Merge bitcoin#30410: rpc, rest: Improve block rpc error handling, check header before attempting to read block data.

6a1aa51 rpc: check block index before reading block / undo data (Martin Zumsande)
6cbf2e5 rpc: Improve gettxoutproof error when only header is available. (Martin Zumsande)
69fc867 test: add coverage to getblock and getblockstats (Martin Zumsande)
5290cbd rpc: Improve getblock / getblockstats error when only header is available. (Martin Zumsande)
e5b537b rest: improve error when only header of a block is available. (Martin Zumsande)

Pull request description:

  Fixes bitcoin#20978

  If a block was pruned, `getblock` already returns a specific error: "Block not available (pruned data)".
  But if we haven't received the full block yet (e.g. in a race with block downloading after a new block was received headers-first, or during IBD) we just return an unspecific "Block not found on disk" error and log
  `ERROR: ReadBlockFromDisk: OpenBlockFile failed for FlatFilePos(nFile=-1, nPos=0) `
  which suggest something went wrong even though this is a completely normal and expected situation.

  This PR improves the error message and stops calling `ReadRawBlockFromDisk()`, when we already know from the header that the block is not available on disk.
  Similarly, it prevents all other rpcs from calling blockstorage read functions unless we expect the data to be there, so that `LogError()` will only be thrown when there is an actual file system problem.

  I'm not  completely sure if the cause is important enough to change the wording of the rpc error, that some scripts may rely on.
  If reviewers prefer it, an alternative solution would be to keep returning the current "Block not found on disk" error, but return it immediately instead of calling `ReadRawBlockFromDisk`, which would at least prevent the log error and also be an improvement in my opinion.

ACKs for top commit:
  fjahr:
    re-ACK 6a1aa51
  achow101:
    ACK 6a1aa51
  andrewtoth:
    re-ACK 6a1aa51

Tree-SHA512: 491aef880e8298a05841c4bf8eb913ef84820d1ad5415fd17d9b441bff181959ebfdd432b5eb8347dc9c568433f9a2384ca9d84cd72c79d8a58323ca117538fe

Author: achow101

src/rest.cpp

@@ -309,8 +309,11 @@ static bool rest_block(const std::any& context,
         if (!pblockindex) {
             return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
         }
-        if (chainman.m_blockman.IsBlockPruned(*pblockindex)) {
-            return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not available (pruned data)");
+        if (!(pblockindex->nStatus & BLOCK_HAVE_DATA)) {
+            if (chainman.m_blockman.IsBlockPruned(*pblockindex)) {
+                return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not available (pruned data)");
+            }
+            return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not available (not fully downloaded)");
         }
         pos = pblockindex->GetBlockPos();
     }

src/rpc/blockchain.cpp

@@ -201,8 +201,10 @@ UniValue blockToJSON(BlockManager& blockman, const CBlock& block, const CBlockIn
         case TxVerbosity::SHOW_DETAILS_AND_PREVOUT:
             CBlockUndo blockUndo;
             const bool is_not_pruned{WITH_LOCK(::cs_main, return !blockman.IsBlockPruned(blockindex))};
-            const bool have_undo{is_not_pruned && blockman.UndoReadFromDisk(blockUndo, blockindex)};
-
+            bool have_undo{is_not_pruned && WITH_LOCK(::cs_main, return blockindex.nStatus & BLOCK_HAVE_UNDO)};
+            if (have_undo && !blockman.UndoReadFromDisk(blockUndo, blockindex)) {
+                throw JSONRPCError(RPC_INTERNAL_ERROR, "Undo data expected but can't be read. This could be due to disk corruption or a conflict with a pruning event.");
+            }
             for (size_t i = 0; i < block.vtx.size(); ++i) {
                 const CTransactionRef& tx = block.vtx.at(i);
                 // coinbase transaction (i.e. i == 0) doesn't have undo data
@@ -597,20 +599,32 @@ static RPCHelpMan getblockheader()
     };
 }
 
+void CheckBlockDataAvailability(BlockManager& blockman, const CBlockIndex& blockindex, bool check_for_undo)
+{
+    AssertLockHeld(cs_main);
+    uint32_t flag = check_for_undo ? BLOCK_HAVE_UNDO : BLOCK_HAVE_DATA;
+    if (!(blockindex.nStatus & flag)) {
+        if (blockman.IsBlockPruned(blockindex)) {
+            throw JSONRPCError(RPC_MISC_ERROR, strprintf("%s not available (pruned data)", check_for_undo ? "Undo data" : "Block"));
+        }
+        if (check_for_undo) {
+            throw JSONRPCError(RPC_MISC_ERROR, "Undo data not available");
+        }
+        throw JSONRPCError(RPC_MISC_ERROR, "Block not available (not fully downloaded)");
+    }
+}
+
 static CBlock GetBlockChecked(BlockManager& blockman, const CBlockIndex& blockindex)
 {
     CBlock block;
     {
         LOCK(cs_main);
-        if (blockman.IsBlockPruned(blockindex)) {
-            throw JSONRPCError(RPC_MISC_ERROR, "Block not available (pruned data)");
-        }
+        CheckBlockDataAvailability(blockman, blockindex, /*check_for_undo=*/false);
     }
 
     if (!blockman.ReadBlockFromDisk(block, blockindex)) {
-        // Block not found on disk. This could be because we have the block
-        // header in our index but not yet have the block or did not accept the
-        // block. Or if the block was pruned right after we released the lock above.
+        // Block not found on disk. This shouldn't normally happen unless the block was
+        // pruned right after we released the lock above.
         throw JSONRPCError(RPC_MISC_ERROR, "Block not found on disk");
     }
 
@@ -623,16 +637,13 @@ static std::vector<uint8_t> GetRawBlockChecked(BlockManager& blockman, const CBl
     FlatFilePos pos{};
     {
         LOCK(cs_main);
-        if (blockman.IsBlockPruned(blockindex)) {
-            throw JSONRPCError(RPC_MISC_ERROR, "Block not available (pruned data)");
-        }
+        CheckBlockDataAvailability(blockman, blockindex, /*check_for_undo=*/false);
         pos = blockindex.GetBlockPos();
     }
 
     if (!blockman.ReadRawBlockFromDisk(data, pos)) {
-        // Block not found on disk. This could be because we have the block
-        // header in our index but not yet have the block or did not accept the
-        // block. Or if the block was pruned right after we released the lock above.
+        // Block not found on disk. This shouldn't normally happen unless the block was
+        // pruned right after we released the lock above.
         throw JSONRPCError(RPC_MISC_ERROR, "Block not found on disk");
     }
 
@@ -648,9 +659,7 @@ static CBlockUndo GetUndoChecked(BlockManager& blockman, const CBlockIndex& bloc
 
     {
         LOCK(cs_main);
-        if (blockman.IsBlockPruned(blockindex)) {
-            throw JSONRPCError(RPC_MISC_ERROR, "Undo data not available (pruned data)");
-        }
+        CheckBlockDataAvailability(blockman, blockindex, /*check_for_undo=*/true);
     }
 
     if (!blockman.UndoReadFromDisk(blockUndo, blockindex)) {

src/rpc/blockchain.h

@@ -60,5 +60,6 @@ UniValue CreateUTXOSnapshot(
 
 //! Return height of highest block that has been pruned, or std::nullopt if no blocks have been pruned
 std::optional<int> GetPruneHeight(const node::BlockManager& blockman, const CChain& chain) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
+void CheckBlockDataAvailability(node::BlockManager& blockman, const CBlockIndex& blockindex, bool check_for_undo) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
 #endif // BITCOIN_RPC_BLOCKCHAIN_H

src/rpc/rawtransaction.cpp

@@ -405,11 +405,16 @@ static RPCHelpMan getrawtransaction()
     CBlockUndo blockUndo;
     CBlock block;
 
-    if (tx->IsCoinBase() || !blockindex || WITH_LOCK(::cs_main, return chainman.m_blockman.IsBlockPruned(*blockindex)) ||
-        !(chainman.m_blockman.UndoReadFromDisk(blockUndo, *blockindex) && chainman.m_blockman.ReadBlockFromDisk(block, *blockindex))) {
+    if (tx->IsCoinBase() || !blockindex || WITH_LOCK(::cs_main, return !(blockindex->nStatus & BLOCK_HAVE_MASK))) {
         TxToJSON(*tx, hash_block, result, chainman.ActiveChainstate());
         return result;
     }
+    if (!chainman.m_blockman.UndoReadFromDisk(blockUndo, *blockindex)) {
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Undo data expected but can't be read. This could be due to disk corruption or a conflict with a pruning event.");
+    }
+    if (!chainman.m_blockman.ReadBlockFromDisk(block, *blockindex)) {
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Block data expected but can't be read. This could be due to disk corruption or a conflict with a pruning event.");
+    }
 
     CTxUndo* undoTX {nullptr};
     auto it = std::find_if(block.vtx.begin(), block.vtx.end(), [tx](CTransactionRef t){ return *t == *tx; });

src/rpc/txoutproof.cpp

@@ -10,6 +10,7 @@
 #include <merkleblock.h>
 #include <node/blockstorage.h>
 #include <primitives/transaction.h>
+#include <rpc/blockchain.h>
 #include <rpc/server.h>
 #include <rpc/server_util.h>
 #include <rpc/util.h>
@@ -96,6 +97,10 @@ static RPCHelpMan gettxoutproof()
                 }
             }
 
+            {
+                LOCK(cs_main);
+                CheckBlockDataAvailability(chainman.m_blockman, *pblockindex, /*check_for_undo=*/false);
+            }
             CBlock block;
             if (!chainman.m_blockman.ReadBlockFromDisk(block, *pblockindex)) {
                 throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");

test/functional/feature_assumeutxo.py

@@ -313,7 +313,7 @@ def test_sync_from_assumeutxo_node(self, snapshot):
         self.connect_nodes(snapshot_node.index, miner.index)
         self.sync_blocks(nodes=(miner, snapshot_node))
         # Check the base snapshot block was stored and ensure node signals full-node service support
-        self.wait_until(lambda: not try_rpc(-1, "Block not found", snapshot_node.getblock, snapshot_block_hash))
+        self.wait_until(lambda: not try_rpc(-1, "Block not available (not fully downloaded)", snapshot_node.getblock, snapshot_block_hash))
         self.wait_until(lambda: 'NETWORK' in snapshot_node.getnetworkinfo()['localservicesnames'])
 
         # Now that the snapshot_node is synced, verify the ibd_node can sync from it
@@ -485,7 +485,7 @@ def check_dump_output(output):
         # find coinbase output at snapshot height on node0 and scan for it on node1,
         # where the block is not available, but the snapshot was loaded successfully
         coinbase_tx = n0.getblock(snapshot_hash, verbosity=2)['tx'][0]
-        assert_raises_rpc_error(-1, "Block not found on disk", n1.getblock, snapshot_hash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", n1.getblock, snapshot_hash)
         coinbase_output_descriptor = coinbase_tx['vout'][0]['scriptPubKey']['desc']
         scan_result = n1.scantxoutset('start', [coinbase_output_descriptor])
         assert_equal(scan_result['success'], True)
@@ -557,7 +557,7 @@ def check_tx_counts(final: bool) -> None:
         self.log.info("Submit a spending transaction for a snapshot chainstate coin to the mempool")
         # spend the coinbase output of the first block that is not available on node1
         spend_coin_blockhash = n1.getblockhash(START_HEIGHT + 1)
-        assert_raises_rpc_error(-1, "Block not found on disk", n1.getblock, spend_coin_blockhash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", n1.getblock, spend_coin_blockhash)
         prev_tx = n0.getblock(spend_coin_blockhash, 3)['tx'][0]
         prevout = {"txid": prev_tx['txid'], "vout": 0, "scriptPubKey": prev_tx['vout'][0]['scriptPubKey']['hex']}
         privkey = n0.get_deterministic_priv_key().key

test/functional/p2p_node_network_limited.py

@@ -102,10 +102,10 @@ def test_avoid_requesting_historical_blocks(self):
         tip_height = pruned_node.getblockcount()
         limit_buffer = 2
         # Prevent races by waiting for the tip to arrive first
-        self.wait_until(lambda: not try_rpc(-1, "Block not found", full_node.getblock, pruned_node.getbestblockhash()))
+        self.wait_until(lambda: not try_rpc(-1, "Block not available (not fully downloaded)", full_node.getblock, pruned_node.getbestblockhash()))
         for height in range(start_height_full_node + 1, tip_height + 1):
             if height <= tip_height - (NODE_NETWORK_LIMITED_MIN_BLOCKS - limit_buffer):
-                assert_raises_rpc_error(-1, "Block not found on disk", full_node.getblock, pruned_node.getblockhash(height))
+                assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", full_node.getblock, pruned_node.getblockhash(height))
             else:
                 full_node.getblock(pruned_node.getblockhash(height))  # just assert it does not throw an exception
 

test/functional/p2p_unrequested_blocks.py

@@ -119,7 +119,7 @@ def run_test(self):
                 assert_equal(x['status'], "headers-only")
                 tip_entry_found = True
         assert tip_entry_found
-        assert_raises_rpc_error(-1, "Block not found on disk", self.nodes[0].getblock, block_h1f.hash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", self.nodes[0].getblock, block_h1f.hash)
 
         # 4. Send another two block that build on the fork.
         block_h2f = create_block(block_h1f.sha256, create_coinbase(2), block_time)
@@ -191,7 +191,7 @@ def run_test(self):
         # Blocks 1-287 should be accepted, block 288 should be ignored because it's too far ahead
         for x in all_blocks[:-1]:
             self.nodes[0].getblock(x.hash)
-        assert_raises_rpc_error(-1, "Block not found on disk", self.nodes[0].getblock, all_blocks[-1].hash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", self.nodes[0].getblock, all_blocks[-1].hash)
 
         # 5. Test handling of unrequested block on the node that didn't process
         # Should still not be processed (even though it has a child that has more
@@ -230,7 +230,7 @@ def run_test(self):
         assert_equal(self.nodes[0].getblockcount(), 290)
         self.nodes[0].getblock(all_blocks[286].hash)
         assert_equal(self.nodes[0].getbestblockhash(), all_blocks[286].hash)
-        assert_raises_rpc_error(-1, "Block not found on disk", self.nodes[0].getblock, all_blocks[287].hash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", self.nodes[0].getblock, all_blocks[287].hash)
         self.log.info("Successfully reorged to longer chain")
 
         # 8. Create a chain which is invalid at a height longer than the
@@ -260,7 +260,7 @@ def run_test(self):
                 assert_equal(x['status'], "headers-only")
                 tip_entry_found = True
         assert tip_entry_found
-        assert_raises_rpc_error(-1, "Block not found on disk", self.nodes[0].getblock, block_292.hash)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", self.nodes[0].getblock, block_292.hash)
 
         test_node.send_message(msg_block(block_289f))
         test_node.send_and_ping(msg_block(block_290f))

test/functional/rpc_blockchain.py

@@ -32,14 +32,16 @@
     TIME_GENESIS_BLOCK,
     create_block,
     create_coinbase,
+    create_tx_with_script,
 )
 from test_framework.messages import (
     CBlockHeader,
+    COIN,
     from_hex,
     msg_block,
 )
 from test_framework.p2p import P2PInterface
-from test_framework.script import hash256
+from test_framework.script import hash256, OP_TRUE
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import (
     assert_equal,
@@ -556,12 +558,12 @@ def assert_hexblock_hashes(verbosity):
             block = node.getblock(blockhash, verbosity)
             assert_equal(blockhash, hash256(bytes.fromhex(block[:160]))[::-1].hex())
 
-        def assert_fee_not_in_block(verbosity):
-            block = node.getblock(blockhash, verbosity)
+        def assert_fee_not_in_block(hash, verbosity):
+            block = node.getblock(hash, verbosity)
             assert 'fee' not in block['tx'][1]
 
-        def assert_fee_in_block(verbosity):
-            block = node.getblock(blockhash, verbosity)
+        def assert_fee_in_block(hash, verbosity):
+            block = node.getblock(hash, verbosity)
             tx = block['tx'][1]
             assert 'fee' in tx
             assert_equal(tx['fee'], tx['vsize'] * fee_per_byte)
@@ -580,8 +582,8 @@ def assert_vin_contains_prevout(verbosity):
                 total_vout += vout["value"]
             assert_equal(total_vin, total_vout + tx["fee"])
 
-        def assert_vin_does_not_contain_prevout(verbosity):
-            block = node.getblock(blockhash, verbosity)
+        def assert_vin_does_not_contain_prevout(hash, verbosity):
+            block = node.getblock(hash, verbosity)
             tx = block["tx"][1]
             if isinstance(tx, str):
                 # In verbosity level 1, only the transaction hashes are written
@@ -595,24 +597,24 @@ def assert_vin_does_not_contain_prevout(verbosity):
         assert_hexblock_hashes(False)
 
         self.log.info("Test that getblock with verbosity 1 doesn't include fee")
-        assert_fee_not_in_block(1)
-        assert_fee_not_in_block(True)
+        assert_fee_not_in_block(blockhash, 1)
+        assert_fee_not_in_block(blockhash, True)
 
         self.log.info('Test that getblock with verbosity 2 and 3 includes expected fee')
-        assert_fee_in_block(2)
-        assert_fee_in_block(3)
+        assert_fee_in_block(blockhash, 2)
+        assert_fee_in_block(blockhash, 3)
 
         self.log.info("Test that getblock with verbosity 1 and 2 does not include prevout")
-        assert_vin_does_not_contain_prevout(1)
-        assert_vin_does_not_contain_prevout(2)
+        assert_vin_does_not_contain_prevout(blockhash, 1)
+        assert_vin_does_not_contain_prevout(blockhash, 2)
 
         self.log.info("Test that getblock with verbosity 3 includes prevout")
         assert_vin_contains_prevout(3)
 
         self.log.info("Test getblock with invalid verbosity type returns proper error message")
         assert_raises_rpc_error(-3, "JSON value of type string is not of expected type number", node.getblock, blockhash, "2")
 
-        self.log.info("Test that getblock with verbosity 2 and 3 still works with pruned Undo data")
+        self.log.info("Test that getblock doesn't work with deleted Undo data")
 
         def move_block_file(old, new):
             old_path = self.nodes[0].blocks_path / old
@@ -622,17 +624,40 @@ def move_block_file(old, new):
         # Move instead of deleting so we can restore chain state afterwards
         move_block_file('rev00000.dat', 'rev_wrong')
 
-        assert_fee_not_in_block(2)
-        assert_fee_not_in_block(3)
-        assert_vin_does_not_contain_prevout(2)
-        assert_vin_does_not_contain_prevout(3)
+        assert_raises_rpc_error(-32603, "Undo data expected but can't be read. This could be due to disk corruption or a conflict with a pruning event.", lambda: node.getblock(blockhash, 2))
+        assert_raises_rpc_error(-32603, "Undo data expected but can't be read. This could be due to disk corruption or a conflict with a pruning event.", lambda: node.getblock(blockhash, 3))
 
         # Restore chain state
         move_block_file('rev_wrong', 'rev00000.dat')
 
         assert 'previousblockhash' not in node.getblock(node.getblockhash(0))
         assert 'nextblockhash' not in node.getblock(node.getbestblockhash())
 
+        self.log.info("Test getblock when only header is known")
+        current_height = node.getblock(node.getbestblockhash())['height']
+        block_time = node.getblock(node.getbestblockhash())['time'] + 1
+        block = create_block(int(blockhash, 16), create_coinbase(current_height + 1, nValue=100), block_time)
+        block.solve()
+        node.submitheader(block.serialize().hex())
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", lambda: node.getblock(block.hash))
+
+        self.log.info("Test getblock when block data is available but undo data isn't")
+        # Submits a block building on the header-only block, so it can't be connected and has no undo data
+        tx = create_tx_with_script(block.vtx[0], 0, script_sig=bytes([OP_TRUE]), amount=50 * COIN)
+        block_noundo = create_block(block.sha256, create_coinbase(current_height + 2, nValue=100), block_time + 1, txlist=[tx])
+        block_noundo.solve()
+        node.submitblock(block_noundo.serialize().hex())
+
+        assert_fee_not_in_block(block_noundo.hash, 2)
+        assert_fee_not_in_block(block_noundo.hash, 3)
+        assert_vin_does_not_contain_prevout(block_noundo.hash, 2)
+        assert_vin_does_not_contain_prevout(block_noundo.hash, 3)
+
+        self.log.info("Test getblock when block is missing")
+        move_block_file('blk00000.dat', 'blk00000.dat.bak')
+        assert_raises_rpc_error(-1, "Block not found on disk", node.getblock, blockhash)
+        move_block_file('blk00000.dat.bak', 'blk00000.dat')
+
 
 if __name__ == '__main__':
     BlockchainTest(__file__).main()

test/functional/rpc_getblockfrompeer.py

@@ -58,7 +58,7 @@ def run_test(self):
         self.log.info("Node 0 should only have the header for node 1's block 3")
         x = next(filter(lambda x: x['hash'] == short_tip, self.nodes[0].getchaintips()))
         assert_equal(x['status'], "headers-only")
-        assert_raises_rpc_error(-1, "Block not found on disk", self.nodes[0].getblock, short_tip)
+        assert_raises_rpc_error(-1, "Block not available (not fully downloaded)", self.nodes[0].getblock, short_tip)
 
         self.log.info("Fetch block from node 1")
         peers = self.nodes[0].getpeerinfo()