Merge bitcoin/bitcoin#24941: test: MiniWallet: support skipping mempool checks (feature_fee_estimation.py performance fix)

a498acc test: MiniWallet: skip mempool check if `mempool_valid=False` (Sebastian Falbesoner)
01552e8 test: MiniWallet: always rehash after signing (P2PK mode) (Sebastian Falbesoner)

Pull request description:

  MiniWallet's core method for creating txs (`create_self_transfer`) right now always executes the `testmempoolaccept` RPC to check for mempool validity or invalidity. In some test cases where we use MiniWallet to create a huge number of transactions this can lead to performance issues, in particular feature_fee_estimation.py where the execution time after MiniWallet usage (PR #24817) doubled, see bitcoin/bitcoin#24828 (comment), bitcoin/bitcoin#24828 (comment). This PR mitigates this by skipping the mempool check if the parameter `mempool_valid` is set to `False`.

  As a preparatory commit, the test feature_csv_activation.py has to be adapted w.r.t. to rehashing of transactions, as we now hash all transactions immediately in `create_self_transfer` in order to get the txid (before we relied on the result of `testmempoolaccept`).

  On my machine, this decreases the execution time quite noticably:

  master branch:
  ```
  $ time ./test/functional/feature_fee_estimation.py
  real    3m20.771s
  user    2m52.360s
  sys     0m39.340s
  ```

  PR branch:
  ```
  $ time ./test/functional/feature_fee_estimation.py
  real    2m1.386s
  user    1m42.510s
  sys     0m22.980s
  ```

  Partly fixes #24828 (hopefully).

ACKs for top commit:
  danielabrozzoni:
    tACK a498acc

Tree-SHA512: f20c358ba42b2ded86175f46ff3ff9eaefb84175cbd1c2624f44904c8d8888e67ce64d6dcbb26aabbf07906e6f5bdea40353eba9ae668618cadcfc517ef7201b

Author: MacroFake

test/functional/feature_csv_activation.py

@@ -112,13 +112,15 @@ def create_bip112special(self, input, txversion):
         tx.nVersion = txversion
         self.miniwallet.sign_tx(tx)
         tx.vin[0].scriptSig = CScript([-1, OP_CHECKSEQUENCEVERIFY, OP_DROP] + list(CScript(tx.vin[0].scriptSig)))
+        tx.rehash()
         return tx
 
     def create_bip112emptystack(self, input, txversion):
         tx = self.create_self_transfer_from_utxo(input)
         tx.nVersion = txversion
         self.miniwallet.sign_tx(tx)
         tx.vin[0].scriptSig = CScript([OP_CHECKSEQUENCEVERIFY] + list(CScript(tx.vin[0].scriptSig)))
+        tx.rehash()
         return tx
 
     def send_generic_input_tx(self, coinbases):
@@ -136,7 +138,6 @@ def create_bip68txs(self, bip68inputs, txversion, locktime_delta=0):
             tx.nVersion = txversion
             tx.vin[0].nSequence = locktime + locktime_delta
             self.miniwallet.sign_tx(tx)
-            tx.rehash()
             txs.append({'tx': tx, 'sdf': sdf, 'stf': stf})
 
         return txs
@@ -339,20 +340,16 @@ def run_test(self):
         # BIP 113 tests should now fail regardless of version number if nLockTime isn't satisfied by new rules
         bip113tx_v1.nLockTime = self.last_block_time - 600 * 5  # = MTP of prior block (not <) but < time put on current block
         self.miniwallet.sign_tx(bip113tx_v1)
-        bip113tx_v1.rehash()
         bip113tx_v2.nLockTime = self.last_block_time - 600 * 5  # = MTP of prior block (not <) but < time put on current block
         self.miniwallet.sign_tx(bip113tx_v2)
-        bip113tx_v2.rehash()
         for bip113tx in [bip113tx_v1, bip113tx_v2]:
             self.send_blocks([self.create_test_block([bip113tx])], success=False, reject_reason='bad-txns-nonfinal')
 
         # BIP 113 tests should now pass if the locktime is < MTP
         bip113tx_v1.nLockTime = self.last_block_time - 600 * 5 - 1  # < MTP of prior block
         self.miniwallet.sign_tx(bip113tx_v1)
-        bip113tx_v1.rehash()
         bip113tx_v2.nLockTime = self.last_block_time - 600 * 5 - 1  # < MTP of prior block
         self.miniwallet.sign_tx(bip113tx_v2)
-        bip113tx_v2.rehash()
         for bip113tx in [bip113tx_v1, bip113tx_v2]:
             self.send_blocks([self.create_test_block([bip113tx])])
             self.nodes[0].invalidateblock(self.nodes[0].getbestblockhash())
@@ -477,7 +474,6 @@ def run_test(self):
         for tx in [tx['tx'] for tx in bip112txs_vary_OP_CSV_v2 if not tx['sdf'] and tx['stf']]:
             tx.vin[0].nSequence = BASE_RELATIVE_LOCKTIME | SEQ_TYPE_FLAG
             self.miniwallet.sign_tx(tx)
-            tx.rehash()
             time_txs.append(tx)
 
         self.send_blocks([self.create_test_block(time_txs)])

test/functional/test_framework/wallet.py

@@ -127,6 +127,7 @@ def sign_tx(self, tx, fixed_length=True):
             if not fixed_length:
                 break
         tx.vin[0].scriptSig = CScript([der_sig + bytes(bytearray([SIGHASH_ALL]))])
+        tx.rehash()
 
     def generate(self, num_blocks, **kwargs):
         """Generate blocks with coinbase outputs to the internal address, and append the outputs to the internal list"""
@@ -233,7 +234,8 @@ def create_self_transfer_multi(self, *, from_node, utxos_to_spend=None, num_outp
         return tx
 
     def create_self_transfer(self, *, fee_rate=Decimal("0.003"), from_node=None, utxo_to_spend=None, mempool_valid=True, locktime=0, sequence=0):
-        """Create and return a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed."""
+        """Create and return a tx with the specified fee_rate. Fee may be exact or at most one satoshi higher than needed.
+           Checking mempool validity via the testmempoolaccept RPC can be skipped by setting mempool_valid to False."""
         from_node = from_node or self._test_node
         utxo_to_spend = utxo_to_spend or self.get_utxo()
         if self._priv_key is None:
@@ -260,12 +262,13 @@ def create_self_transfer(self, *, fee_rate=Decimal("0.003"), from_node=None, utx
             tx.wit.vtxinwit[0].scriptWitness.stack = [CScript([OP_TRUE]), bytes([LEAF_VERSION_TAPSCRIPT]) + self._internal_key]
         tx_hex = tx.serialize().hex()
 
-        tx_info = from_node.testmempoolaccept([tx_hex])[0]
-        assert_equal(mempool_valid, tx_info['allowed'])
         if mempool_valid:
+            tx_info = from_node.testmempoolaccept([tx_hex])[0]
+            assert_equal(tx_info['allowed'], True)
             assert_equal(tx_info['vsize'], vsize)
             assert_equal(tx_info['fees']['base'], utxo_to_spend['value'] - Decimal(send_value) / COIN)
-        return {'txid': tx_info['txid'], 'wtxid': tx_info['wtxid'], 'hex': tx_hex, 'tx': tx}
+
+        return {'txid': tx.rehash(), 'wtxid': tx.getwtxid(), 'hex': tx_hex, 'tx': tx}
 
     def sendrawtransaction(self, *, from_node, tx_hex, **kwargs):
         txid = from_node.sendrawtransaction(hexstring=tx_hex, **kwargs)