FRAME: Create TransactionExtension as a replacement for SignedExtension (#2280)

Closes #2160 First part of [Extrinsic Horizon](https://github.com/paritytech/polkadot-sdk/issues/2415) Introduces a new trait `TransactionExtension` to replace `SignedExtension`. Introduce the idea of transactions which obey the runtime's extensions and have according Extension data (né Extra data) yet do not have hard-coded signatures. Deprecate the terminology of "Unsigned" when used for transactions/extrinsics owing to there now being "proper" unsigned transactions which obey the extension framework and "old-style" unsigned which do not. Instead we have __*General*__ for the former and __*Bare*__ for the latter. (Ultimately, the latter will be phased out as a type of transaction, and Bare will only be used for Inherents.) Types of extrinsic are now therefore: - Bare (no hardcoded signature, no Extra data; used to be known as "Unsigned") - Bare transactions (deprecated): Gossiped, validated with `ValidateUnsigned` (deprecated) and the `_bare_compat` bits of `TransactionExtension` (deprecated). - Inherents: Not gossiped, validated with `ProvideInherent`. - Extended (Extra data): Gossiped, validated via `TransactionExtension`. - Signed transactions (with a hardcoded signature). - General transactions (without a hardcoded signature). `TransactionExtension` differs from `SignedExtension` because: - A signature on the underlying transaction may validly not be present. - It may alter the origin during validation. - `pre_dispatch` is renamed to `prepare` and need not contain the checks present in `validate`. - `validate` and `prepare` is passed an `Origin` rather than a `AccountId`. - `validate` may pass arbitrary information into `prepare` via a new user-specifiable type `Val`. - `AdditionalSigned`/`additional_signed` is renamed to `Implicit`/`implicit`. It is encoded *for the entire transaction* and passed in to each extension as a new argument to `validate`. This facilitates the ability of extensions to acts as underlying crypto. There is a new `DispatchTransaction` trait which contains only default function impls and is impl'ed for any `TransactionExtension` impler. It provides several utility functions which reduce some of the tedium from using `TransactionExtension` (indeed, none of its regular functions should now need to be called directly). Three transaction version discriminator ("versions") are now permissible: - 0b000000100: Bare (used to be called "Unsigned"): contains Signature or Extra (extension data). After bare transactions are no longer supported, this will strictly identify an Inherents only. - 0b100000100: Old-school "Signed" Transaction: contains Signature and Extra (extension data). - 0b010000100: New-school "General" Transaction: contains Extra (extension data), but no Signature. For the New-school General Transaction, it becomes trivial for authors to publish extensions to the mechanism for authorizing an Origin, e.g. through new kinds of key-signing schemes, ZK proofs, pallet state, mutations over pre-authenticated origins or any combination of the above. ## Code Migration ### NOW: Getting it to build Wrap your `SignedExtension`s in `AsTransactionExtension`. This should be accompanied by renaming your aggregate type in line with the new terminology. E.g. Before: ```rust /// The SignedExtension to the basic transaction logic. pub type SignedExtra = ( /* snip */ MySpecialSignedExtension, ); /// Unchecked extrinsic type as expected by this runtime. pub type UncheckedExtrinsic = generic::UncheckedExtrinsic<Address, RuntimeCall, Signature, SignedExtra>; ``` After: ```rust /// The extension to the basic transaction logic. pub type TxExtension = ( /* snip */ AsTransactionExtension<MySpecialSignedExtension>, ); /// Unchecked extrinsic type as expected by this runtime. pub type UncheckedExtrinsic = generic::UncheckedExtrinsic<Address, RuntimeCall, Signature, TxExtension>; ``` You'll also need to alter any transaction building logic to add a `.into()` to make the conversion happen. E.g. Before: ```rust fn construct_extrinsic( /* snip */ ) -> UncheckedExtrinsic { let extra: SignedExtra = ( /* snip */ MySpecialSignedExtension::new(/* snip */), ); let payload = SignedPayload::new(call.clone(), extra.clone()).unwrap(); let signature = payload.using_encoded(|e| sender.sign(e)); UncheckedExtrinsic::new_signed( /* snip */ Signature::Sr25519(signature), extra, ) } ``` After: ```rust fn construct_extrinsic( /* snip */ ) -> UncheckedExtrinsic { let tx_ext: TxExtension = ( /* snip */ MySpecialSignedExtension::new(/* snip */).into(), ); let payload = SignedPayload::new(call.clone(), tx_ext.clone()).unwrap(); let signature = payload.using_encoded(|e| sender.sign(e)); UncheckedExtrinsic::new_signed( /* snip */ Signature::Sr25519(signature), tx_ext, ) } ``` ### SOON: Migrating to `TransactionExtension` Most `SignedExtension`s can be trivially converted to become a `TransactionExtension`. There are a few things to know. - Instead of a single trait like `SignedExtension`, you should now implement two traits individually: `TransactionExtensionBase` and `TransactionExtension`. - Weights are now a thing and must be provided via the new function `fn weight`. #### `TransactionExtensionBase` This trait takes care of anything which is not dependent on types specific to your runtime, most notably `Call`. - `AdditionalSigned`/`additional_signed` is renamed to `Implicit`/`implicit`. - Weight must be returned by implementing the `weight` function. If your extension is associated with a pallet, you'll probably want to do this via the pallet's existing benchmarking infrastructure. #### `TransactionExtension` Generally: - `pre_dispatch` is now `prepare` and you *should not reexecute the `validate` functionality in there*! - You don't get an account ID any more; you get an origin instead. If you need to presume an account ID, then you can use the trait function `AsSystemOriginSigner::as_system_origin_signer`. - You get an additional ticket, similar to `Pre`, called `Val`. This defines data which is passed from `validate` into `prepare`. This is important since you should not be duplicating logic from `validate` to `prepare`, you need a way of passing your working from the former into the latter. This is it. - This trait takes two type parameters: `Call` and `Context`. `Call` is the runtime call type which used to be an associated type; you can just move it to become a type parameter for your trait impl. `Context` is not currently used and you can safely implement over it as an unbounded type. - There's no `AccountId` associated type any more. Just remove it. Regarding `validate`: - You get three new parameters in `validate`; all can be ignored when migrating from `SignedExtension`. - `validate` returns a tuple on success; the second item in the tuple is the new ticket type `Self::Val` which gets passed in to `prepare`. If you use any information extracted during `validate` (off-chain and on-chain, non-mutating) in `prepare` (on-chain, mutating) then you can pass it through with this. For the tuple's last item, just return the `origin` argument. Regarding `prepare`: - This is renamed from `pre_dispatch`, but there is one change: - FUNCTIONALITY TO VALIDATE THE TRANSACTION NEED NOT BE DUPLICATED FROM `validate`!! - (This is different to `SignedExtension` which was required to run the same checks in `pre_dispatch` as in `validate`.) Regarding `post_dispatch`: - Since there are no unsigned transactions handled by `TransactionExtension`, `Pre` is always defined, so the first parameter is `Self::Pre` rather than `Option<Self::Pre>`. If you make use of `SignedExtension::validate_unsigned` or `SignedExtension::pre_dispatch_unsigned`, then: - Just use the regular versions of these functions instead. - Have your logic execute in the case that the `origin` is `None`. - Ensure your transaction creation logic creates a General Transaction rather than a Bare Transaction; this means having to include all `TransactionExtension`s' data. - `ValidateUnsigned` can still be used (for now) if you need to be able to construct transactions which contain none of the extension data, however these will be phased out in stage 2 of the Transactions Horizon, so you should consider moving to an extension-centric design. ## TODO - [x] Introduce `CheckSignature` impl of `TransactionExtension` to ensure it's possible to have crypto be done wholly in a `TransactionExtension`. - [x] Deprecate `SignedExtension` and move all uses in codebase to `TransactionExtension`. - [x] `ChargeTransactionPayment` - [x] `DummyExtension` - [x] `ChargeAssetTxPayment` (asset-tx-payment) - [x] `ChargeAssetTxPayment` (asset-conversion-tx-payment) - [x] `CheckWeight` - [x] `CheckTxVersion` - [x] `CheckSpecVersion` - [x] `CheckNonce` - [x] `CheckNonZeroSender` - [x] `CheckMortality` - [x] `CheckGenesis` - [x] `CheckOnlySudoAccount` - [x] `WatchDummy` - [x] `PrevalidateAttests` - [x] `GenericSignedExtension` - [x] `SignedExtension` (chain-polkadot-bulletin) - [x] `RefundSignedExtensionAdapter` - [x] Implement `fn weight` across the board. - [ ] Go through all pre-existing extensions which assume an account signer and explicitly handle the possibility of another kind of origin. - [x] `CheckNonce` should probably succeed in the case of a non-account origin. - [x] `CheckNonZeroSender` should succeed in the case of a non-account origin. - [x] `ChargeTransactionPayment` and family should fail in the case of a non-account origin. - [ ] - [x] Fix any broken tests. --------- Signed-off-by: georgepisaltu <george.pisaltu@parity.io> Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io> Signed-off-by: dependabot[bot] <support@github.com> Signed-off-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io> Signed-off-by: Alexandru Gheorghe <alexandru.gheorghe@parity.io> Signed-off-by: Andrei Sandu <andrei-mihail@parity.io> Co-authored-by: Nikhil Gupta <17176722+gupnik@users.noreply.github.com> Co-authored-by: georgepisaltu <52418509+georgepisaltu@users.noreply.github.com> Co-authored-by: Chevdor <chevdor@users.noreply.github.com> Co-authored-by: Bastian Köcher <git@kchr.de> Co-authored-by: Maciej <maciej.zyszkiewicz@parity.io> Co-authored-by: Javier Viola <javier@parity.io> Co-authored-by: Marcin S. <marcin@realemail.net> Co-authored-by: Tsvetomir Dimitrov <tsvetomir@parity.io> Co-authored-by: Javier Bullrich <javier@bullrich.dev> Co-authored-by: Koute <koute@users.noreply.github.com> Co-authored-by: Adrian Catangiu <adrian@parity.io> Co-authored-by: Vladimir Istyufeev <vladimir@parity.io> Co-authored-by: Ross 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2026-06-13 17:31:05 +00:00 · 2024-03-04 20:12:43 +01:00
parent b0741d4f78
commit fd5f9292f5
349 changed files with 25581 additions and 17082 deletions
@@ -21,7 +21,7 @@
 //!
 //! ## Overview
 //!
-//! It does this by wrapping an existing [`SignedExtension`] implementation (e.g.
+//! It does this by wrapping an existing [`TransactionExtension`] implementation (e.g.
 //! [`pallet-transaction-payment`]) and checking if the dispatchable is feeless before applying the
 //! wrapped extension. If the dispatchable is indeed feeless, the extension is skipped and a custom
 //! event is emitted instead. Otherwise, the extension is applied as usual.
@@ -31,7 +31,8 @@
 //!
 //! This pallet wraps an existing transaction payment pallet. This means you should both pallets
 //! in your `construct_runtime` macro and include this pallet's
-//! [`SignedExtension`] ([`SkipCheckIfFeeless`]) that would accept the existing one as an argument.
+//! [`TransactionExtension`] ([`SkipCheckIfFeeless`]) that would accept the existing one as an
+//! argument.

 #![cfg_attr(not(feature = "std"), no_std)]

@@ -42,7 +43,10 @@ use frame_support::{
 };
 use scale_info::{StaticTypeInfo, TypeInfo};
 use sp_runtime::{
-	traits::{DispatchInfoOf, PostDispatchInfoOf, SignedExtension},
+	traits::{
+		DispatchInfoOf, OriginOf, PostDispatchInfoOf, TransactionExtension,
+		TransactionExtensionBase, ValidateResult,
+	},
 	transaction_validity::TransactionValidityError,
 };

@@ -70,11 +74,11 @@ pub mod pallet {
 	#[pallet::generate_deposit(pub(super) fn deposit_event)]
 	pub enum Event<T: Config> {
 		/// A transaction fee was skipped.
-		FeeSkipped { who: T::AccountId },
+		FeeSkipped { origin: <T::RuntimeOrigin as OriginTrait>::PalletsOrigin },
 	}
 }

-/// A [`SignedExtension`] that skips the wrapped extension if the dispatchable is feeless.
+/// A [`TransactionExtension`] that skips the wrapped extension if the dispatchable is feeless.
 #[derive(Encode, Decode, Clone, Eq, PartialEq)]
 pub struct SkipCheckIfFeeless<T, S>(pub S, sp_std::marker::PhantomData<T>);

@@ -103,53 +107,96 @@ impl<T, S> From<S> for SkipCheckIfFeeless<T, S> {
 	}
 }

-impl<T: Config + Send + Sync, S: SignedExtension<AccountId = T::AccountId>> SignedExtension
+pub enum Intermediate<T, O> {
+	/// The wrapped extension should be applied.
+	Apply(T),
+	/// The wrapped extension should be skipped.
+	Skip(O),
+}
+use Intermediate::*;
+
+impl<T: Config + Send + Sync, S: TransactionExtensionBase> TransactionExtensionBase
 	for SkipCheckIfFeeless<T, S>
-where
-	S::Call: CheckIfFeeless<Origin = frame_system::pallet_prelude::OriginFor<T>>,
 {
-	type AccountId = T::AccountId;
-	type Call = S::Call;
-	type AdditionalSigned = S::AdditionalSigned;
-	type Pre = (Self::AccountId, Option<<S as SignedExtension>::Pre>);
 	// From the outside this extension should be "invisible", because it just extends the wrapped
 	// extension with an extra check in `pre_dispatch` and `post_dispatch`. Thus, we should forward
 	// the identifier of the wrapped extension to let wallets see this extension as it would only be
 	// the wrapped extension itself.
 	const IDENTIFIER: &'static str = S::IDENTIFIER;
+	type Implicit = S::Implicit;

-	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		self.0.additional_signed()
+	fn implicit(&self) -> Result<Self::Implicit, TransactionValidityError> {
+		self.0.implicit()
 	}

-	fn pre_dispatch(
-		self,
-		who: &Self::AccountId,
-		call: &Self::Call,
-		info: &DispatchInfoOf<Self::Call>,
+	fn weight(&self) -> frame_support::weights::Weight {
+		self.0.weight()
+	}
+}
+
+impl<T: Config + Send + Sync, Context, S: TransactionExtension<T::RuntimeCall, Context>>
+	TransactionExtension<T::RuntimeCall, Context> for SkipCheckIfFeeless<T, S>
+where
+	T::RuntimeCall: CheckIfFeeless<Origin = frame_system::pallet_prelude::OriginFor<T>>,
+{
+	type Val = Intermediate<S::Val, <OriginOf<T::RuntimeCall> as OriginTrait>::PalletsOrigin>;
+	type Pre = Intermediate<S::Pre, <OriginOf<T::RuntimeCall> as OriginTrait>::PalletsOrigin>;
+
+	fn validate(
+		&self,
+		origin: OriginOf<T::RuntimeCall>,
+		call: &T::RuntimeCall,
+		info: &DispatchInfoOf<T::RuntimeCall>,
 		len: usize,
-	) -> Result<Self::Pre, TransactionValidityError> {
-		if call.is_feeless(&<T as frame_system::Config>::RuntimeOrigin::signed(who.clone())) {
-			Ok((who.clone(), None))
+		context: &mut Context,
+		self_implicit: S::Implicit,
+		inherited_implication: &impl Encode,
+	) -> ValidateResult<Self::Val, T::RuntimeCall> {
+		if call.is_feeless(&origin) {
+			Ok((Default::default(), Skip(origin.caller().clone()), origin))
 		} else {
-			Ok((who.clone(), Some(self.0.pre_dispatch(who, call, info, len)?)))
+			let (x, y, z) = self.0.validate(
+				origin,
+				call,
+				info,
+				len,
+				context,
+				self_implicit,
+				inherited_implication,
+			)?;
+			Ok((x, Apply(y), z))
+		}
+	}
+
+	fn prepare(
+		self,
+		val: Self::Val,
+		origin: &OriginOf<T::RuntimeCall>,
+		call: &T::RuntimeCall,
+		info: &DispatchInfoOf<T::RuntimeCall>,
+		len: usize,
+		context: &Context,
+	) -> Result<Self::Pre, TransactionValidityError> {
+		match val {
+			Apply(val) => self.0.prepare(val, origin, call, info, len, context).map(Apply),
+			Skip(origin) => Ok(Skip(origin)),
 		}
 	}

 	fn post_dispatch(
-		pre: Option<Self::Pre>,
-		info: &DispatchInfoOf<Self::Call>,
-		post_info: &PostDispatchInfoOf<Self::Call>,
+		pre: Self::Pre,
+		info: &DispatchInfoOf<T::RuntimeCall>,
+		post_info: &PostDispatchInfoOf<T::RuntimeCall>,
 		len: usize,
 		result: &DispatchResult,
+		context: &Context,
 	) -> Result<(), TransactionValidityError> {
-		if let Some(pre) = pre {
-			if let Some(pre) = pre.1 {
-				S::post_dispatch(Some(pre), info, post_info, len, result)?;
-			} else {
-				Pallet::<T>::deposit_event(Event::<T>::FeeSkipped { who: pre.0 });
-			}
+		match pre {
+			Apply(pre) => S::post_dispatch(pre, info, post_info, len, result, context),
+			Skip(origin) => {
+				Pallet::<T>::deposit_event(Event::<T>::FeeSkipped { origin });
+				Ok(())
+			},
 		}
-		Ok(())
 	}
 }
@@ -18,9 +18,12 @@ use crate as pallet_skip_feeless_payment;

 use frame_support::{derive_impl, parameter_types};
 use frame_system as system;
+use sp_runtime::{
+	impl_tx_ext_default,
+	traits::{OriginOf, TransactionExtension},
+};

 type Block = frame_system::mocking::MockBlock<Runtime>;
-type AccountId = u64;

 #[derive_impl(frame_system::config_preludes::TestDefaultConfig as frame_system::DefaultConfig)]
 impl frame_system::Config for Runtime {
@@ -38,21 +41,22 @@ parameter_types! {
 #[derive(Clone, Eq, PartialEq, Debug, Encode, Decode, TypeInfo)]
 pub struct DummyExtension;

-impl SignedExtension for DummyExtension {
-	type AccountId = AccountId;
-	type Call = RuntimeCall;
-	type AdditionalSigned = ();
-	type Pre = ();
+impl TransactionExtensionBase for DummyExtension {
 	const IDENTIFIER: &'static str = "DummyExtension";
-	fn additional_signed(&self) -> sp_std::result::Result<(), TransactionValidityError> {
-		Ok(())
-	}
-	fn pre_dispatch(
+	type Implicit = ();
+}
+impl<C> TransactionExtension<RuntimeCall, C> for DummyExtension {
+	type Val = ();
+	type Pre = ();
+	impl_tx_ext_default!(RuntimeCall; C; validate);
+	fn prepare(
 		self,
-		_who: &Self::AccountId,
-		_call: &Self::Call,
-		_info: &DispatchInfoOf<Self::Call>,
+		_val: Self::Val,
+		_origin: &OriginOf<RuntimeCall>,
+		_call: &RuntimeCall,
+		_info: &DispatchInfoOf<RuntimeCall>,
 		_len: usize,
+		_context: &C,
 	) -> Result<Self::Pre, TransactionValidityError> {
 		PreDispatchCount::mutate(|c| *c += 1);
 		Ok(())
@@ -16,18 +16,19 @@
 use super::*;
 use crate::mock::{pallet_dummy::Call, DummyExtension, PreDispatchCount, Runtime, RuntimeCall};
 use frame_support::dispatch::DispatchInfo;
+use sp_runtime::traits::DispatchTransaction;

 #[test]
 fn skip_feeless_payment_works() {
 	let call = RuntimeCall::DummyPallet(Call::<Runtime>::aux { data: 1 });
 	SkipCheckIfFeeless::<Runtime, DummyExtension>::from(DummyExtension)
-		.pre_dispatch(&0, &call, &DispatchInfo::default(), 0)
+		.validate_and_prepare(Some(0).into(), &call, &DispatchInfo::default(), 0)
 		.unwrap();
 	assert_eq!(PreDispatchCount::get(), 1);

 	let call = RuntimeCall::DummyPallet(Call::<Runtime>::aux { data: 0 });
 	SkipCheckIfFeeless::<Runtime, DummyExtension>::from(DummyExtension)
-		.pre_dispatch(&0, &call, &DispatchInfo::default(), 0)
+		.validate_and_prepare(Some(0).into(), &call, &DispatchInfo::default(), 0)
 		.unwrap();
 	assert_eq!(PreDispatchCount::get(), 1);
 }