contracts: Add storage deposits (#10082)

* Frame no longer needs to be mutable (refactoring artifact)

* Remove Contract/Tombstone deposit

* Add StorageMeter

* cargo fmt

* Fix weight annotation

* cargo run --quiet --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_contracts --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/contracts/src/weights.rs --template=./.maintain/frame-weight-template.hbs

* Simplify keep check for contract accounts

- Make sure that the "base deposit" for each contract >= ed
- Remove now obsolete checks when sneding away free balance

* Remove unused imports and functions

* Rename storage_limit to storage_deposit_limit

* cargo fmt

* Fix typo

Co-authored-by: Michael Müller <michi@parity.io>

* Finish up rename of storage_limit

* Fix rpc tests

* Make use of `StorageDepositLimitTooHigh`

* Add tests and fix bugs discovered by tests

* Add storage migration

* Don't use u128 in RPC

* Fix weight of migration

* Rename `endowment` to `value`

* Fix bug where contract couldn't get funded by a storage deposit

- Make sure that contract gets funded from deposits before value is transferred
- Don't reserve value at origin because otherwise funding isn't possible
	- Just transfer free balance and reserve it after the transfer
- When refunding make sure that this refund can't dust the contract
	- Can only happen after a runtime upgrade where costs where upped
- Add more tests

* Apply suggestions from code review

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Remove unused `fn storage_meter`

* Fix copy pasta doc error

* Import `MaxEncodeLen` from codec

* Beautify RPC trait bounds

* Add re-instrument behaviour to dispatchable doc

* Make sure a account won't be destroyed a refund after a slash

* Apply suggestions from code review

Co-authored-by: Andrew Jones <ascjones@gmail.com>

* Update `Storage::write` docs

* Improve doc

* Remove superflous conditional

* Typos

* Remove superflous clone (refactoring artifact)

* Apply suggestions from code review

Co-authored-by: Andrew Jones <ascjones@gmail.com>

Co-authored-by: Parity Bot <admin@parity.io>
Co-authored-by: Michael Müller <michi@parity.io>
Co-authored-by: Andrew Jones <ascjones@gmail.com>

bin/node/executor/Cargo.toml

@@ -20,6 +20,7 @@ sc-executor = { version = "0.10.0-dev", path = "../../../client/executor" }
 sp-core = { version = "4.0.0-dev", path = "../../../primitives/core" }
 sp-keystore = { version = "0.10.0-dev", path = "../../../primitives/keystore" }
 sp-state-machine = { version = "0.10.0-dev", path = "../../../primitives/state-machine" }
+sp-tracing = { version = "4.0.0-dev", path = "../../../primitives/tracing" }
 sp-trie = { version = "4.0.0-dev", path = "../../../primitives/trie" }
 frame-benchmarking = { version = "4.0.0-dev", path = "../../../frame/benchmarking" }
 

bin/node/executor/tests/basic.rs

@@ -685,8 +685,6 @@ fn deploying_wasm_contract_should_work() {
 
 	let addr = pallet_contracts::Pallet::<Runtime>::contract_address(&charlie(), &transfer_ch, &[]);
 
-	let subsistence = pallet_contracts::Pallet::<Runtime>::subsistence_threshold();
-
 	let time = 42 * 1000;
 	let b = construct_block(
 		&mut new_test_ext(compact_code_unwrap()),
@@ -701,8 +699,9 @@ fn deploying_wasm_contract_should_work() {
 				signed: Some((charlie(), signed_extra(0, 0))),
 				function: Call::Contracts(
 					pallet_contracts::Call::instantiate_with_code::<Runtime> {
-						endowment: 1000 * DOLLARS + subsistence,
+						value: 0,
 						gas_limit: 500_000_000,
+						storage_deposit_limit: None,
 						code: transfer_code,
 						data: Vec::new(),
 						salt: Vec::new(),
@@ -715,6 +714,7 @@ fn deploying_wasm_contract_should_work() {
 					dest: sp_runtime::MultiAddress::Id(addr.clone()),
 					value: 10,
 					gas_limit: 500_000_000,
+					storage_deposit_limit: None,
 					data: vec![0x00, 0x01, 0x02, 0x03],
 				}),
 			},

bin/node/executor/tests/common.rs

@@ -119,7 +119,7 @@ pub fn executor_call<
 		hash: sp_core::blake2_256(&code).to_vec(),
 		heap_pages: heap_pages.and_then(|hp| Decode::decode(&mut &hp[..]).ok()),
 	};
-
+	sp_tracing::try_init_simple();
 	executor().call::<R, NC>(&mut t, &runtime_code, method, data, use_native, native_call)
 }
 

bin/node/runtime/src/lib.rs

@@ -897,10 +897,8 @@ impl pallet_tips::Config for Runtime {
 }
 
 parameter_types! {
-	pub ContractDeposit: Balance = deposit(
-		1,
-		<pallet_contracts::Pallet<Runtime>>::contract_info_size(),
-	);
+	pub const DepositPerItem: Balance = deposit(1, 0);
+	pub const DepositPerByte: Balance = deposit(0, 1);
 	pub const MaxValueSize: u32 = 16 * 1024;
 	// The lazy deletion runs inside on_initialize.
 	pub DeletionWeightLimit: Weight = AVERAGE_ON_INITIALIZE_RATIO *
@@ -927,7 +925,8 @@ impl pallet_contracts::Config for Runtime {
 	/// change because that would break already deployed contracts. The `Call` structure itself
 	/// is not allowed to change the indices of existing pallets, too.
 	type CallFilter = Nothing;
-	type ContractDeposit = ContractDeposit;
+	type DepositPerItem = DepositPerItem;
+	type DepositPerByte = DepositPerByte;
 	type CallStack = [pallet_contracts::Frame<Self>; 31];
 	type WeightPrice = pallet_transaction_payment::Pallet<Self>;
 	type WeightInfo = pallet_contracts::weights::SubstrateWeight<Self>;
@@ -1522,21 +1521,32 @@ impl_runtime_apis! {
 			dest: AccountId,
 			value: Balance,
 			gas_limit: u64,
+			storage_deposit_limit: Option<Balance>,
 			input_data: Vec<u8>,
-		) -> pallet_contracts_primitives::ContractExecResult {
-			Contracts::bare_call(origin, dest, value, gas_limit, input_data, true)
+		) -> pallet_contracts_primitives::ContractExecResult<Balance> {
+			Contracts::bare_call(origin, dest, value, gas_limit, storage_deposit_limit, input_data, true)
 		}
 
 		fn instantiate(
 			origin: AccountId,
-			endowment: Balance,
+			value: Balance,
 			gas_limit: u64,
+			storage_deposit_limit: Option<Balance>,
 			code: pallet_contracts_primitives::Code<Hash>,
 			data: Vec<u8>,
 			salt: Vec<u8>,
-		) -> pallet_contracts_primitives::ContractInstantiateResult<AccountId>
+		) -> pallet_contracts_primitives::ContractInstantiateResult<AccountId, Balance>
+		{
+			Contracts::bare_instantiate(origin, value, gas_limit, storage_deposit_limit, code, data, salt, true)
+		}
+
+		fn upload_code(
+			origin: AccountId,
+			code: Vec<u8>,
+			storage_deposit_limit: Option<Balance>,
+		) -> pallet_contracts_primitives::CodeUploadResult<Hash, Balance>
 		{
-			Contracts::bare_instantiate(origin, endowment, gas_limit, code, data, salt, true)
+			Contracts::bare_upload_code(origin, code, storage_deposit_limit)
 		}
 
 		fn get_storage(

frame/contracts/Cargo.toml

@@ -46,6 +46,7 @@ sp-std = { version = "4.0.0-dev", default-features = false, path = "../../primit
 
 [dev-dependencies]
 assert_matches = "1"
+env_logger = "0.9"
 hex-literal = "0.3"
 pretty_assertions = "1"
 wat = "1"

frame/contracts/common/Cargo.toml

@@ -21,6 +21,7 @@ serde = { version = "1", features = ["derive"], optional = true }
 # Substrate Dependencies (This crate should not rely on frame)
 sp-core = { version = "4.0.0-dev", path = "../../../primitives/core", default-features = false }
 sp-std = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/std" }
+sp-rpc = { version = "4.0.0-dev", path = "../../../primitives/rpc", optional = true }
 sp-runtime = { version = "4.0.0-dev", default-features = false, path = "../../../primitives/runtime" }
 
 [features]
@@ -31,5 +32,6 @@ std = [
 	"sp-core/std",
 	"sp-runtime/std",
 	"sp-std/std",
+	"sp-rpc",
 	"serde",
 ]

frame/contracts/common/src/lib.rs

@@ -22,19 +22,32 @@
 use bitflags::bitflags;
 use codec::{Decode, Encode};
 use sp_core::Bytes;
-use sp_runtime::{DispatchError, RuntimeDebug};
+use sp_runtime::{
+	traits::{Saturating, Zero},
+	DispatchError, RuntimeDebug,
+};
 use sp_std::prelude::*;
 
 #[cfg(feature = "std")]
 use serde::{Deserialize, Serialize};
 
+#[cfg(feature = "std")]
+use sp_rpc::number::NumberOrHex;
+
 /// Result type of a `bare_call` or `bare_instantiate` call.
 ///
 /// It contains the execution result together with some auxiliary information.
 #[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
-#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
-pub struct ContractResult<T> {
+#[cfg_attr(
+	feature = "std",
+	serde(
+		rename_all = "camelCase",
+		bound(serialize = "R: Serialize, Balance: Copy + Into<NumberOrHex>"),
+		bound(deserialize = "R: Deserialize<'de>, Balance: TryFrom<NumberOrHex>")
+	)
+)]
+pub struct ContractResult<R, Balance> {
 	/// How much gas was consumed during execution.
 	pub gas_consumed: u64,
 	/// How much gas is required as gas limit in order to execute this call.
@@ -45,7 +58,14 @@ pub struct ContractResult<T> {
 	///
 	/// This can only different from [`Self::gas_consumed`] when weight pre charging
 	/// is used. Currently, only `seal_call_runtime` makes use of pre charging.
+	/// Additionally, any `seal_call` or `seal_instantiate` makes use of pre-charging
+	/// when a non-zero `gas_limit` argument is supplied.
 	pub gas_required: u64,
+	/// How much balance was deposited and reserved during execution in order to pay for storage.
+	///
+	/// The storage deposit is never actually charged from the caller in case of [`Self::result`]
+	/// is `Err`. This is because on error all storage changes are rolled back.
+	pub storage_deposit: StorageDeposit<Balance>,
 	/// An optional debug message. This message is only filled when explicitly requested
 	/// by the code that calls into the contract. Otherwise it is empty.
 	///
@@ -63,15 +83,20 @@ pub struct ContractResult<T> {
 	#[cfg_attr(feature = "std", serde(with = "as_string"))]
 	pub debug_message: Vec<u8>,
 	/// The execution result of the wasm code.
-	pub result: T,
+	pub result: R,
 }
 
 /// Result type of a `bare_call` call.
-pub type ContractExecResult = ContractResult<Result<ExecReturnValue, DispatchError>>;
+pub type ContractExecResult<Balance> =
+	ContractResult<Result<ExecReturnValue, DispatchError>, Balance>;
 
 /// Result type of a `bare_instantiate` call.
-pub type ContractInstantiateResult<AccountId> =
-	ContractResult<Result<InstantiateReturnValue<AccountId>, DispatchError>>;
+pub type ContractInstantiateResult<AccountId, Balance> =
+	ContractResult<Result<InstantiateReturnValue<AccountId>, DispatchError>, Balance>;
+
+/// Result type of a `bare_code_upload` call.
+pub type CodeUploadResult<CodeHash, Balance> =
+	Result<CodeUploadReturnValue<CodeHash, Balance>, DispatchError>;
 
 /// Result type of a `get_storage` call.
 pub type GetStorageResult = Result<Option<Vec<u8>>, ContractAccessError>;
@@ -123,6 +148,17 @@ pub struct InstantiateReturnValue<AccountId> {
 	pub account_id: AccountId,
 }
 
+/// The result of succesfully uploading a contract.
+#[derive(PartialEq, Eq, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "std", serde(rename_all = "camelCase"))]
+pub struct CodeUploadReturnValue<CodeHash, Balance> {
+	/// The key under which the new code is stored.
+	pub code_hash: CodeHash,
+	/// The deposit that was reserved at the caller. Is zero when the code already existed.
+	pub deposit: Balance,
+}
+
 /// Reference to an existing code hash or a new wasm module.
 #[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
@@ -134,6 +170,116 @@ pub enum Code<Hash> {
 	Existing(Hash),
 }
 
+/// The amount of balance that was either charged or refunded in order to pay for storage.
+#[derive(Eq, PartialEq, Ord, PartialOrd, Encode, Decode, RuntimeDebug, Clone)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[cfg_attr(
+	feature = "std",
+	serde(
+		rename_all = "camelCase",
+		bound(serialize = "Balance: Copy + Into<NumberOrHex>"),
+		bound(deserialize = "Balance: TryFrom<NumberOrHex>")
+	)
+)]
+pub enum StorageDeposit<Balance> {
+	/// The transaction reduced storage consumption.
+	///
+	/// This means that the specified amount of balance was transferred from the involved
+	/// contracts to the call origin.
+	#[cfg_attr(feature = "std", serde(with = "as_hex"))]
+	Refund(Balance),
+	/// The transaction increased overall storage usage.
+	///
+	/// This means that the specified amount of balance was transferred from the call origin
+	/// to the contracts involved.
+	#[cfg_attr(feature = "std", serde(with = "as_hex"))]
+	Charge(Balance),
+}
+
+impl<Balance: Zero> Default for StorageDeposit<Balance> {
+	fn default() -> Self {
+		Self::Charge(Zero::zero())
+	}
+}
+
+impl<Balance: Zero + Copy> StorageDeposit<Balance> {
+	/// Returns how much balance is charged or `0` in case of a refund.
+	pub fn charge_or_zero(&self) -> Balance {
+		match self {
+			Self::Charge(amount) => *amount,
+			Self::Refund(_) => Zero::zero(),
+		}
+	}
+
+	pub fn is_zero(&self) -> bool {
+		match self {
+			Self::Charge(amount) => amount.is_zero(),
+			Self::Refund(amount) => amount.is_zero(),
+		}
+	}
+}
+
+impl<Balance> StorageDeposit<Balance>
+where
+	Balance: Saturating + Ord + Copy,
+{
+	/// This is essentially a saturating signed add.
+	pub fn saturating_add(&self, rhs: &Self) -> Self {
+		use StorageDeposit::*;
+		match (self, rhs) {
+			(Charge(lhs), Charge(rhs)) => Charge(lhs.saturating_add(*rhs)),
+			(Refund(lhs), Refund(rhs)) => Refund(lhs.saturating_add(*rhs)),
+			(Charge(lhs), Refund(rhs)) =>
+				if lhs >= rhs {
+					Charge(lhs.saturating_sub(*rhs))
+				} else {
+					Refund(rhs.saturating_sub(*lhs))
+				},
+			(Refund(lhs), Charge(rhs)) =>
+				if lhs > rhs {
+					Refund(lhs.saturating_sub(*rhs))
+				} else {
+					Charge(rhs.saturating_sub(*lhs))
+				},
+		}
+	}
+
+	/// This is essentially a saturating signed sub.
+	pub fn saturating_sub(&self, rhs: &Self) -> Self {
+		use StorageDeposit::*;
+		match (self, rhs) {
+			(Charge(lhs), Refund(rhs)) => Charge(lhs.saturating_add(*rhs)),
+			(Refund(lhs), Charge(rhs)) => Refund(lhs.saturating_add(*rhs)),
+			(Charge(lhs), Charge(rhs)) =>
+				if lhs >= rhs {
+					Charge(lhs.saturating_sub(*rhs))
+				} else {
+					Refund(rhs.saturating_sub(*lhs))
+				},
+			(Refund(lhs), Refund(rhs)) =>
+				if lhs > rhs {
+					Refund(lhs.saturating_sub(*rhs))
+				} else {
+					Charge(rhs.saturating_sub(*lhs))
+				},
+		}
+	}
+
+	/// If the amount of deposit (this type) is constrained by a `limit` this calcuates how
+	/// much balance (if any) is still available from this limit.
+	///
+	/// # Note
+	///
+	/// In case of a refund the return value can be larger than `limit`.
+	pub fn available(&self, limit: &Balance) -> Balance {
+		use StorageDeposit::*;
+		match self {
+			Charge(amount) => limit.saturating_sub(*amount),
+			Refund(amount) => limit.saturating_add(*amount),
+		}
+	}
+}
+
 #[cfg(feature = "std")]
 mod as_string {
 	use super::*;
@@ -149,3 +295,26 @@ mod as_string {
 		Ok(String::deserialize(deserializer)?.into_bytes())
 	}
 }
+
+#[cfg(feature = "std")]
+mod as_hex {
+	use super::*;
+	use serde::{de::Error as _, Deserializer, Serializer};
+
+	pub fn serialize<S, Balance>(balance: &Balance, serializer: S) -> Result<S::Ok, S::Error>
+	where
+		S: Serializer,
+		Balance: Copy + Into<NumberOrHex>,
+	{
+		Into::<NumberOrHex>::into(*balance).serialize(serializer)
+	}
+
+	pub fn deserialize<'de, D, Balance>(deserializer: D) -> Result<Balance, D::Error>
+	where
+		D: Deserializer<'de>,
+		Balance: TryFrom<NumberOrHex>,
+	{
+		Balance::try_from(NumberOrHex::deserialize(deserializer)?)
+			.map_err(|_| D::Error::custom("Cannot decode NumberOrHex to Balance"))
+	}
+}

frame/contracts/fixtures/destroy_and_transfer.wat

@@ -9,7 +9,7 @@
 	))
 	(import "env" "memory" (memory 1 1))
 
-	;; [0, 8) Endowment to send when creating contract.
+	;; [0, 8) value to send when creating contract.
 	(data (i32.const 0) "\00\00\01")
 
 	;; [8, 16) Value to send when calling contract.