test: Check for valid hashBlockCommitments construction post-NU5

qa/pull-tester/rpc-tests.py

@@ -116,6 +116,7 @@ BASE_SCRIPTS= [
     'framework.py',
     'sapling_rewind_check.py',
     'feature_zip221.py',
+    'feature_zip244_blockcommitments.py',
     'upgrade_golden.py',
     'post_heartwood_rollback.py',
     'feature_logging.py',

qa/rpc-tests/feature_zip244_blockcommitments.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+# Copyright (c) 2020 The Zcash developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://www.opensource.org/licenses/mit-license.php .
+
+
+from test_framework.blocktools import derive_block_commitments_hash
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    bytes_to_hex_str,
+    hex_str_to_bytes,
+    start_nodes,
+)
+
+TERMINATOR = b'\x00' * 32
+
+# Verify block header field 'hashLightClientRoot' is set correctly for NU5 blocks.
+class AuthDataRootTest(BitcoinTestFramework):
+
+    def __init__(self):
+        super().__init__()
+        self.num_nodes = 4
+
+    def setup_nodes(self):
+        return start_nodes(self.num_nodes, self.options.tmpdir, extra_args=[[
+            '-nuparams=5ba81b19:1', # Overwinter
+            '-nuparams=76b809bb:1', # Sapling
+            '-nuparams=2bb40e60:201', # Blossom
+            '-nuparams=f5b9230b:201', # Heartwood
+            '-nuparams=e9ff75a6:201', # Canopy
+            '-nuparams=f919a198:205', # NU5
+            '-nurejectoldversions=false',
+        ]] * self.num_nodes)
+
+    def run_test(self):
+        # Generate a block so we are on Canopy rules.
+        self.nodes[0].generate(2)
+        self.sync_all()
+
+        # Before NU5 activation, the hashBlockCommitments field of the block
+        # header contains the root of the ZIP 221 history tree.
+        block_before = self.nodes[0].getblock('202')
+        assert_equal(block_before['blockcommitments'], block_before['chainhistoryroot'])
+
+        # Generate blocks until we are on NU5 rules.
+        self.nodes[0].generate(3)
+        self.sync_all()
+
+        # From NU5 activation, the hashBlockCommitments field of the block
+        # header contains a hash of various block commitments (per ZIP 244).
+        block_after = self.nodes[0].getblock('205')
+        block_commitments = bytes_to_hex_str(derive_block_commitments_hash(
+            hex_str_to_bytes(block_after['chainhistoryroot'])[::-1],
+            hex_str_to_bytes(block_after['authdataroot'])[::-1],
+        )[::-1])
+        assert_equal(block_after['blockcommitments'], block_commitments)
+
+
+if __name__ == '__main__':
+    AuthDataRootTest().main()

qa/rpc-tests/test_framework/blocktools.py

@@ -4,6 +4,8 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
+from pyblake2 import blake2b
+
 from .mininode import CBlock, CTransaction, CTxIn, CTxOut, COutPoint
 from .script import CScript, OP_0, OP_EQUAL, OP_HASH160, OP_TRUE, OP_CHECKSIG
 
@@ -29,6 +31,15 @@ def create_block(hashprev, coinbase, nTime=None, nBits=None, hashFinalSaplingRoo
     block.calc_sha256()
     return block
 
+def derive_block_commitments_hash(chain_history_root, auth_data_root):
+    digest = blake2b(
+        digest_size=32,
+        person=b'ZcashBlockCommit')
+    digest.update(chain_history_root)
+    digest.update(auth_data_root)
+    digest.update(b'\x00' * 32)
+    return digest.digest()
+
 def serialize_script_num(value):
     r = bytearray(0)
     if value == 0:

src/rpc/blockchain.cpp

@@ -233,6 +233,8 @@ UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool tx
     result.pushKV("height", blockindex->nHeight);
     result.pushKV("version", block.nVersion);
     result.pushKV("merkleroot", block.hashMerkleRoot.GetHex());
+    result.pushKV("blockcommitments", blockindex->hashBlockCommitments.GetHex());
+    result.pushKV("authdataroot", blockindex->hashAuthDataRoot.GetHex());
     result.pushKV("finalsaplingroot", blockindex->hashFinalSaplingRoot.GetHex());
     result.pushKV("chainhistoryroot", blockindex->hashChainHistoryRoot.GetHex());
     UniValue txs(UniValue::VARR);