Revert "FRAME: Create TransactionExtension as a replacement for SignedExtension (#2280)" (#3665)

This PR reverts #2280 which introduced `TransactionExtension` to replace
`SignedExtension`.

As a result of the discussion
[here](https://github.com/paritytech/polkadot-sdk/pull/3623#issuecomment-1986789700),
the changes will be reverted for now with plans to reintroduce the
concept in the future.

---------

Signed-off-by: georgepisaltu <george.pisaltu@parity.io>

substrate/primitives/runtime/src/generic/checked_extrinsic.rs

@@ -18,115 +18,81 @@
 //! Generic implementation of an extrinsic that has passed the verification
 //! stage.
 
-use codec::Encode;
-
 use crate::{
 	traits::{
-		self, transaction_extension::TransactionExtension, DispatchInfoOf, DispatchTransaction,
-		Dispatchable, MaybeDisplay, Member, PostDispatchInfoOf, ValidateUnsigned,
+		self, DispatchInfoOf, Dispatchable, MaybeDisplay, Member, PostDispatchInfoOf,
+		SignedExtension, ValidateUnsigned,
 	},
 	transaction_validity::{TransactionSource, TransactionValidity},
 };
 
-/// The kind of extrinsic this is, including any fields required of that kind. This is basically
-/// the full extrinsic except the `Call`.
-#[derive(PartialEq, Eq, Clone, sp_core::RuntimeDebug)]
-pub enum ExtrinsicFormat<AccountId, Extension> {
-	/// Extrinsic is bare; it must pass either the bare forms of `TransactionExtension` or
-	/// `ValidateUnsigned`, both deprecated, or alternatively a `ProvideInherent`.
-	Bare,
-	/// Extrinsic has a default `Origin` of `Signed(AccountId)` and must pass all
-	/// `TransactionExtension`s regular checks and includes all extension data.
-	Signed(AccountId, Extension),
-	/// Extrinsic has a default `Origin` of `None` and must pass all `TransactionExtension`s.
-	/// regular checks and includes all extension data.
-	General(Extension),
-}
-
-// TODO: Rename ValidateUnsigned to ValidateInherent
-// TODO: Consider changing ValidateInherent API to avoid need for duplicating validate
-//   code into pre_dispatch (rename that to `prepare`).
-// TODO: New extrinsic type corresponding to `ExtrinsicFormat::General`, which is
-//   unsigned but includes extension data.
-// TODO: Move usage of `signed` to `format`:
-// - Inherent instead of None.
-// - Signed(id, extension) instead of Some((id, extra)).
-// - Introduce General(extension) for one without a signature.
-
 /// Definition of something that the external world might want to say; its existence implies that it
 /// has been checked and is good, particularly with regards to the signature.
 ///
 /// This is typically passed into [`traits::Applyable::apply`], which should execute
 /// [`CheckedExtrinsic::function`], alongside all other bits and bobs.
 #[derive(PartialEq, Eq, Clone, sp_core::RuntimeDebug)]
-pub struct CheckedExtrinsic<AccountId, Call, Extension> {
+pub struct CheckedExtrinsic<AccountId, Call, Extra> {
 	/// Who this purports to be from and the number of extrinsics have come before
 	/// from the same signer, if anyone (note this is not a signature).
-	pub format: ExtrinsicFormat<AccountId, Extension>,
+	pub signed: Option<(AccountId, Extra)>,
 
 	/// The function that should be called.
 	pub function: Call,
 }
 
-impl<AccountId, Call, Extension, RuntimeOrigin> traits::Applyable
-	for CheckedExtrinsic<AccountId, Call, Extension>
+impl<AccountId, Call, Extra, RuntimeOrigin> traits::Applyable
+	for CheckedExtrinsic<AccountId, Call, Extra>
 where
 	AccountId: Member + MaybeDisplay,
-	Call: Member + Dispatchable<RuntimeOrigin = RuntimeOrigin> + Encode,
-	Extension: TransactionExtension<Call, ()>,
+	Call: Member + Dispatchable<RuntimeOrigin = RuntimeOrigin>,
+	Extra: SignedExtension<AccountId = AccountId, Call = Call>,
 	RuntimeOrigin: From<Option<AccountId>>,
 {
 	type Call = Call;
 
-	fn validate<I: ValidateUnsigned<Call = Self::Call>>(
+	fn validate<U: ValidateUnsigned<Call = Self::Call>>(
 		&self,
+		// TODO [#5006;ToDr] should source be passed to `SignedExtension`s?
+		// Perhaps a change for 2.0 to avoid breaking too much APIs?
 		source: TransactionSource,
 		info: &DispatchInfoOf<Self::Call>,
 		len: usize,
 	) -> TransactionValidity {
-		match self.format {
-			ExtrinsicFormat::Bare => {
-				let inherent_validation = I::validate_unsigned(source, &self.function)?;
-				#[allow(deprecated)]
-				let legacy_validation = Extension::validate_bare_compat(&self.function, info, len)?;
-				Ok(legacy_validation.combine_with(inherent_validation))
-			},
-			ExtrinsicFormat::Signed(ref signer, ref extension) => {
-				let origin = Some(signer.clone()).into();
-				extension.validate_only(origin, &self.function, info, len).map(|x| x.0)
-			},
-			ExtrinsicFormat::General(ref extension) =>
-				extension.validate_only(None.into(), &self.function, info, len).map(|x| x.0),
+		if let Some((ref id, ref extra)) = self.signed {
+			Extra::validate(extra, id, &self.function, info, len)
+		} else {
+			let valid = Extra::validate_unsigned(&self.function, info, len)?;
+			let unsigned_validation = U::validate_unsigned(source, &self.function)?;
+			Ok(valid.combine_with(unsigned_validation))
 		}
 	}
 
-	fn apply<I: ValidateUnsigned<Call = Self::Call>>(
+	fn apply<U: ValidateUnsigned<Call = Self::Call>>(
 		self,
 		info: &DispatchInfoOf<Self::Call>,
 		len: usize,
 	) -> crate::ApplyExtrinsicResultWithInfo<PostDispatchInfoOf<Self::Call>> {
-		match self.format {
-			ExtrinsicFormat::Bare => {
-				I::pre_dispatch(&self.function)?;
-				// TODO: Remove below once `pre_dispatch_unsigned` is removed from `LegacyExtension`
-				//   or `LegacyExtension` is removed.
-				#[allow(deprecated)]
-				Extension::validate_bare_compat(&self.function, info, len)?;
-				#[allow(deprecated)]
-				Extension::pre_dispatch_bare_compat(&self.function, info, len)?;
-				let res = self.function.dispatch(None.into());
-				let post_info = res.unwrap_or_else(|err| err.post_info);
-				let pd_res = res.map(|_| ()).map_err(|e| e.error);
-				// TODO: Remove below once `pre_dispatch_unsigned` is removed from `LegacyExtension`
-				//   or `LegacyExtension` is removed.
-				#[allow(deprecated)]
-				Extension::post_dispatch_bare_compat(info, &post_info, len, &pd_res)?;
-				Ok(res)
-			},
-			ExtrinsicFormat::Signed(signer, extension) =>
-				extension.dispatch_transaction(Some(signer).into(), self.function, info, len),
-			ExtrinsicFormat::General(extension) =>
-				extension.dispatch_transaction(None.into(), self.function, info, len),
-		}
+		let (maybe_who, maybe_pre) = if let Some((id, extra)) = self.signed {
+			let pre = Extra::pre_dispatch(extra, &id, &self.function, info, len)?;
+			(Some(id), Some(pre))
+		} else {
+			Extra::pre_dispatch_unsigned(&self.function, info, len)?;
+			U::pre_dispatch(&self.function)?;
+			(None, None)
+		};
+		let res = self.function.dispatch(RuntimeOrigin::from(maybe_who));
+		let post_info = match res {
+			Ok(info) => info,
+			Err(err) => err.post_info,
+		};
+		Extra::post_dispatch(
+			maybe_pre,
+			info,
+			&post_info,
+			len,
+			&res.map(|_| ()).map_err(|e| e.error),
+		)?;
+		Ok(res)
 	}
 }

substrate/primitives/runtime/src/generic/mod.rs

@@ -29,9 +29,9 @@ mod unchecked_extrinsic;
 
 pub use self::{
 	block::{Block, BlockId, SignedBlock},
-	checked_extrinsic::{CheckedExtrinsic, ExtrinsicFormat},
+	checked_extrinsic::CheckedExtrinsic,
 	digest::{Digest, DigestItem, DigestItemRef, OpaqueDigestItemId},
 	era::{Era, Phase},
 	header::Header,
-	unchecked_extrinsic::{Preamble, SignedPayload, UncheckedExtrinsic},
+	unchecked_extrinsic::{SignedPayload, UncheckedExtrinsic},
 };