Merge #17693: rpc: Add generateblock to mine a custom set of transactions

7524b6479cb20471d827aec5500925c86c62ce1c Add tests for generateblock (Andrew Toth)
dcc8332543f8fb6d1bb47cb270fcbb6a814a7d6e Add generateblock rpc (Andrew Toth)

Pull request description:

  The existing block generation rpcs for regtest, `generatetoaddress` and `generatetodescriptor`, mine everything in the mempool up to the block weight limit. This makes it difficult to test a system for several scenarios where a different set of transactions are mined. For example:
  - Testing the common scenario where a transaction is replaced in the mempool but the replaced transaction is mined instead.
  - Testing for a double-spent transaction where a transaction that conflicts with the mempool is mined.
  - Testing for non-standard transactions that are mined.
  - Testing the scenario where several blocks are mined without a specific transaction in the mempool being included in a block.

  This PR introduces a new rpc, `generateblock`, that takes an array of raw transactions and txids and mines only those and the coinbase. Any txids must be in the mempool, but the raw txs can be anything conforming to consensus rules. The coinbase can be specified as either an address or descriptor.

  This reopens #17653 since it was closed by mistake.

  Thanks to instagibbs for code suggestions that I used here.

ACKs for top commit:
  MarcoFalke:
    re-ACK 7524b6479cb20471d827aec5500925c86c62ce1c 📁

Tree-SHA512: 857106007465b5b9b8a84b6d07c17cbf8378a33a72d32ff79abea1d5ab4babb4d53a11ddbb14595aa1fac9dfa1391e3a11403d742f69951beea2f683e8a01cd4

2 files changed, 106 insertions, 0 deletions

diff --git a/test/functional/rpc_generateblock.py b/test/functional/rpc_generateblock.py
new file mode 100755
index 0000000000..f23d9ec556
--- /dev/null
+++ b/test/functional/rpc_generateblock.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+'''Test generateblock rpc.
+'''
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    assert_raises_rpc_error,
+)
+
+class GenerateBlockTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def skip_test_if_missing_module(self):
+        self.skip_if_no_wallet()
+
+    def run_test(self):
+        node = self.nodes[0]
+
+        self.log.info('Generate an empty block to address')
+        address = node.getnewaddress()
+        hash = node.generateblock(address, [])['hash']
+        block = node.getblock(hash, 2)
+        assert_equal(len(block['tx']), 1)
+        assert_equal(block['tx'][0]['vout'][0]['scriptPubKey']['addresses'][0], address)
+
+        self.log.info('Generate an empty block to a descriptor')
+        hash = node.generateblock('addr(' + address + ')', [])['hash']
+        block = node.getblock(hash, 2)
+        assert_equal(len(block['tx']), 1)
+        assert_equal(block['tx'][0]['vout'][0]['scriptPubKey']['addresses'][0], address)
+
+        self.log.info('Generate an empty block to a combo descriptor with compressed pubkey')
+        combo_key = '0279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798'
+        combo_address = 'bcrt1qw508d6qejxtdg4y5r3zarvary0c5xw7kygt080'
+        hash = node.generateblock('combo(' + combo_key + ')', [])['hash']
+        block = node.getblock(hash, 2)
+        assert_equal(len(block['tx']), 1)
+        assert_equal(block['tx'][0]['vout'][0]['scriptPubKey']['addresses'][0], combo_address)
+
+        self.log.info('Generate an empty block to a combo descriptor with uncompressed pubkey')
+        combo_key = '0408ef68c46d20596cc3f6ddf7c8794f71913add807f1dc55949fa805d764d191c0b7ce6894c126fce0babc6663042f3dde9b0cf76467ea315514e5a6731149c67'
+        combo_address = 'mkc9STceoCcjoXEXe6cm66iJbmjM6zR9B2'
+        hash = node.generateblock('combo(' + combo_key + ')', [])['hash']
+        block = node.getblock(hash, 2)
+        assert_equal(len(block['tx']), 1)
+        assert_equal(block['tx'][0]['vout'][0]['scriptPubKey']['addresses'][0], combo_address)
+
+        # Generate 110 blocks to spend
+        node.generatetoaddress(110, address)
+
+        # Generate some extra mempool transactions to verify they don't get mined
+        for i in range(10):
+            node.sendtoaddress(address, 0.001)
+
+        self.log.info('Generate block with txid')
+        txid = node.sendtoaddress(address, 1)
+        hash = node.generateblock(address, [txid])['hash']
+        block = node.getblock(hash, 1)
+        assert_equal(len(block['tx']), 2)
+        assert_equal(block['tx'][1], txid)
+
+        self.log.info('Generate block with raw tx')
+        utxos = node.listunspent(addresses=[address])
+        raw = node.createrawtransaction([{'txid':utxos[0]['txid'], 'vout':utxos[0]['vout']}],[{address:1}])
+        signed_raw = node.signrawtransactionwithwallet(raw)['hex']
+        hash = node.generateblock(address, [signed_raw])['hash']
+        block = node.getblock(hash, 1)
+        assert_equal(len(block['tx']), 2)
+        txid = block['tx'][1]
+        assert_equal(node.gettransaction(txid)['hex'], signed_raw)
+
+        self.log.info('Fail to generate block with out of order txs')
+        raw1 = node.createrawtransaction([{'txid':txid, 'vout':0}],[{address:0.9999}])
+        signed_raw1 = node.signrawtransactionwithwallet(raw1)['hex']
+        txid1 = node.sendrawtransaction(signed_raw1)
+        raw2 = node.createrawtransaction([{'txid':txid1, 'vout':0}],[{address:0.999}])
+        signed_raw2 = node.signrawtransactionwithwallet(raw2)['hex']
+        assert_raises_rpc_error(-25, 'TestBlockValidity failed: bad-txns-inputs-missingorspent', node.generateblock, address, [signed_raw2, txid1])
+
+        self.log.info('Fail to generate block with txid not in mempool')
+        missing_txid = '0000000000000000000000000000000000000000000000000000000000000000'
+        assert_raises_rpc_error(-5, 'Transaction ' + missing_txid + ' not in mempool.', node.generateblock, address, [missing_txid])
+
+        self.log.info('Fail to generate block with invalid raw tx')
+        invalid_raw_tx = '0000'
+        assert_raises_rpc_error(-22, 'Transaction decode failed for ' + invalid_raw_tx, node.generateblock, address, [invalid_raw_tx])
+
+        self.log.info('Fail to generate block with invalid address/descriptor')
+        assert_raises_rpc_error(-5, 'Invalid address or descriptor', node.generateblock, '1234', [])
+
+        self.log.info('Fail to generate block with a ranged descriptor')
+        ranged_descriptor = 'pkh(tpubD6NzVbkrYhZ4XgiXtGrdW5XDAPFCL9h7we1vwNCpn8tGbBcgfVYjXyhWo4E1xkh56hjod1RhGjxbaTLV3X4FyWuejifB9jusQ46QzG87VKp/0/*)'
+        assert_raises_rpc_error(-8, 'Ranged descriptor not accepted. Maybe pass through deriveaddresses first?', node.generateblock, ranged_descriptor, [])
+
+        self.log.info('Fail to generate block with a descriptor missing a private key')
+        child_descriptor = 'pkh(tpubD6NzVbkrYhZ4XgiXtGrdW5XDAPFCL9h7we1vwNCpn8tGbBcgfVYjXyhWo4E1xkh56hjod1RhGjxbaTLV3X4FyWuejifB9jusQ46QzG87VKp/0\'/0)'
+        assert_raises_rpc_error(-5, 'Cannot derive script without private keys', node.generateblock, child_descriptor, [])
+
+if __name__ == '__main__':
+    GenerateBlockTest().main()
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
index faa2dee4ed..ee71de3310 100755
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -173,6 +173,7 @@ BASE_SCRIPTS = [
     'wallet_importprunedfunds.py',
     'p2p_leak_tx.py',
     'rpc_signmessage.py',
+    'rpc_generateblock.py',
     'wallet_balance.py',
     'feature_nulldummy.py',
     'mempool_accept.py',