rpc: add `vsize_adjusted` and `vsize_bip141` field to mempool-related RPCs

diff --git a/src/rpc/mempool.cpp b/src/rpc/mempool.cpp
index 0358aeae..60783375 100644
--- a/src/rpc/mempool.cpp
+++ b/src/rpc/mempool.cpp
@@ -303,7 +303,11 @@ static RPCMethod testmempoolaccept()
                     {RPCResult::Type::STR, "package-error", /*optional=*/true, "Package validation error, if any (only possible if rawtxs had more than 1 transaction)."},
                     {RPCResult::Type::BOOL, "allowed", /*optional=*/true, "Whether this tx would be accepted to the mempool and pass client-specified maxfeerate. "
                                                        "If not present, the tx was not fully validated due to a failure in another tx in the list."},
-                    {RPCResult::Type::NUM, "vsize", /*optional=*/true, "Virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted (only present when 'allowed' is true)"},
+                    {RPCResult::Type::NUM, "vsize_adjusted", /*optional=*/true, "Maximum of sigop-adjusted size (-bytespersigop) and virtual transaction size as defined in BIP 141 (only present when 'allowed' is true)."},
+                    {RPCResult::Type::NUM, "vsize", /*optional=*/true, "(DEPRECATED) Was previously erroneously described as the BIP 141 vsize, but is actually sigops-adjusted vsize.\n"
+                                                                "Use vsize_bip141 to actually get that behavior or switch to the explicit vsize_adjusted for retained behavior."},
+                    {RPCResult::Type::NUM, "vsize_bip141", /*optional=*/true, "Virtual transaction size as defined in BIP 141.\n"
+                                                                       "This is different from actual serialized size for witness transactions as witness data is discounted (only present when 'allowed' is true)."},
                     {RPCResult::Type::OBJ, "fees", /*optional=*/true, "Transaction fees (only present if 'allowed' is true)",
                     {
                         {RPCResult::Type::STR_AMOUNT, "base", "transaction fee in " + CURRENCY_UNIT},
@@ -394,7 +398,9 @@ static RPCMethod testmempoolaccept()
                         // Only return the fee and vsize if the transaction would pass ATMP.
                         // These can be used to calculate the feerate.
                         result_inner.pushKV("allowed", true);
+                        result_inner.pushKV("vsize_adjusted", virtual_size);
                         result_inner.pushKV("vsize", virtual_size);
+                        result_inner.pushKV("vsize_bip141", GetVirtualTransactionSize(*tx));
                         UniValue fees(UniValue::VOBJ);
                         fees.pushKV("base", ValueFromAmount(fee));
                         fees.pushKV("effective-feerate", ValueFromAmount(tx_result.m_effective_feerate.value().GetFeePerK()));
@@ -443,7 +449,11 @@ static std::vector<RPCResult> ClusterDescription()
 static std::vector<RPCResult> MempoolEntryDescription()
 {
     std::vector<RPCResult> list = {
-        RPCResult{RPCResult::Type::NUM, "vsize", "virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
+        {RPCResult::Type::NUM, "vsize", /*optional=*/true, "(DEPRECATED) Was previously erroneously described as the BIP 141 vsize, but is actually sigops-adjusted vsize.\n"
+        "Use vsize_bip141 to actually get that behavior or switch to the explicit vsize_adjusted for retained behavior."},
+        {RPCResult::Type::NUM, "vsize_bip141", /*optional=*/true, "Virtual transaction size as defined in BIP 141.\n"
+        "This is different from actual serialized size for witness transactions as witness data is discounted (only present when 'allowed' is true)."},
+        {RPCResult::Type::NUM, "vsize_adjusted", /*optional=*/true, "Maximum of sigop-adjusted size (-bytespersigop) and virtual transaction size as defined in BIP 141 (only present when 'allowed' is true)."},
         RPCResult{RPCResult::Type::NUM, "weight", "transaction weight as defined in BIP 141."},
         RPCResult{RPCResult::Type::NUM_TIME, "time", "local time transaction entered pool in seconds since 1 Jan 1970 GMT"},
         RPCResult{RPCResult::Type::NUM, "height", "block height when transaction entered pool"},
@@ -527,7 +537,9 @@ static void entryToJSON(const CTxMemPool& pool, UniValue& info, const CTxMemPool
     auto [ancestor_count, ancestor_size, ancestor_fees] = pool.CalculateAncestorData(e);
     auto [descendant_count, descendant_size, descendant_fees] = pool.CalculateDescendantData(e);
 
+    info.pushKV("vsize_adjusted", e.GetTxSize());
     info.pushKV("vsize", e.GetTxSize());
+    info.pushKV("vsize_bip141", GetVirtualTransactionSize(e.GetTx()));
     info.pushKV("weight", e.GetTxWeight());
     info.pushKV("time", count_seconds(e.GetTime()));
     info.pushKV("height", e.GetHeight());
@@ -1229,7 +1241,8 @@ static std::vector<RPCResult> OrphanDescription()
         RPCResult{RPCResult::Type::STR_HEX, "txid", "The transaction hash in hex"},
         RPCResult{RPCResult::Type::STR_HEX, "wtxid", "The transaction witness hash in hex"},
         RPCResult{RPCResult::Type::NUM, "bytes", "The serialized transaction size in bytes"},
-        RPCResult{RPCResult::Type::NUM, "vsize", "The virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
+        RPCResult{RPCResult::Type::NUM, "vsize", "(DEPRECATED) use vsize_bip141 instead. The virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
+        RPCResult{RPCResult::Type::NUM, "vsize_bip141", "The virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
         RPCResult{RPCResult::Type::NUM, "weight", "The transaction weight as defined in BIP 141."},
         RPCResult{RPCResult::Type::ARR, "from", "",
         {
@@ -1245,6 +1258,7 @@ static UniValue OrphanToJSON(const node::TxOrphanage::OrphanInfo& orphan)
     o.pushKV("wtxid", orphan.tx->GetWitnessHash().ToString());
     o.pushKV("bytes", orphan.tx->ComputeTotalSize());
     o.pushKV("vsize", GetVirtualTransactionSize(*orphan.tx));
+    o.pushKV("vsize_bip141", GetVirtualTransactionSize(*orphan.tx));
     o.pushKV("weight", GetTransactionWeight(*orphan.tx));
     UniValue from(UniValue::VARR);
     for (const auto fromPeer: orphan.announcers) {
@@ -1358,7 +1372,10 @@ static RPCMethod submitpackage()
                     {RPCResult::Type::OBJ, "wtxid", "transaction wtxid", {
                         {RPCResult::Type::STR_HEX, "txid", "The transaction hash in hex"},
                         {RPCResult::Type::STR_HEX, "other-wtxid", /*optional=*/true, "The wtxid of a different transaction with the same txid but different witness found in the mempool. This means the submitted transaction was ignored."},
-                        {RPCResult::Type::NUM, "vsize", /*optional=*/true, "Sigops-adjusted virtual transaction size."},
+                        {RPCResult::Type::NUM, "vsize_adjusted", /*optional=*/true, "Maximum of sigop-adjusted size (-bytespersigop) and virtual transaction size as defined in BIP 141."},
+                        {RPCResult::Type::NUM, "vsize", /*optional=*/true, "(DEPRECATED) Was previously erroneously described as the BIP 141 vsize, but is actually sigops-adjusted vsize.\n"
+                                                                    "Use vsize_bip141 to actually get that behavior or switch to the explicit vsize_adjusted for retained behavior."},
+                        {RPCResult::Type::NUM, "vsize_bip141", /*optional=*/true, "Virtual transaction size as defined in BIP 141."},
                         {RPCResult::Type::OBJ, "fees", /*optional=*/true, "Transaction fees", {
                             {RPCResult::Type::STR_AMOUNT, "base", "transaction fee in " + CURRENCY_UNIT},
                             {RPCResult::Type::STR_AMOUNT, "effective-feerate", /*optional=*/true, "if the transaction was not already in the mempool, the effective feerate in " + CURRENCY_UNIT + " per KvB. For example, the package feerate and/or feerate with modified fees from prioritisetransaction."},
@@ -1506,7 +1523,9 @@ static RPCMethod submitpackage()
                     break;
                 case MempoolAcceptResult::ResultType::VALID:
                 case MempoolAcceptResult::ResultType::MEMPOOL_ENTRY:
+                    result_inner.pushKV("vsize_adjusted", it->second.m_vsize.value());
                     result_inner.pushKV("vsize", it->second.m_vsize.value());
+                    result_inner.pushKV("vsize_bip141", GetVirtualTransactionSize(*tx));
                     UniValue fees(UniValue::VOBJ);
                     fees.pushKV("base", ValueFromAmount(it->second.m_base_fees.value()));
                     if (tx_result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
diff --git a/test/functional/mempool_accept.py b/test/functional/mempool_accept.py
index 5893b1cc..b3e3749e 100755
--- a/test/functional/mempool_accept.py
+++ b/test/functional/mempool_accept.py
@@ -136,7 +136,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         raw_tx_0 = tx.serialize().hex()
         txid_0 = tx.txid_hex
         self.check_mempool_result(
-            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': fee}}],
+            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize_adjusted': tx.get_vsize(),  'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(),'fees': {'base': fee}}],
             rawtxs=[raw_tx_0],
         )
 
@@ -151,7 +151,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx = tx_from_hex(raw_tx_final)
         fee_expected = Decimal('50.0') - output_amount
         self.check_mempool_result(
-            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': fee_expected}}],
+            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize_adjusted': tx.get_vsize(), 'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), 'fees': {'base': fee_expected}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0,
         )
@@ -172,7 +172,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         raw_tx_0 = tx.serialize().hex()
         txid_0 = tx.txid_hex
         self.check_mempool_result(
-            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': (2 * fee)}}],
+            result_expected=[{'txid': txid_0, 'allowed': True, 'vsize_adjusted': tx.get_vsize(), 'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), 'fees': {'base': (2 * fee)}}],
             rawtxs=[raw_tx_0],
         )
         node.sendrawtransaction(hexstring=tx.serialize().hex(), maxfeerate=0)
@@ -218,7 +218,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         raw_tx_reference = tx.serialize().hex()
         # Reference tx should be valid on itself
         self.check_mempool_result(
-            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': { 'base': Decimal('0.1') - Decimal('0.05')}}],
+            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize_adjusted': tx.get_vsize(), 'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), 'fees': { 'base': Decimal('0.1') - Decimal('0.05')}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0,
         )
@@ -354,7 +354,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout.append(CTxOut(0, CScript([OP_RETURN, b'\xff' * 50000])))
 
         self.check_mempool_result(
-            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': {'base': Decimal('0.05')}}],
+            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize_adjusted': tx.get_vsize(), 'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), 'fees': {'base': Decimal('0.05')}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0
         )
@@ -366,7 +366,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'\xff'])
         tx.vout = [tx.vout[0]] * op_return_count
         self.check_mempool_result(
-            result_expected=[{"txid": tx.txid_hex, "allowed": True, "vsize": tx.get_vsize(), "fees": {"base": Decimal("0.05000026")}}],
+            result_expected=[{"txid": tx.txid_hex, "allowed": True, "vsize_adjusted": tx.get_vsize(), "vsize": tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), "fees": {"base": Decimal("0.05000026")}}],
             rawtxs=[tx.serialize().hex()],
         )
 
@@ -377,7 +377,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b"\xff" * (data_len)])
         assert_equal(tx.get_vsize(), int(MAX_STANDARD_TX_WEIGHT / 4))
         self.check_mempool_result(
-            result_expected=[{"txid": tx.txid_hex, "allowed": True, "vsize": tx.get_vsize(), "fees": {"base": Decimal("0.1") - Decimal("0.05")}}],
+            result_expected=[{"txid": tx.txid_hex, "allowed": True, "vsize_adjusted": tx.get_vsize(), "vsize": tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), "fees": {"base": Decimal("0.1") - Decimal("0.05")}}],
             rawtxs=[tx.serialize().hex()],
         )
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b"\xff" * (data_len + 1)])
@@ -430,7 +430,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         tx.vout[0] = CTxOut(COIN - 1000, DUMMY_MIN_OP_RETURN_SCRIPT)
         assert_equal(len(tx.serialize_without_witness()), MIN_STANDARD_TX_NONWITNESS_SIZE)
         self.check_mempool_result(
-            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize': tx.get_vsize(), 'fees': { 'base': Decimal('0.00001000')}}],
+            result_expected=[{'txid': tx.txid_hex, 'allowed': True, 'vsize_adjusted': tx.get_vsize(), 'vsize': tx.get_vsize(), 'vsize_bip141': tx.get_vsize(), 'fees': { 'base': Decimal('0.00001000')}}],
             rawtxs=[tx.serialize().hex()],
             maxfeerate=0,
         )
@@ -468,7 +468,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         assert_equal(anchor_spend.txid_hex, anchor_spend.wtxid_hex)
 
         self.check_mempool_result(
-            result_expected=[{'txid': anchor_spend.txid_hex, 'allowed': True, 'vsize': anchor_spend.get_vsize(), 'fees': { 'base': Decimal('0.00000700')}}],
+            result_expected=[{'txid': anchor_spend.txid_hex, 'allowed': True, 'vsize_adjusted': anchor_spend.get_vsize(), 'vsize': anchor_spend.get_vsize(), 'vsize_bip141': anchor_spend.get_vsize(), 'fees': { 'base': Decimal('0.00000700')}}],
             rawtxs=[anchor_spend.serialize().hex()],
             maxfeerate=0,
         )
@@ -503,7 +503,7 @@ class MempoolAcceptanceTest(BitcoinTestFramework):
         sign_input_legacy(tx_spend, 0, tx.vout[0].scriptPubKey, privkey, sighash_type=SIGHASH_ALL)
         tx_spend.vin[0].scriptSig = bytes(CScript([OP_0])) + tx_spend.vin[0].scriptSig
         self.check_mempool_result(
-            result_expected=[{'txid': tx_spend.txid_hex, 'allowed': True, 'vsize': tx_spend.get_vsize(), 'fees': { 'base': Decimal('0.00000700')}}],
+            result_expected=[{'txid': tx_spend.txid_hex, 'allowed': True, 'vsize_adjusted': tx_spend.get_vsize(), 'vsize': tx_spend.get_vsize(), 'vsize_bip141': tx_spend.get_vsize(), 'fees': { 'base': Decimal('0.00000700')}}],
             rawtxs=[tx_spend.serialize().hex()],
             maxfeerate=0,
         )
diff --git a/test/functional/mempool_sigoplimit.py b/test/functional/mempool_sigoplimit.py
index 823d7054..1ade8469 100755
--- a/test/functional/mempool_sigoplimit.py
+++ b/test/functional/mempool_sigoplimit.py
@@ -41,6 +41,7 @@ from test_framework.util import (
     assert_equal,
     assert_greater_than,
     assert_greater_than_or_equal,
+    assert_not_equal,
     assert_raises_rpc_error,
 )
 from test_framework.wallet import MiniWallet
@@ -98,14 +99,20 @@ class BytesPerSigOpTest(BitcoinTestFramework):
 
         res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
         assert_equal(res['allowed'], True)
+        assert_equal(sigop_equivalent_vsize, tx.get_vsize())
         assert_equal(res['vsize'], sigop_equivalent_vsize)
+        assert_equal(res['vsize_adjusted'], sigop_equivalent_vsize)
+        assert_equal(res['vsize_bip141'], tx.get_vsize())
 
         # increase the tx's vsize to be right above the sigop-limit equivalent size
         # => tx's vsize in mempool should also grow accordingly
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad+1)])
         res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
         assert_equal(res['allowed'], True)
+        assert_equal(sigop_equivalent_vsize + 1, tx.get_vsize())
         assert_equal(res['vsize'], sigop_equivalent_vsize+1)
+        assert_equal(res['vsize_adjusted'], sigop_equivalent_vsize + 1)
+        assert_equal(res['vsize_bip141'], tx.get_vsize())
 
         # decrease the tx's vsize to be right below the sigop-limit equivalent size
         # => tx's vsize in mempool should stick at the sigop-limit equivalent
@@ -114,7 +121,10 @@ class BytesPerSigOpTest(BitcoinTestFramework):
         tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad-1)])
         res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
         assert_equal(res['allowed'], True)
+        assert_not_equal(sigop_equivalent_vsize, tx.get_vsize())
         assert_equal(res['vsize'], sigop_equivalent_vsize)
+        assert_equal(res['vsize_adjusted'], sigop_equivalent_vsize)
+        assert_equal(res['vsize_bip141'], tx.get_vsize())
 
         # check that the ancestor and descendant size calculations in the mempool
         # also use the same max(sigop_equivalent_vsize, serialized_vsize) logic
@@ -166,7 +176,7 @@ class BytesPerSigOpTest(BitcoinTestFramework):
         parent_individual_testres = self.nodes[0].testmempoolaccept([tx_parent.serialize().hex()])[0]
         assert parent_individual_testres["allowed"]
         max_multisig_vsize = MAX_PUBKEYS_PER_MULTISIG * 5000
-        assert_equal(parent_individual_testres["vsize"], max_multisig_vsize)
+        assert_equal(parent_individual_testres["vsize_adjusted"], max_multisig_vsize)
 
         # But together, it's exceeding limits in the *package* context. If sigops adjusted vsize wasn't being checked
         # here, it would get further in validation and give too-large-cluster error instead.
diff --git a/test/functional/p2p_segwit.py b/test/functional/p2p_segwit.py
index 92ebe21a..6224e9c5 100755
--- a/test/functional/p2p_segwit.py
+++ b/test/functional/p2p_segwit.py
@@ -615,7 +615,9 @@ class SegWitTest(BitcoinTestFramework):
                     'txid': tx3.txid_hex,
                     'wtxid': tx3.wtxid_hex,
                     'allowed': True,
+                    'vsize_adjusted': tx3.get_vsize(),
                     'vsize': tx3.get_vsize(),
+                    'vsize_bip141': tx3.get_vsize(),
                     'fees': {
                         'base': Decimal('0.00001000'),
                     },
@@ -633,7 +635,9 @@ class SegWitTest(BitcoinTestFramework):
                     'txid': tx3.txid_hex,
                     'wtxid': tx3.wtxid_hex,
                     'allowed': True,
+                    'vsize_adjusted': tx3.get_vsize(),
                     'vsize': tx3.get_vsize(),
+                    'vsize_bip141': tx3.get_vsize(),
                     'fees': {
                         'base': Decimal('0.00011000'),
                     },
diff --git a/test/functional/rpc_packages.py b/test/functional/rpc_packages.py
index 12e08621..647d16df 100755
--- a/test/functional/rpc_packages.py
+++ b/test/functional/rpc_packages.py
@@ -302,6 +302,7 @@ class RPCPackagesTest(BitcoinTestFramework):
         assert_equal(testres_replaceable["wtxid"], replaceable_tx["wtxid"])
         assert testres_replaceable["allowed"]
         assert_equal(testres_replaceable["vsize"], replaceable_tx["tx"].get_vsize())
+        assert_equal(testres_replaceable["vsize_bip141"], replaceable_tx["tx"].get_vsize())
         assert_equal(testres_replaceable["fees"]["base"], fee)
         assert_fee_amount(fee, replaceable_tx["tx"].get_vsize(), testres_replaceable["fees"]["effective-feerate"])
         assert_equal(testres_replaceable["fees"]["effective-includes"], [replaceable_tx["wtxid"]])
@@ -339,9 +340,11 @@ class RPCPackagesTest(BitcoinTestFramework):
             # No "allowed" if the tx was already in the mempool
             if "allowed" in testres_tx and testres_tx["allowed"]:
                 assert_equal(submitres_tx["vsize"], testres_tx["vsize"])
+                assert_equal(submitres_tx["vsize_bip141"], testres_tx["vsize"])
                 assert_equal(submitres_tx["fees"]["base"], testres_tx["fees"]["base"])
             entry_info = node.getmempoolentry(submitres_tx["txid"])
             assert_equal(submitres_tx["vsize"], entry_info["vsize"])
+            assert_equal(submitres_tx["vsize_bip141"], entry_info["vsize"])
             assert_equal(submitres_tx["fees"]["base"], entry_info["fees"]["base"])
 
     def test_submit_child_with_parents(self, num_parents, partial_submit):
@@ -371,7 +374,9 @@ class RPCPackagesTest(BitcoinTestFramework):
             assert wtxid in submitpackage_result["tx-results"]
             tx_result = submitpackage_result["tx-results"][wtxid]
             assert_equal(tx_result["txid"], tx.txid_hex)
+            assert_equal(tx_result["vsize_adjusted"], tx.get_vsize())
             assert_equal(tx_result["vsize"], tx.get_vsize())
+            assert_equal(tx_result["vsize_bip141"], tx.get_vsize())
             assert_equal(tx_result["fees"]["base"], DEFAULT_FEE)
             if wtxid not in presubmitted_wtxids:
                 assert_fee_amount(DEFAULT_FEE, tx.get_vsize(), tx_result["fees"]["effective-feerate"])