Update x/auth AnteHandler Spec (#9298)

* Update auth antehandler spec

* Update x/auth/spec/03_antehandlers.md

Co-authored-by: Ryan Christoffersen <12519942+ryanchrypto@users.noreply.github.com>

* Update x/auth/spec/03_antehandlers.md

Co-authored-by: Ryan Christoffersen <12519942+ryanchrypto@users.noreply.github.com>

* Update x/auth/spec/03_antehandlers.md

Co-authored-by: Ryan Christoffersen <12519942+ryanchrypto@users.noreply.github.com>

* Use 1 line

* Use backticks

* Use consistent tx naming

* Fix grammar

* Update module naming

* Update x/auth/spec/03_antehandlers.md

Co-authored-by: Tyler <48813565+technicallyty@users.noreply.github.com>

Co-authored-by: Tyler <48813565+technicallyty@users.noreply.github.com>
Co-authored-by: Ryan Christoffersen <12519942+ryanchrypto@users.noreply.github.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

x/auth/spec/03_antehandlers.md

@@ -4,41 +4,37 @@ order: 3
 
 # AnteHandlers
 
-## Handlers
-
-The auth module presently has no transaction handlers of its own, but does expose
-the special `AnteHandler`, used for performing basic validity checks on a transaction,
-such that it could be thrown out of the mempool. Note that the ante handler is called on
-`CheckTx`, but _also_ on `DeliverTx`, as Tendermint proposers presently have the ability
-to include in their proposed block transactions which fail `CheckTx`.
-
-### Ante Handler
-
-```go
-anteHandler(ak AccountKeeper, fck FeeCollectionKeeper, tx sdk.Tx)
- if !tx.(StdTx)
- fail with "not a StdTx"
-
- if isCheckTx and tx.Fee < config.SubjectiveMinimumFee
- fail with "insufficient fee for mempool inclusion"
-
- if tx.ValidateBasic() != nil
- fail with "tx failed ValidateBasic"
-
- if tx.Fee > 0
- account = GetAccount(tx.GetSigners()[0])
- coins := acount.GetCoins()
- if coins < tx.Fee
- fail with "insufficient fee to pay for transaction"
- account.SetCoins(coins - tx.Fee)
- fck.AddCollectedFees(tx.Fee)
-
- for index, signature in tx.GetSignatures()
- account = GetAccount(tx.GetSigners()[index])
- bytesToSign := StdSignBytes(chainID, acc.GetAccountNumber(),
- acc.GetSequence(), tx.Fee, tx.Msgs, tx.Memo)
- if !signature.Verify(bytesToSign)
- fail with "invalid signature"
-
- return
-```
+The `x/auth` module presently has no transaction handlers of its own, but does expose the special `AnteHandler`, used for performing basic validity checks on a transaction, such that it could be thrown out of the mempool.
+The `AnteHandler` can be seen as a set of decorators that check transactions within the current context, per [ADR 010](https://github.com/cosmos/cosmos-sdk/blob/v0.43.0-alpha1/docs/architecture/adr-010-modular-antehandler.md).
+
+Note that the `AnteHandler` is called on both `CheckTx` and `DeliverTx`, as Tendermint proposers presently have the ability to include in their proposed block transactions which fail `CheckTx`.
+
+## Decorators
+
+The auth module provides `AnteDecorator`s that are recursively chained together into a single `AnteHandler` in the following order:
+
+- `SetUpContextDecorator`: Sets the `GasMeter` in the `Context` and wraps the next `AnteHandler` with a defer clause to recover from any downstream `OutOfGas` panics in the `AnteHandler` chain to return an error with information on gas provided and gas used.
+
+- `RejectExtensionOptionsDecorator`: Rejects all extension options which can optionally be included in protobuf transactions.
+
+- `MempoolFeeDecorator`: Checks if the `tx` fee is above local mempool `minFee` parameter during `CheckTx`.
+
+- `ValidateBasicDecorator`: Calls `tx.ValidateBasic` and returns any non-nil error.
+
+- `TxTimeoutHeightDecorator`: Check for a `tx` height timeout.
+
+- `ValidateMemoDecorator`: Validates `tx` memo with application parameters and returns any non-nil error.
+
+- `ConsumeGasTxSizeDecorator`: Consumes gas proportional to the `tx` size based on application parameters.
+
+- `DeductFeeDecorator`: Deducts the `FeeAmount` from first signer of the `tx`. If the `x/feegrant` module is enabled and a fee granter is set, it will deduct fees from the fee granter account.
+
+- `SetPubKeyDecorator`: Sets the pubkey from a `tx`'s signers that does not already have its corresponding pubkey saved in the state machine and in the current context.
+
+- `ValidateSigCountDecorator`: Validates the number of signatures in `tx` based on app-parameters.
+
+- `SigGasConsumeDecorator`: Consumes parameter-defined amount of gas for each signature. This requires pubkeys to be set in context for all signers as part of `SetPubKeyDecorator`.
+
+- `SigVerificationDecorator`: Verifies all signatures are valid. This requires pubkeys to be set in context for all signers as part of `SetPubKeyDecorator`.
+
+- `IncrementSequenceDecorator`: Increments the account sequence for each signer to prevent replay attacks.