txsize now just counts the serialized bytes

shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/LedgerState.hs

@@ -66,7 +66,9 @@ module Shelley.Spec.Ledger.LedgerState
     nullWitHashes,
     diffWitHashes,
     minfee,
+    minfeeBound,
     txsize,
+    txsizeBound,
     produced,
     consumed,
     verifiedWits,
@@ -705,8 +707,13 @@ genesisState genDelegs0 utxo0 =
     dState = emptyDState {_genDelegs = GenDelegs genDelegs0}
 
 -- | Implementation of abstract transaction size
-txsize :: forall crypto. (Crypto crypto) => Tx crypto -> Integer
-txsize tx = numInputs * inputSize + numOutputs * outputSize + rest
+txsize :: Tx crypto -> Integer
+txsize = fromIntegral . BSL.length . txFullBytes
+
+-- | Convenience Function to bound the txsize function.
+-- | It can be helpful for coin selection.
+txsizeBound :: forall crypto. (Crypto crypto) => Tx crypto -> Integer
+txsizeBound tx = numInputs * inputSize + numOutputs * outputSize + rest
   where
     uint = 5
     smallArray = 1
@@ -723,9 +730,13 @@ txsize tx = numInputs * inputSize + numOutputs * outputSize + rest
     rest = fromIntegral $ BSL.length (txFullBytes tx) - extraSize txbody
 
 -- | Minimum fee calculation
-minfee :: forall crypto. (Crypto crypto) => PParams -> Tx crypto -> Coin
+minfee :: PParams -> Tx crypto -> Coin
 minfee pp tx = Coin $ fromIntegral (_minfeeA pp) * txsize tx + fromIntegral (_minfeeB pp)
 
+-- | Minimum fee bound using txsizeBound
+minfeeBound :: forall crypto. (Crypto crypto) => PParams -> Tx crypto -> Coin
+minfeeBound pp tx = Coin $ fromIntegral (_minfeeA pp) * txsizeBound tx + fromIntegral (_minfeeB pp)
+
 -- | Compute the lovelace which are created by the transaction
 produced ::
   (Crypto crypto) =>

shelley/chain-and-ledger/executable-spec/test/Test/Shelley/Spec/Ledger/Fees.hs

@@ -499,16 +499,16 @@ sizeTests :: TestTree
 sizeTests =
   testGroup
     "Fee Tests"
-    [ testCase "simple utxo" $ sizeTest p txSimpleUTxOBytes16 txSimpleUTxO 143,
-      testCase "multiple utxo" $ sizeTest p txMutiUTxOBytes16 txMutiUTxO 470,
-      testCase "register stake key" $ sizeTest p txRegisterStakeBytes16 txRegisterStake 158,
-      testCase "delegate stake key" $ sizeTest p txDelegateStakeBytes16 txDelegateStake 194,
-      testCase "deregister stake key" $ sizeTest p txDeregisterStakeBytes16 txDeregisterStake 158,
-      testCase "register stake pool" $ sizeTest p txRegisterPoolBytes16 txRegisterPool 220,
-      testCase "retire stake pool" $ sizeTest p txRetirePoolBytes16 txRetirePool 157,
-      testCase "metadata" $ sizeTest p txWithMDBytes16 txWithMD 162,
-      testCase "multisig" $ sizeTest p txWithMultiSigBytes16 (txWithMultiSig p) 209,
-      testCase "reward withdrawal" $ sizeTest p txWithWithdrawalBytes16 txWithWithdrawal 184
+    [ testCase "simple utxo" $ sizeTest p txSimpleUTxOBytes16 txSimpleUTxO 73,
+      testCase "multiple utxo" $ sizeTest p txMutiUTxOBytes16 txMutiUTxO 194,
+      testCase "register stake key" $ sizeTest p txRegisterStakeBytes16 txRegisterStake 88,
+      testCase "delegate stake key" $ sizeTest p txDelegateStakeBytes16 txDelegateStake 124,
+      testCase "deregister stake key" $ sizeTest p txDeregisterStakeBytes16 txDeregisterStake 88,
+      testCase "register stake pool" $ sizeTest p txRegisterPoolBytes16 txRegisterPool 150,
+      testCase "retire stake pool" $ sizeTest p txRetirePoolBytes16 txRetirePool 87,
+      testCase "metadata" $ sizeTest p txWithMDBytes16 txWithMD 92,
+      testCase "multisig" $ sizeTest p txWithMultiSigBytes16 (txWithMultiSig p) 139,
+      testCase "reward withdrawal" $ sizeTest p txWithWithdrawalBytes16 txWithWithdrawal 114
     ]
   where
     p :: Proxy ShortHash

shelley/chain-and-ledger/executable-spec/test/Test/Shelley/Spec/Ledger/Generator/Utxo.hs

@@ -38,7 +38,7 @@ import Shelley.Spec.Ledger.Credential
   )
 import Shelley.Spec.Ledger.Keys (Hash, KeyRole (..), asWitness)
 import Shelley.Spec.Ledger.LedgerState
-  ( minfee,
+  ( minfeeBound,
     _dstate,
     _ptrs,
     _rewards,
@@ -222,7 +222,7 @@ genTx
           let metadata = SNothing -- TODO generate metadata
 
           -- calculate real fees of witnesses transaction
-          let minimalFees = minfee pparams (Tx txBody wits metadata)
+          let minimalFees = minfeeBound pparams (Tx txBody wits metadata)
 
           -- discard generated transaction if the balance cannot cover the fees
           if minimalFees > balance_

shelley/chain-and-ledger/executable-spec/test/Test/Shelley/Spec/Ledger/Rules/ClassifyTraces.hs

@@ -53,7 +53,7 @@ import Shelley.Spec.Ledger.Delegation.Certificates
     isRetirePool,
     isTreasuryMIRCert,
   )
-import Shelley.Spec.Ledger.LedgerState (txsize)
+import Shelley.Spec.Ledger.LedgerState (txsizeBound)
 import Shelley.Spec.Ledger.PParams
   ( PParamsUpdate,
     pattern ProposedPPUpdates,
@@ -332,7 +332,7 @@ propAbstractSizeBoundsBytes = property $ do
   forAllTraceFromInitState @(LEDGER ShortHash) testGlobals tl (genEnv p) genesisLedgerState $ \tr -> do
     let txs :: [Tx ShortHash]
         txs = traceSignals OldestFirst tr
-    all (\tx -> txsize tx >= numBytes tx) txs
+    all (\tx -> txsizeBound tx >= numBytes tx) txs
   where
     p :: Proxy ShortHash
     p = Proxy
@@ -349,7 +349,7 @@ propAbstractSizeNotTooBig = property $ do
       -- an acceptableMagnitude of three, though.
       acceptableMagnitude = (3 :: Integer)
       numBytes = toInteger . BS.length . serialize'
-      notTooBig txb = txsize txb <= acceptableMagnitude * numBytes txb
+      notTooBig txb = txsizeBound txb <= acceptableMagnitude * numBytes txb
   forAllTraceFromInitState @(LEDGER ShortHash) testGlobals tl (genEnv p) genesisLedgerState $ \tr -> do
     let txs :: [Tx ShortHash]
         txs = traceSignals OldestFirst tr

shelley/chain-and-ledger/executable-spec/test/Test/Shelley/Spec/Ledger/UnitTests.hs

@@ -515,7 +515,7 @@ testEmptyInputSet =
 testFeeTooSmall :: Assertion
 testFeeTooSmall =
   testInvalidTx
-    [UtxowFailure (UtxoFailure (FeeTooSmallUTxO (Coin 210) (Coin 1)))]
+    [UtxowFailure (UtxoFailure (FeeTooSmallUTxO (Coin 98) (Coin 1)))]
     $ aliceGivesBobLovelace
       AliceToBob
         { input = (TxIn genesisId 0),

shelley/chain-and-ledger/formal-spec/txsize.tex

@@ -2,48 +2,6 @@ \section{Implementation of \fun{txSize}}
 \label{sec:txSize}
 
 The minimum fee calculation in Figure~\ref{fig:defs:protocol-parameters-helpers}
-depends on an abstract $\fun{txSize}$ function, which we describe here.
-
-We define $\fun{txSize}$ as:
-$$\fun{txSize}~tx~=~\var{numInputs} \cdot 40 + \var{numOutputs} \cdot 65 + \var{rest},$$
-where
-\begin{itemize}
-  \item $\var{numInputs}$ is the number of transaction inputs in $\var{tx}$,
-  \item $\var{numOutputs}$ is the number of transaction outputs in $\var{tx}$,
-  \item $\var{tx'}$ is identical to $\var{tx}$, except that it has
-    \begin{itemize}
-      \item no inputs,
-      \item no outputs,
-      \item a fee of zero
-    \end{itemize}
-  \item $\var{rest}$ is the number of serialized bytes in $\var{tx'}$,
-    as defined in Appendix~\ref{sec:cddl},
-\end{itemize}
-
-
-We now justify this calculation.
-Using the number of bytes in the serialized transaction is problematic for a couple of reasons.
-First, the fee is listed in the transaction, so there is a circularity problem.
-Second, algorithms implementing coin selection
-(choosing which unspent transaction outputs to consume)
-would have to make heavy use of serialization.
-Besides these two issues, however, the number of serialized bytes
-does exactly what we want.
-
-Therefore we calculate the transaction size by first computing
-the number of bytes in a modifed version of the transaction
-that has no inputs, no outputs, and has a fee of zero,
-and then we adjust accordingly by the number of inputs and outputs.
-
-As given by the CDDL spec in Appendix~\ref{sec:cddl},
-a transaction input is serialized as:
-\begin{lstlisting}[backgroundcolor = \color{lightgray}]
-transaction_input = [ transaction_id : $hash32 , index : uint ]
-\end{lstlisting}
-which is bounded by 40 bytes.
-
-Similarly, a transaction output is serialized as:
-\begin{lstlisting}[backgroundcolor = \color{lightgray}]
-transaction_output = [address, amount : uint]
-\end{lstlisting}
-which is bounded by 65 bytes.
+depends on an abstract $\fun{txSize}$ function.
+We have implemented $\fun{txSize}$ as the number of bytes in the CBOR serialization
+of the transaction, as defined in Appendix~\ref{sec:cddl}.