srml: system: prune block hash mapping (#3062)

* srml: system: prune block number to hash mapping

* srml: system: add test for block hash mapping pruning

* node: bump runtime version

* srml: system: wrap long line

* srml: system: use parameter type for block hash count

* srml: system: prune block hash mapping before storage root calculation

* srml: system: keep the genesis hash in block number map

substrate/node-template/runtime/src/lib.rs

@@ -111,6 +111,10 @@ pub fn native_version() -> NativeVersion {
 	}
 }
 
+parameter_types! {
+	pub const BlockHashCount: BlockNumber = 250;
+}
+
 impl system::Trait for Runtime {
 	/// The identifier used to distinguish between accounts.
 	type AccountId = AccountId;
@@ -130,6 +134,8 @@ impl system::Trait for Runtime {
 	type Event = Event;
 	/// The ubiquitous origin type.
 	type Origin = Origin;
+	/// Maximum number of block number to block hash mappings to keep (oldest pruned first).
+	type BlockHashCount = BlockHashCount;
 }
 
 impl aura::Trait for Runtime {

substrate/node-template/runtime/src/template.rs

@@ -71,7 +71,7 @@ mod tests {
 
 	use runtime_io::with_externalities;
 	use primitives::{H256, Blake2Hasher};
-	use support::{impl_outer_origin, assert_ok};
+	use support::{impl_outer_origin, assert_ok, parameter_types};
 	use runtime_primitives::{traits::{BlakeTwo256, IdentityLookup}, testing::Header};
 
 	impl_outer_origin! {
@@ -83,6 +83,9 @@ mod tests {
 	// configuration traits of modules we want to use.
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -93,6 +96,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	impl Trait for Test {
 		type Event = ();

substrate/node/runtime/src/lib.rs

@@ -71,8 +71,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// and set impl_version to equal spec_version. If only runtime
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
-	spec_version: 106,
-	impl_version: 106,
+	spec_version: 107,
+	impl_version: 107,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -111,6 +111,10 @@ pub const MINUTES: Moment = 60 / SECS_PER_BLOCK;
 pub const HOURS: Moment = MINUTES * 60;
 pub const DAYS: Moment = HOURS * 24;
 
+parameter_types! {
+	pub const BlockHashCount: BlockNumber = 250;
+}
+
 impl system::Trait for Runtime {
 	type Origin = Origin;
 	type Index = Index;
@@ -121,6 +125,7 @@ impl system::Trait for Runtime {
 	type Lookup = Indices;
 	type Header = generic::Header<BlockNumber, BlakeTwo256>;
 	type Event = Event;
+	type BlockHashCount = BlockHashCount;
 }
 
 impl aura::Trait for Runtime {

substrate/srml/assets/src/lib.rs

@@ -240,7 +240,7 @@ mod tests {
 	use super::*;
 
 	use runtime_io::with_externalities;
-	use srml_support::{impl_outer_origin, assert_ok, assert_noop};
+	use srml_support::{impl_outer_origin, assert_ok, assert_noop, parameter_types};
 	use substrate_primitives::{H256, Blake2Hasher};
 	// The testing primitives are very useful for avoiding having to work with signatures
 	// or public keys. `u64` is used as the `AccountId` and no `Signature`s are required.
@@ -255,6 +255,9 @@ mod tests {
 	// configuration traits of modules we want to use.
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -265,6 +268,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	impl Trait for Test {
 		type Event = ();

substrate/srml/aura/src/mock.rs

@@ -23,7 +23,7 @@ use primitives::{
 	traits::IdentityLookup,
 	testing::{UINT_DUMMY_KEY, Header, UintAuthorityId},
 };
-use srml_support::impl_outer_origin;
+use srml_support::{impl_outer_origin, parameter_types};
 use runtime_io;
 use substrate_primitives::{H256, Blake2Hasher};
 use crate::{Trait, Module, GenesisConfig};
@@ -36,6 +36,10 @@ impl_outer_origin!{
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Test;
 
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
+
 impl system::Trait for Test {
 	type Origin = Origin;
 	type Index = u64;
@@ -46,6 +50,7 @@ impl system::Trait for Test {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = ();
+	type BlockHashCount = BlockHashCount;
 }
 
 impl timestamp::Trait for Test {

substrate/srml/authorship/src/lib.rs

@@ -335,6 +335,10 @@ mod tests {
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
 
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
+
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -345,6 +349,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 
 	impl Trait for Test {

substrate/srml/balances/src/lib.rs

@@ -746,6 +746,7 @@ impl<T: Subtrait<I>, I: Instance> system::Trait for ElevatedTrait<T, I> {
 	type Lookup = T::Lookup;
 	type Header = T::Header;
 	type Event = ();
+	type BlockHashCount = T::BlockHashCount;
 }
 impl<T: Subtrait<I>, I: Instance> Trait<I> for ElevatedTrait<T, I> {
 	type Balance = T::Balance;

substrate/srml/balances/src/mock.rs

@@ -21,7 +21,7 @@
 use primitives::{traits::{IdentityLookup}, testing::Header};
 use substrate_primitives::{H256, Blake2Hasher};
 use runtime_io;
-use srml_support::{impl_outer_origin, traits::Get};
+use srml_support::{impl_outer_origin, parameter_types, traits::Get};
 use std::cell::RefCell;
 use crate::{GenesisConfig, Module, Trait};
 
@@ -65,6 +65,9 @@ impl Get<u64> for TransactionByteFee {
 // Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Runtime;
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Runtime {
 	type Origin = Origin;
 	type Index = u64;
@@ -75,6 +78,7 @@ impl system::Trait for Runtime {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = ();
+	type BlockHashCount = BlockHashCount;
 }
 impl Trait for Runtime {
 	type Balance = u64;

substrate/srml/contracts/src/tests.rs

@@ -94,6 +94,9 @@ impl Get<u64> for BlockGasLimit {
 
 #[derive(Clone, Eq, PartialEq, Debug)]
 pub struct Test;
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Test {
 	type Origin = Origin;
 	type Index = u64;
@@ -104,6 +107,7 @@ impl system::Trait for Test {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = MetaEvent;
+	type BlockHashCount = BlockHashCount;
 }
 parameter_types! {
 	pub const BalancesTransactionBaseFee: u64 = 0;

substrate/srml/council/src/lib.rs

@@ -96,6 +96,9 @@ mod tests {
 	// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 	#[derive(Clone, Eq, PartialEq, Debug)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -106,6 +109,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = Event;
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const ExistentialDeposit: u64 = 0;

substrate/srml/democracy/src/lib.rs

@@ -971,6 +971,9 @@ mod tests {
 	// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 	#[derive(Clone, Eq, PartialEq, Debug)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -981,6 +984,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const ExistentialDeposit: u64 = 0;

substrate/srml/example/src/lib.rs

@@ -523,6 +523,9 @@ mod tests {
 	// configuration traits of modules we want to use.
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -533,6 +536,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const ExistentialDeposit: u64 = 0;

substrate/srml/executive/src/lib.rs

@@ -416,6 +416,9 @@ mod tests {
 	// Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Runtime;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Runtime {
 		type Origin = Origin;
 		type Index = u64;
@@ -426,6 +429,7 @@ mod tests {
 		type Lookup = IdentityLookup<u64>;
 		type Header = Header;
 		type Event = MetaEvent;
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const ExistentialDeposit: u64 = 0;

substrate/srml/finality-tracker/src/lib.rs

@@ -297,6 +297,9 @@ mod tests {
 		}
 	}
 
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -307,6 +310,7 @@ mod tests {
 		type Lookup = IdentityLookup<u64>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const WindowSize: u64 = 11;

substrate/srml/grandpa/src/mock.rs

@@ -20,7 +20,7 @@
 
 use primitives::{DigestItem, traits::IdentityLookup, testing::{Header, UintAuthorityId}};
 use runtime_io;
-use srml_support::{impl_outer_origin, impl_outer_event};
+use srml_support::{impl_outer_origin, impl_outer_event, parameter_types};
 use substrate_primitives::{H256, Blake2Hasher};
 use parity_codec::{Encode, Decode};
 use crate::{AuthorityId, GenesisConfig, Trait, Module, ConsensusLog};
@@ -41,6 +41,9 @@ impl Trait for Test {
 	type Event = TestEvent;
 
 }
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Test {
 	type Origin = Origin;
 	type Index = u64;
@@ -51,6 +54,7 @@ impl system::Trait for Test {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = TestEvent;
+	type BlockHashCount = BlockHashCount;
 }
 
 mod grandpa {

substrate/srml/indices/src/mock.rs

@@ -22,7 +22,7 @@ use std::collections::HashSet;
 use ref_thread_local::{ref_thread_local, RefThreadLocal};
 use primitives::testing::Header;
 use substrate_primitives::{H256, Blake2Hasher};
-use srml_support::impl_outer_origin;
+use srml_support::{impl_outer_origin, parameter_types};
 use {runtime_io, system};
 use crate::{GenesisConfig, Module, Trait, IsDeadAccount, OnNewAccount, ResolveHint};
 
@@ -64,6 +64,9 @@ impl ResolveHint<u64, u64> for TestResolveHint {
 // Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Runtime;
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Runtime {
 	type Origin = Origin;
 	type Index = u64;
@@ -74,6 +77,7 @@ impl system::Trait for Runtime {
 	type Lookup = Indices;
 	type Header = Header;
 	type Event = ();
+	type BlockHashCount = BlockHashCount;
 }
 impl Trait for Runtime {
 	type AccountIndex = u64;

substrate/srml/session/src/mock.rs

@@ -18,7 +18,7 @@
 
 use super::*;
 use std::cell::RefCell;
-use srml_support::impl_outer_origin;
+use srml_support::{impl_outer_origin, parameter_types};
 use substrate_primitives::H256;
 use primitives::{
 	traits::{BlakeTwo256, IdentityLookup, ConvertInto},
@@ -107,6 +107,9 @@ pub fn set_next_validators(next: Vec<u64>) {
 
 #[derive(Clone, Eq, PartialEq)]
 pub struct Test;
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Test {
 	type Origin = Origin;
 	type Index = u64;
@@ -117,6 +120,7 @@ impl system::Trait for Test {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = ();
+	type BlockHashCount = BlockHashCount;
 }
 impl timestamp::Trait for Test {
 	type Moment = u64;

substrate/srml/staking/src/mock.rs

@@ -86,6 +86,9 @@ impl_outer_origin!{
 // Workaround for https://github.com/rust-lang/rust/issues/26925 . Remove when sorted.
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct Test;
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
 impl system::Trait for Test {
 	type Origin = Origin;
 	type Index = u64;
@@ -96,6 +99,7 @@ impl system::Trait for Test {
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
 	type Event = ();
+	type BlockHashCount = BlockHashCount;
 }
 parameter_types! {
 	pub const TransferFee: u64 = 0;

substrate/srml/system/src/lib.rs

@@ -79,17 +79,15 @@ use rstd::map;
 use primitives::{generic, traits::{self, CheckEqual, SimpleArithmetic,
 	SimpleBitOps, Hash, Member, MaybeDisplay, EnsureOrigin, CurrentHeight, BlockNumberToHash,
 	MaybeSerializeDebugButNotDeserialize, MaybeSerializeDebug, StaticLookup, One, Bounded, Lookup,
+	Zero,
 }};
-#[cfg(any(feature = "std", test))]
-use primitives::traits::Zero;
 use substrate_primitives::storage::well_known_keys;
 use srml_support::{
 	storage, decl_module, decl_event, decl_storage, StorageDoubleMap, StorageValue,
-	StorageMap, Parameter, for_each_tuple, traits::Contains,
+	StorageMap, Parameter, for_each_tuple, traits::{Contains, Get},
 };
 use safe_mix::TripletMix;
 use parity_codec::{Encode, Decode};
-use crate::{self as system};
 
 #[cfg(any(feature = "std", test))]
 use runtime_io::{twox_128, TestExternalities, Blake2Hasher};
@@ -184,6 +182,9 @@ pub trait Trait: 'static + Eq + Clone {
 
 	/// The aggregated event type of the runtime.
 	type Event: Parameter + Member + From<Event>;
+
+	/// Maximum number of block number to block hash mappings to keep (oldest pruned first).
+	type BlockHashCount: Get<Self::BlockNumber>;
 }
 
 pub type DigestOf<T> = generic::Digest<<T as Trait>::Hash>;
@@ -570,6 +571,18 @@ impl<T: Trait> Module<T> {
 		let parent_hash = <ParentHash<T>>::take();
 		let mut digest = <Digest<T>>::take();
 		let extrinsics_root = <ExtrinsicsRoot<T>>::take();
+
+		// move block hash pruning window by one block
+		let block_hash_count = <T::BlockHashCount>::get();
+		if number > block_hash_count {
+			let to_remove = number - block_hash_count - One::one();
+
+			// keep genesis hash
+			if to_remove != Zero::zero() {
+				<BlockHash<T>>::remove(to_remove);
+			}
+		}
+
 		let storage_root = T::Hashing::storage_root();
 		let storage_changes_root = T::Hashing::storage_changes_root(parent_hash);
 
@@ -771,7 +784,7 @@ mod tests {
 	use runtime_io::with_externalities;
 	use substrate_primitives::H256;
 	use primitives::{traits::{BlakeTwo256, IdentityLookup}, testing::Header};
-	use srml_support::impl_outer_origin;
+	use srml_support::{impl_outer_origin, parameter_types};
 
 	impl_outer_origin!{
 		pub enum Origin for Test where system = super {}
@@ -779,6 +792,11 @@ mod tests {
 
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+
+	parameter_types! {
+		pub const BlockHashCount: u64 = 10;
+	}
+
 	impl Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -789,6 +807,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = u16;
+		type BlockHashCount = BlockHashCount;
 	}
 
 	impl From<Event> for u16 {
@@ -906,4 +925,37 @@ mod tests {
 			);
 		});
 	}
+
+	#[test]
+	fn prunes_block_hash_mappings() {
+		with_externalities(&mut new_test_ext(), || {
+			// simulate import of 15 blocks
+			for n in 1..=15 {
+				System::initialize(
+					&n,
+					&[n as u8 - 1; 32].into(),
+					&[0u8; 32].into(),
+					&Default::default(),
+				);
+
+				System::finalize();
+			}
+
+			// first 5 block hashes are pruned
+			for n in 0..5 {
+				assert_eq!(
+					System::block_hash(n),
+					H256::zero(),
+				);
+			}
+
+			// the remaining 10 are kept
+			for n in 5..15 {
+				assert_eq!(
+					System::block_hash(n),
+					[n as u8; 32].into(),
+				);
+			}
+		})
+	}
 }

substrate/srml/timestamp/src/lib.rs

@@ -330,7 +330,7 @@ impl<T: Trait> ProvideInherent for Module<T> {
 mod tests {
 	use super::*;
 
-	use srml_support::{impl_outer_origin, assert_ok};
+	use srml_support::{impl_outer_origin, assert_ok, parameter_types};
 	use runtime_io::{with_externalities, TestExternalities};
 	use substrate_primitives::H256;
 	use runtime_primitives::{traits::{BlakeTwo256, IdentityLookup}, testing::Header};
@@ -341,6 +341,9 @@ mod tests {
 
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -351,6 +354,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	impl Trait for Test {
 		type Moment = u64;

substrate/srml/treasury/src/lib.rs

@@ -368,6 +368,9 @@ mod tests {
 
 	#[derive(Clone, Eq, PartialEq)]
 	pub struct Test;
+	parameter_types! {
+		pub const BlockHashCount: u64 = 250;
+	}
 	impl system::Trait for Test {
 		type Origin = Origin;
 		type Index = u64;
@@ -378,6 +381,7 @@ mod tests {
 		type Lookup = IdentityLookup<Self::AccountId>;
 		type Header = Header;
 		type Event = ();
+		type BlockHashCount = BlockHashCount;
 	}
 	parameter_types! {
 		pub const ExistentialDeposit: u64 = 0;