Simplify arguments to SignPSBTInput

Remove redundant arguments to SignPSBTInput -- since it needs several
bits of the PartiallySignedTransaction, pass in a reference instead of
doing it piecemeal. This saves us having to pass in both a PSBTInput and
its index, as well as having to pass in the CTransaction. Also avoid
redundantly passing the sighash_type, which is contained in the
PSBTInput already.

src/rpc/rawtransaction.cpp

@@ -1542,9 +1542,7 @@ UniValue finalizepsbt(const JSONRPCRequest& request)
     //   script.
     bool complete = true;
     for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
-        PSBTInput& input = psbtx.inputs.at(i);
-
-        complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, *psbtx.tx, input, i, SIGHASH_ALL);
+        complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, psbtx, i, SIGHASH_ALL);
     }
 
     UniValue result(UniValue::VOBJ);

src/script/sign.cpp

@@ -244,8 +244,11 @@ bool PSBTInputSigned(PSBTInput& input)
     return !input.final_script_sig.empty() || !input.final_script_witness.IsNull();
 }
 
-bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, int index, int sighash)
+bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash)
 {
+    PSBTInput& input = psbt.inputs.at(index);
+    const CMutableTransaction& tx = *psbt.tx;
+
     if (PSBTInputSigned(input)) {
         return true;
     }

src/script/sign.h

@@ -734,7 +734,7 @@ bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom,
 bool PSBTInputSigned(PSBTInput& input);
 
 /** Signs a PSBTInput, verifying that all provided data matches what is being signed. */
-bool SignPSBTInput(const SigningProvider& provider, const CMutableTransaction& tx, PSBTInput& input, int index, int sighash = SIGHASH_ALL);
+bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash = SIGHASH_ALL);
 
 /** Extract signature data from a transaction input, and insert it. */
 SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout);

src/wallet/rpcwallet.cpp

@@ -3760,7 +3760,7 @@ bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, int sig
             throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "Specified Sighash and sighash in PSBT do not match.");
         }
 
-        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), *psbtx.tx, input, i, sighash_type);
+        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), psbtx, i, sighash_type);
     }
 
     // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change

src/wallet/rpcwallet.h

@@ -30,5 +30,5 @@ bool EnsureWalletIsAvailable(CWallet *, bool avoidException);
 
 UniValue getaddressinfo(const JSONRPCRequest& request);
 UniValue signrawtransactionwithwallet(const JSONRPCRequest& request);
-bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, int sighash_type = 1, bool sign = true, bool bip32derivs = false);
+bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, int sighash_type = 1 /* SIGHASH_ALL */, bool sign = true, bool bip32derivs = false);
 #endif //BITCOIN_WALLET_RPCWALLET_H

src/wallet/test/psbt_wallet_tests.cpp

@@ -60,7 +60,7 @@ BOOST_AUTO_TEST_CASE(psbt_updater_test)
     ssData >> psbtx;
 
     // Fill transaction with our data
-    FillPSBT(&m_wallet, psbtx, 1, false, true);
+    FillPSBT(&m_wallet, psbtx, SIGHASH_ALL, false, true);
 
     // Get the final tx
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);