Move estimateSignedTxSize to separate module

[Anviking]

-- |
-- Copyright: © 2023 IOHK, 2023 Cardano Foundation
-- License: Apache-2.0
--
-- Module for 'signTx' and signing-related utilities for balancing.
module Cardano.Wallet.Write.Tx.Sign
    (
    -- * Signing transactions
    -- TODO: Move signTx function here

    -- * Signing-related utilities required for balancing
      estimateSignedTxSize

    , KeyWitnessCount (..)
    , estimateKeyWitnessCount
    )
    where

Comments

• Depends on Move estimateTxSize etc to separate module #4036

Issue Number

ADP-3081

[jonathanknowles]

Just a thought: the estimateSignedTxSize and estimateKeyWitnessCount functions seem like ideal candidates to place within the Balance.SizeEstimation module, or a more general Balance.Estimation module, given that estimateKeyWitnessCount is not a size estimation, per se.

[Anviking]

I did very much want estimateKeyWitnessCount and signTx next to each other. estimateSignedTx might make sense in Write.Tx.SizeEstimation though. I'd suggest to revisit in another PR regardless.

[Anviking]

estimateSignedTx might make sense in Write.Tx.SizeEstimation though

Actually — no. estimateSignedTx is very different from the functions in the SizeEstimation module. It:

• is used by balanceTransaction, not coin selection
• doesn't actually estimate anything itself, it takes the previously estimated KeyWitnessCount as an argument
• is implemented using evaluateMinimumFee

So it should perhaps be called evaluateSignedTxSize instead.

[Anviking]

I did very much want estimateKeyWitnessCount and signTx next to each other.

The reason being that they should match. Or technically:

• signTx must never add more witnesses than estimateKeyWitnessCount estimated
• estimateKeyWitnessCount should never overestimate when transactions contain no native scripts

Related: https://cardanofoundation.atlassian.net/browse/ADP-2675