Merge bitcoin/bitcoin#32859: functional test: correctly detect nonstd TRUC tx vsize in feature_taproot

f0524cd functional test: correctly detect nonstd TRUC tx vsize in feature_taproot (Greg Sanders)

Pull request description:

  Resolves bitcoin/bitcoin#32841 (comment)

ACKs for top commit:
  davidgumberg:
    utACK bitcoin/bitcoin@f0524cd
  achow101:
    ACK f0524cd
  darosior:
    utACK f0524cd
  w0xlt:
    ACK bitcoin/bitcoin@f0524cd

Tree-SHA512: b803c94f7a683b51bab88ae788384ff484a3e6597153bf022263bbc9531dd3faebb7832db26f2b8b4c0d0337c59991d0beca167def5aebe3e9a5d8a9bfdaaba5

Author: achow101

test/functional/feature_taproot.py

@@ -644,6 +644,7 @@ def byte_popper(expr):
 
 TX_MAX_STANDARD_VERSION = 3
 TX_STANDARD_VERSIONS = [1, 2, TX_MAX_STANDARD_VERSION]
+TRUC_MAX_VSIZE = 10000 # test doesn't cover in-mempool spends, so only this limit is hit
 
 # === Actual test cases ===
 
@@ -1538,7 +1539,9 @@ def test_spenders(self, node, spenders, input_counts):
                 is_standard_tx = (
                     fail_input is None  # Must be valid to be standard
                     and (all(utxo.spender.is_standard for utxo in input_utxos))  # All inputs must be standard
-                    and tx.version in TX_STANDARD_VERSIONS)  # The tx version must be standard
+                    and tx.version in TX_STANDARD_VERSIONS # The tx version must be standard
+                    and not (tx.version == 3 and tx.get_vsize() > TRUC_MAX_VSIZE)  # Topological standardness rules must be followed
+                )
                 msg = ','.join(utxo.spender.comment + ("*" if n == fail_input else "") for n, utxo in enumerate(input_utxos))
                 if is_standard_tx:
                     node.sendrawtransaction(tx.serialize().hex(), 0)