::BAD_SIGNATURE),
+			Extrinsic::StorageChange(key, value) => Ok(Extrinsic::StorageChange(key, value)),
 		}
 	}
 }

substrate/core/test-runtime/src/system.rs

@@ -238,6 +238,7 @@ fn execute_transaction_backend(utx: &Extrinsic) -> ApplyResult {
 		Extrinsic::Transfer(ref transfer, _) => execute_transfer_backend(transfer),
 		Extrinsic::AuthoritiesChange(ref new_auth) => execute_new_authorities_backend(new_auth),
 		Extrinsic::IncludeData(_) => Ok(ApplyOutcome::Success),
+		Extrinsic::StorageChange(key, value) => execute_storage_change(key, value.as_ref().map(|v| &**v)),
 	}
 }
 
@@ -273,6 +274,14 @@ fn execute_new_authorities_backend(new_authorities: &[AuthorityId]) -> ApplyResu
 	Ok(ApplyOutcome::Success)
 }
 
+fn execute_storage_change(key: &[u8], value: Option<&[u8]>) -> ApplyResult {
+	match value {
+		Some(value) => storage::unhashed::put_raw(key, value),
+		None => storage::unhashed::kill(key),
+	}
+	Ok(ApplyOutcome::Success)
+}
+
 #[cfg(feature = "std")]
 fn info_expect_equal_hash(given: &Hash, expected: &Hash) {
 	use primitives::hexdisplay::HexDisplay;