Merge #19215: psbt: Include and allow both non_witness_utxo and witness_utxo for segwit inputs

84d295e51341a126a6c3cbeea7a8caa04c7b5bc3 tests: Check that segwit inputs in psbt have both UTXO types (Andrew Chow)
46004790588c24174a0bec49b540d158ce163ffd psbt: always put a non_witness_utxo and don't remove it (Andrew Chow)
5279d8bc07d601fe6a67ad665fbc7591fe73c7de psbt: Allow both non_witness_utxo and witness_utxo (Andrew Chow)
72f6bec1da198764d4648a10a61c485e7ab65e9e rpc: show both UTXOs in decodepsbt (Andrew Chow)

Pull request description:

  Due to recent changes to hardware wallets, the full previous transaction will need to be provided for segwit inputs. Since some software may be checking for the existence of a `witness_utxo` to determine whether to produce a segwit signature, we keep that field to ease the transition.

  Because all of the sanity checks implemented by the `IsSane` functions were related to having mixed segwit and non-segwit data in a PSBT, those functions are removed as those checks are no longer proper.

  Some tests are updated/removed to accommodate this and a simple test added to check that both UTXOs are being added to segwit inputs.

  As discussed in the wallet IRC meeting, our own signer will not require `non_witness_utxo` for segwit inputs.

ACKs for top commit:
  Sjors:
    utACK 84d295e51341a126a6c3cbeea7a8caa04c7b5bc3 (didn't retest compared to 836d6fc, but fortunately HWI's CI tracks our master branch, with a bunch of hardware wallet simulators)
  ryanofsky:
    Code review re-ACK 84d295e51341a126a6c3cbeea7a8caa04c7b5bc3. No changes since last review, but now I understand the context better. I think it would good to improve the comments as suggested https://github.com/bitcoin/bitcoin/pull/19215#discussion_r447889473 and maybe refer to
  meshcollider:
    utACK 84d295e51341a126a6c3cbeea7a8caa04c7b5bc3

Tree-SHA512: ccc1fd3c16ac3859f5aca4fa489bd40f68be0b81bbdc4dd51188bbf28827a8642dc8b605a37318e5f16cf40f1c4910052dace2f27eca21bb58435f02a443e940

3 files changed, 2 insertions, 17 deletions

diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index 3cc2611524..38d94335a3 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -597,11 +597,6 @@ TransactionError LegacyScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psb
             continue;
         }
 
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            return TransactionError::INVALID_PSBT;
-        }
-
         // Get the Sighash type
         if (sign && input.sighash_type > 0 && input.sighash_type != sighash_type) {
             return TransactionError::SIGHASH_MISMATCH;
@@ -2086,11 +2081,6 @@ TransactionError DescriptorScriptPubKeyMan::FillPSBT(PartiallySignedTransaction&
             continue;
         }
 
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            return TransactionError::INVALID_PSBT;
-        }
-
         // Get the Sighash type
         if (sign && input.sighash_type > 0 && input.sighash_type != sighash_type) {
             return TransactionError::SIGHASH_MISMATCH;
diff --git a/src/wallet/test/psbt_wallet_tests.cpp b/src/wallet/test/psbt_wallet_tests.cpp
index 3f85a48ff3..ce7e661b67 100644
--- a/src/wallet/test/psbt_wallet_tests.cpp
+++ b/src/wallet/test/psbt_wallet_tests.cpp
@@ -64,7 +64,7 @@ BOOST_AUTO_TEST_CASE(psbt_updater_test)
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
     ssTx << psbtx;
     std::string final_hex = HexStr(ssTx);
-    BOOST_CHECK_EQUAL(final_hex, "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");
+    BOOST_CHECK_EQUAL(final_hex, "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");
 
     // Mutate the transaction so that one of the inputs is invalid
     psbtx.tx->vin[0].prevout.n = 2;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 19acfa3322..235b269805 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -2507,13 +2507,8 @@ TransactionError CWallet::FillPSBT(PartiallySignedTransaction& psbtx, bool& comp
             continue;
         }
 
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            return TransactionError::INVALID_PSBT;
-        }
-
         // If we have no utxo, grab it from the wallet.
-        if (!input.non_witness_utxo && input.witness_utxo.IsNull()) {
+        if (!input.non_witness_utxo) {
             const uint256& txhash = txin.prevout.hash;
             const auto it = mapWallet.find(txhash);
             if (it != mapWallet.end()) {