test: Use result of getblocktemplate to submitblock

This will ensure that miners can use the values returned by
getblocktemplate (in particular, the block commitment hash)
to submit a valid block using the submitblock RPC.

qa/rpc-tests/getblocktemplate.py

@@ -3,6 +3,8 @@
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
+from io import BytesIO
+import codecs
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
@@ -10,13 +12,24 @@ from test_framework.util import (
     CANOPY_BRANCH_ID,
     HEARTWOOD_BRANCH_ID,
     NU5_BRANCH_ID,
+    get_coinbase_address,
+    hex_str_to_bytes,
     nuparams,
     start_nodes,
+    wait_and_assert_operationid_status,
 )
+from test_framework.mininode import (
+    CTransaction,
+)
+from test_framework.blocktools import(
+    create_block
+)
+from decimal import Decimal
 
 class GetBlockTemplateTest(BitcoinTestFramework):
     '''
-    Test getblocktemplate.
+    Test getblocktemplate, ensure that a block created from its result
+    can be submitted and accepted.
     '''
 
     def __init__(self):
@@ -25,7 +38,8 @@ class GetBlockTemplateTest(BitcoinTestFramework):
         self.setup_clean_chain = True
 
     def setup_network(self, split=False):
-        args = [nuparams(BLOSSOM_BRANCH_ID, 1),
+        args = [
+            nuparams(BLOSSOM_BRANCH_ID, 1),
             nuparams(HEARTWOOD_BRANCH_ID, 1),
             nuparams(CANOPY_BRANCH_ID, 1),
             nuparams(NU5_BRANCH_ID, 1),
@@ -36,40 +50,56 @@ class GetBlockTemplateTest(BitcoinTestFramework):
 
     def run_test(self):
         node = self.nodes[0]
-        node.generate(1) # Mine a block to leave initial block download
+        print("Generating blocks")
+        node.generate(110)
 
-        # Test 1: Default to coinbasetxn
-        tmpl = node.getblocktemplate()
-        assert('coinbasetxn' in tmpl)
-        assert('coinbasevalue' not in tmpl)
+        print("Add transactions to the mempool so they will be in the template")
+        # This part of the test should be improved, submit some V4 transactions
+        # and varying combinations of shielded and transparent
+        for _ in range(5):
+            # submit a tx with a shielded output
+            taddr0 = get_coinbase_address(node)
+            zaddr = node.z_getnewaddress('sapling')
+            recipients = [{"address": zaddr, "amount": Decimal('0.1')}]
+            myopid = node.z_sendmany(taddr0, recipients, 1, 0)
+            wait_and_assert_operationid_status(node, myopid)
 
-        # Test 2: Get coinbasetxn if requested
-        tmpl = node.getblocktemplate({'capabilities': ['coinbasetxn']})
-        assert('coinbasetxn' in tmpl)
-        assert('coinbasevalue' not in tmpl)
+            # submit a tx with a transparent output
+            outputs = {node.getnewaddress():0.2}
+            node.sendmany('', outputs)
 
-        # Test 3: coinbasevalue not supported if requested
-        tmpl = node.getblocktemplate({'capabilities': ['coinbasevalue']})
-        assert('coinbasetxn' in tmpl)
-        assert('coinbasevalue' not in tmpl)
+        print("Getting block template")
+        gbt = node.getblocktemplate()
 
-        # Test 4: coinbasevalue not supported if both requested
-        tmpl = node.getblocktemplate({'capabilities': ['coinbasetxn', 'coinbasevalue']})
-        assert('coinbasetxn' in tmpl)
-        assert('coinbasevalue' not in tmpl)
+        prevhash = int(gbt['previousblockhash'], 16)
+        blockcommitmentshash = int(gbt['defaultroots']['blockcommitmentshash'], 16)
+        nTime = gbt['mintime']
+        nBits = int(gbt['bits'], 16)
 
-        # Test 5: General checks
-        tmpl = node.getblocktemplate()
-        assert_equal(16, len(tmpl['noncerange']))
-        # should be proposing height 2, since current tip is height 1
-        assert_equal(2, tmpl['height'])
+        f = BytesIO(hex_str_to_bytes(gbt['coinbasetxn']['data']))
+        coinbase = CTransaction()
+        coinbase.deserialize(f)
 
-        # Test 6: coinbasetxn checks
-        assert(tmpl['coinbasetxn']['required'])
+        print("Creating_block from template (simulating a miner)")
+        block = create_block(prevhash, coinbase, nTime, nBits, blockcommitmentshash)
+
+        # copy the non-coinbase transactions from the block template to the block
+        for gbt_tx in gbt['transactions']:
+            f = BytesIO(hex_str_to_bytes(gbt_tx['data']))
+            tx = CTransaction()
+            tx.deserialize(f)
+            block.vtx.append(tx)
+        block.hashMerkleRoot = int(gbt['defaultroots']['merkleroot'], 16)
+        assert_equal(block.hashMerkleRoot, block.calc_merkle_root(), "merkleroot")
+        assert_equal(len(block.vtx), len(gbt['transactions']) + 1, "number of transactions")
+        assert_equal(block.hashPrevBlock, int(gbt['previousblockhash'], 16), "prevhash")
+        block.solve()
+        block = block.serialize()
+        block = codecs.encode(block, 'hex_codec')
+
+        print("Submitting block")
+        node.submitblock(block)
 
-        # Test 7: blockcommitmentshash checks
-        assert('blockcommitmentshash' in tmpl)
-        assert('00' * 32 != tmpl['finalsaplingroothash'])
 
 if __name__ == '__main__':
     GetBlockTemplateTest().main()

src/rpc/mining.cpp

@@ -449,9 +449,15 @@ UniValue getblocktemplate(const UniValue& params, bool fHelp)
             "{\n"
             "  \"version\" : n,                     (numeric) The block version\n"
             "  \"previousblockhash\" : \"xxxx\",      (string) The hash of current highest block\n"
-            "  \"blockcommitmentshash\" : \"xxxx\",   (string) The hash of the block commitments field in the block header\n"
+            "  \"blockcommitmentshash\" : \"xxxx\",   (string) (DEPRECATED) The hash of the block commitments field in the block header\n"
             "  \"lightclientroothash\" : \"xxxx\",    (string) (DEPRECATED) The hash of the light client root field in the block header\n"
             "  \"finalsaplingroothash\" : \"xxxx\",   (string) (DEPRECATED) The hash of the light client root field in the block header\n"
+            "  \"defaultroots\" : {                 (json object) root hashes that need to be recomputed if the transaction set is modified\n"
+            "     \"merkleroot\" : \"xxxx\"           (string) The hash of the transactions in the block header\n"
+            "     \"authdataroot\" : \"xxxx\"         (string) The hash of the authorizing data merkel tree\n"
+            "     \"chainhistoryroot\" : \"xxxx\"     (string) The hash of the chain history\n"
+            "     \"blockcommitmentshash\" : \"xxxx\" (string) The hash of the block commitments field in the block header\n"
+            "  }\n"
             "  \"transactions\" : [                 (array) contents of non-coinbase transactions that should be included in the next block\n"
             "      {\n"
             "         \"data\" : \"xxxx\",            (string) transaction data encoded in hexadecimal (byte-for-byte)\n"