wallet: skip R-value grinding for external signers

When producing a dummy signature for the purpose of estimating the transaction fee, do not assume an external signer performs R-value grinding on the signature.

In particular, this avoids a scenario where the fee rate is 1 sat / vbyte and a transaction with a 72 byte signature is not accepted into our mempool.

This commit also  drops the nullptr default for CCoinControl arguments for functions that it touches. This is because having a boolean argument right next to an optional pointer is error prone.

Co-Authored-By: S3RK <1466284+S3RK@users.noreply.github.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/wallet/spend.h b/src/wallet/spend.h
index d8da556d29..ad122b7ef3 100644
--- a/src/wallet/spend.h
+++ b/src/wallet/spend.h
@@ -17,8 +17,8 @@
 namespace wallet {
 /** Get the marginal bytes if spending the specified output from this transaction.
  * Use CoinControl to determine whether to expect signature grinding when calculating the size of the input spend. */
-int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet, const CCoinControl* coin_control = nullptr);
-int CalculateMaximumSignedInputSize(const CTxOut& txout, const COutPoint outpoint, const SigningProvider* pwallet, const CCoinControl* coin_control = nullptr);
+int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet, const CCoinControl* coin_control);
+int CalculateMaximumSignedInputSize(const CTxOut& txout, const COutPoint outpoint, const SigningProvider* pwallet, bool can_grind_r, const CCoinControl* coin_control);
 struct TxSize {
     int64_t vsize{-1};
     int64_t weight{-1};