Merge #16525: Dump transaction version as an unsigned integer in RPC/TxToUniv

e80259f Additionally treat Tx.nVersion as unsigned in joinpsbts (Matt Corallo)
970de70 Dump transaction version as an unsigned integer in RPC/TxToUniv (Matt Corallo)

Pull request description:

  Consensus-wise we already treat it as an unsigned integer (the
  only rules around it are in CSV/locktime handling), but changing
  the underlying data type means touching consensus code for a
  simple cleanup change, which isn't really worth it.

  See-also, rust-bitcoin/rust-bitcoin#299

ACKs for top commit:
  sipa:
    ACK e80259f
  practicalswift:
    ACK e80259f
  ajtowns:
    ACK e80259f code review -- checked all other uses of tx.nVersion treat it as unsigned (except for policy.cpp:IsStandard anyway), so looks good.
  naumenkogs:
    ACK e80259f

Tree-SHA512: 6760a2c77e24e9e1f79a336ca925f9bbca3a827ce02003c71d7f214b82ed3dea13fa7d9f87df9b9445cd58dff8b44a15571d821c876f22f8e5a372a014c9976b

Author: laanwj

doc/release-notes-16525.md

@@ -0,0 +1,9 @@
+RPC changes
+-----------
+
+Exposed transaction version numbers are now treated as unsigned 32-bit integers
+instead of signed 32-bit integers. This matches their treatment in consensus
+logic. Versions greater than 2 continue to be non-standard (matching previous
+behavior of smaller than 1 or greater than 2 being non-standard). Note that
+this includes the joinpsbt command, which combines partially-signed
+transactions by selecting the highest version number.

src/core_write.cpp

@@ -179,7 +179,9 @@ void TxToUniv(const CTransaction& tx, const uint256& hashBlock, UniValue& entry,
 {
     entry.pushKV("txid", tx.GetHash().GetHex());
     entry.pushKV("hash", tx.GetWitnessHash().GetHex());
-    entry.pushKV("version", tx.nVersion);
+    // Transaction version is actually unsigned in consensus checks, just signed in memory,
+    // so cast to unsigned before giving it to the user.
+    entry.pushKV("version", static_cast<int64_t>(static_cast<uint32_t>(tx.nVersion)));
     entry.pushKV("size", (int)::GetSerializeSize(tx, PROTOCOL_VERSION));
     entry.pushKV("vsize", (GetTransactionWeight(tx) + WITNESS_SCALE_FACTOR - 1) / WITNESS_SCALE_FACTOR);
     entry.pushKV("weight", GetTransactionWeight(tx));

src/rpc/rawtransaction.cpp

@@ -1632,7 +1632,7 @@ UniValue joinpsbts(const JSONRPCRequest& request)
         throw JSONRPCError(RPC_INVALID_PARAMETER, "At least two PSBTs are required to join PSBTs.");
     }
 
-    int32_t best_version = 1;
+    uint32_t best_version = 1;
     uint32_t best_locktime = 0xffffffff;
     for (unsigned int i = 0; i < txs.size(); ++i) {
         PartiallySignedTransaction psbtx;
@@ -1642,8 +1642,8 @@ UniValue joinpsbts(const JSONRPCRequest& request)
         }
         psbtxs.push_back(psbtx);
         // Choose the highest version number
-        if (psbtx.tx->nVersion > best_version) {
-            best_version = psbtx.tx->nVersion;
+        if (static_cast<uint32_t>(psbtx.tx->nVersion) > best_version) {
+            best_version = static_cast<uint32_t>(psbtx.tx->nVersion);
         }
         // Choose the lowest lock time
         if (psbtx.tx->nLockTime < best_locktime) {
@@ -1654,7 +1654,7 @@ UniValue joinpsbts(const JSONRPCRequest& request)
     // Create a blank psbt where everything will be added
     PartiallySignedTransaction merged_psbt;
     merged_psbt.tx = CMutableTransaction();
-    merged_psbt.tx->nVersion = best_version;
+    merged_psbt.tx->nVersion = static_cast<int32_t>(best_version);
     merged_psbt.tx->nLockTime = best_locktime;
 
     // Merge

test/functional/rpc_rawtransaction.py

@@ -424,11 +424,12 @@ def run_test(self):
         ####################################
 
         # Test the minimum transaction version number that fits in a signed 32-bit integer.
+        # As transaction version is unsigned, this should convert to its unsigned equivalent.
         tx = CTransaction()
         tx.nVersion = -0x80000000
         rawtx = ToHex(tx)
         decrawtx = self.nodes[0].decoderawtransaction(rawtx)
-        assert_equal(decrawtx['version'], -0x80000000)
+        assert_equal(decrawtx['version'], 0x80000000)
 
         # Test the maximum transaction version number that fits in a signed 32-bit integer.
         tx = CTransaction()