Merge f5cded8829 into 85f96b01b7

9d2d9f7ce2 rpc: Include assumeutxo as a failure reason of rescanblockchain (Fabian Jahr)
595edee169 test, assumeutxo: import descriptors during background sync (Alfonso Roman Zubeldia)
d73ae603d4 rpc: Improve importdescriptor RPC error messages (Fabian Jahr)
27f99b6d63 validation: Don't assume m_chain_tx_count in GuessVerificationProgress (Fabian Jahr)
42d5d53363 interfaces: Add helper function for wallet on pruning (Fabian Jahr)

Pull request description:

  A test that is added as part of #30455 uncovered this issue: The `GuessVerificationProgress` function is used during during descriptor import and relies on `m_chain_tx_count`. In #29370 an [`Assume` was added](0fd915ee6b) expecting the `m_chaint_tx_count` to be set. However, as the test uncovered, `GuessVerificationProgress` is called with background sync blocks that have `m_chaint_tx_count = 0` when they have not been downloaded and processed yet.

  The simple fix is to remove the `Assume`. Users should not be thrown off by the `Internal bug detected` error. The behavior of `importdescriptor` is kept consistent with the behavior for blocks missing due to pruning.

  The test by alfonsoromanz is cherry-picked here to show that the [CI errors](https://cirrus-ci.com/task/5110045812195328?logs=ci#L2535) should be fixed by this change.

  This PR also improves error messages returned by the `importdescriptors` and `rescanblockchain` RPCs. The error message now changes depending on the situation of the node, i.e. if pruning is happening or an assumutxo backgroundsync is active.

ACKs for top commit:
  achow101:
    ACK 9d2d9f7ce2
  mzumsande:
    Code Review ACK 9d2d9f7ce2
  furszy:
    Code review ACK 9d2d9f7ce2

Tree-SHA512: b841a9b371e5eb8eb3bfebca35645ff2fdded7a3e5e06308d46a33a51ca42cc4c258028c9958fbbb6cda9bb990e07ab8d8504dd9ec6705ef78afe0435912b365

doc/release-notes-31600.md

@@ -0,0 +1,11 @@
+Updated RPCs
+---
+- the `getblocktemplate` RPC `curtime` (BIP22) and `mintime` (BIP23) fields now
+  account for the timewarp fix proposed in BIP94 on all networks. This ensures
+  that, in the event a timewarp fix softfork activates on mainnet, un-upgraded
+  miners will not accidentally violate the timewarp rule. (#31376, #31600)
+
+As a reminder, it's important that any software which uses the `getblocktemplate`
+RPC takes these values into account (either `curtime` or `mintime` is fine).
+Relying only on a clock can lead to invalid blocks under some circumstances,
+especially once a timewarp fix is deployed.

src/bitcoin-chainstate.cpp

@@ -106,6 +106,7 @@ int main(int argc, char* argv[])
     };
     auto notifications = std::make_unique<KernelNotifications>();
 
+    kernel::CacheSizes cache_sizes{DEFAULT_KERNEL_CACHE};
 
     // SETUP: Chainstate
     auto chainparams = CChainParams::Main();
@@ -119,11 +120,14 @@ int main(int argc, char* argv[])
         .chainparams = chainman_opts.chainparams,
         .blocks_dir = abs_datadir / "blocks",
         .notifications = chainman_opts.notifications,
+        .block_tree_db_params = DBParams{
+            .path = abs_datadir / "blocks" / "index",
+            .cache_bytes = cache_sizes.block_tree_db,
+        },
     };
     util::SignalInterrupt interrupt;
     ChainstateManager chainman{interrupt, chainman_opts, blockman_opts};
 
-    kernel::CacheSizes cache_sizes{DEFAULT_KERNEL_CACHE};
     node::ChainstateLoadOptions options;
     auto [status, error] = node::LoadChainstate(chainman, cache_sizes, options);
     if (status != node::ChainstateLoadStatus::SUCCESS) {

src/init.cpp

@@ -1057,6 +1057,10 @@ bool AppInitParameterInteraction(const ArgsManager& args)
             .chainparams = chainman_opts_dummy.chainparams,
             .blocks_dir = args.GetBlocksDirPath(),
             .notifications = chainman_opts_dummy.notifications,
+            .block_tree_db_params = DBParams{
+                .path = args.GetDataDirNet() / "blocks" / "index",
+                .cache_bytes = 0,
+            },
         };
         auto blockman_result{ApplyArgsManOptions(args, blockman_opts_dummy)};
         if (!blockman_result) {
@@ -1203,18 +1207,33 @@ static ChainstateLoadResult InitAndLoadChainstate(
         .signals = node.validation_signals.get(),
     };
     Assert(ApplyArgsManOptions(args, chainman_opts)); // no error can happen, already checked in AppInitParameterInteraction
+
     BlockManager::Options blockman_opts{
         .chainparams = chainman_opts.chainparams,
         .blocks_dir = args.GetBlocksDirPath(),
         .notifications = chainman_opts.notifications,
+        .block_tree_db_params = DBParams{
+            .path = args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = cache_sizes.block_tree_db,
+            .wipe_data = do_reindex,
+        },
     };
     Assert(ApplyArgsManOptions(args, blockman_opts)); // no error can happen, already checked in AppInitParameterInteraction
+
+    // Creating the chainstate manager internally creates a BlockManager, opens
+    // the blocks tree db, and wipes existing block files in case of a reindex.
+    // The coinsdb is opened at a later point on LoadChainstate.
     try {
         node.chainman = std::make_unique<ChainstateManager>(*Assert(node.shutdown_signal), chainman_opts, blockman_opts);
+    } catch (dbwrapper_error& e) {
+        LogError("%s", e.what());
+        return {ChainstateLoadStatus::FAILURE, _("Error opening block database")};
     } catch (std::exception& e) {
         return {ChainstateLoadStatus::FAILURE_FATAL, Untranslated(strprintf("Failed to initialize ChainstateManager: %s", e.what()))};
     }
     ChainstateManager& chainman = *node.chainman;
+    if (chainman.m_interrupt) return {ChainstateLoadStatus::INTERRUPTED, {}};
+
     // This is defined and set here instead of inline in validation.h to avoid a hard
     // dependency between validation and index/base, since the latter is not in
     // libbitcoinkernel.
@@ -1237,7 +1256,6 @@ static ChainstateLoadResult InitAndLoadChainstate(
     };
     node::ChainstateLoadOptions options;
     options.mempool = Assert(node.mempool.get());
-    options.wipe_block_tree_db = do_reindex;
     options.wipe_chainstate_db = do_reindex || do_reindex_chainstate;
     options.prune = chainman.m_blockman.IsPruneMode();
     options.check_blocks = args.GetIntArg("-checkblocks", DEFAULT_CHECKBLOCKS);

src/interfaces/chain.h

@@ -289,6 +289,9 @@ public:
     //! Check if any block has been pruned.
     virtual bool havePruned() = 0;
 
+    //! Get the current prune height.
+    virtual std::optional<int> getPruneHeight() = 0;
+
     //! Check if the node is ready to broadcast transactions.
     virtual bool isReadyToBroadcast() = 0;
 

src/kernel/blockmanager_opts.h

@@ -5,6 +5,7 @@
 #ifndef BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
 #define BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
 
+#include <dbwrapper.h>
 #include <kernel/notifications_interface.h>
 #include <util/fs.h>
 
@@ -27,6 +28,7 @@ struct BlockManagerOpts {
     bool fast_prune{false};
     const fs::path blocks_dir;
     Notifications& notifications;
+    DBParams block_tree_db_params;
 };
 
 } // namespace kernel

src/kernel/chainstatemanager_opts.h

@@ -42,7 +42,6 @@ struct ChainstateManagerOpts {
     std::optional<uint256> assumed_valid_block{};
     //! If the tip is older than this, the node is considered to be in initial block download.
     std::chrono::seconds max_tip_age{DEFAULT_MAX_TIP_AGE};
-    DBOptions block_tree_db{};
     DBOptions coins_db{};
     CoinsViewOptions coins_view{};
     Notifications& notifications;

src/node/blockmanager_args.cpp

@@ -6,6 +6,7 @@
 
 #include <common/args.h>
 #include <node/blockstorage.h>
+#include <node/database_args.h>
 #include <tinyformat.h>
 #include <util/result.h>
 #include <util/translation.h>
@@ -34,6 +35,8 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& args, BlockManager::Op
 
     if (auto value{args.GetBoolArg("-fastprune")}) opts.fast_prune = *value;
 
+    ReadDatabaseArgs(args, opts.block_tree_db_params.options);
+
     return {};
 }
 } // namespace node

src/node/blockstorage.cpp

@@ -36,6 +36,7 @@
 #include <util/translation.h>
 #include <validation.h>
 
+#include <cstddef>
 #include <map>
 #include <ranges>
 #include <unordered_map>
@@ -1169,7 +1170,19 @@ BlockManager::BlockManager(const util::SignalInterrupt& interrupt, Options opts)
       m_opts{std::move(opts)},
       m_block_file_seq{FlatFileSeq{m_opts.blocks_dir, "blk", m_opts.fast_prune ? 0x4000 /* 16kB */ : BLOCKFILE_CHUNK_SIZE}},
       m_undo_file_seq{FlatFileSeq{m_opts.blocks_dir, "rev", UNDOFILE_CHUNK_SIZE}},
-      m_interrupt{interrupt} {}
+      m_interrupt{interrupt}
+{
+    m_block_tree_db = std::make_unique<BlockTreeDB>(m_opts.block_tree_db_params);
+
+    if (m_opts.block_tree_db_params.wipe_data) {
+        m_block_tree_db->WriteReindexing(true);
+        m_blockfiles_indexed = false;
+        // If we're reindexing in prune mode, wipe away unusable block files and all undo data files
+        if (m_prune_mode) {
+            CleanupBlockRevFiles();
+        }
+    }
+}
 
 class ImportingNow
 {

src/node/chainstate.cpp

@@ -23,10 +23,7 @@
 #include <validation.h>
 
 #include <algorithm>
-#include <atomic>
 #include <cassert>
-#include <limits>
-#include <memory>
 #include <vector>
 
 using kernel::CacheSizes;
@@ -36,34 +33,8 @@ namespace node {
 // to ChainstateManager::InitializeChainstate().
 static ChainstateLoadResult CompleteChainstateInitialization(
     ChainstateManager& chainman,
-    const CacheSizes& cache_sizes,
     const ChainstateLoadOptions& options) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
-    auto& pblocktree{chainman.m_blockman.m_block_tree_db};
-    // new BlockTreeDB tries to delete the existing file, which
-    // fails if it's still open from the previous loop. Close it first:
-    pblocktree.reset();
-    try {
-        pblocktree = std::make_unique<BlockTreeDB>(DBParams{
-            .path = chainman.m_options.datadir / "blocks" / "index",
-            .cache_bytes = cache_sizes.block_tree_db,
-            .memory_only = options.block_tree_db_in_memory,
-            .wipe_data = options.wipe_block_tree_db,
-            .options = chainman.m_options.block_tree_db});
-    } catch (dbwrapper_error& err) {
-        LogError("%s\n", err.what());
-        return {ChainstateLoadStatus::FAILURE, _("Error opening block database")};
-    }
-
-    if (options.wipe_block_tree_db) {
-        pblocktree->WriteReindexing(true);
-        chainman.m_blockman.m_blockfiles_indexed = false;
-        //If we're reindexing in prune mode, wipe away unusable block files and all undo data files
-        if (options.prune) {
-            chainman.m_blockman.CleanupBlockRevFiles();
-        }
-    }
-
     if (chainman.m_interrupt) return {ChainstateLoadStatus::INTERRUPTED, {}};
 
     // LoadBlockIndex will load m_have_pruned if we've ever removed a
@@ -155,14 +126,12 @@ static ChainstateLoadResult CompleteChainstateInitialization(
         }
     }
 
-    if (!options.wipe_block_tree_db) {
-        auto chainstates{chainman.GetAll()};
-        if (std::any_of(chainstates.begin(), chainstates.end(),
-                        [](const Chainstate* cs) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return cs->NeedsRedownload(); })) {
-            return {ChainstateLoadStatus::FAILURE, strprintf(_("Witness data for blocks after height %d requires validation. Please restart with -reindex."),
-                                                             chainman.GetConsensus().SegwitHeight)};
-        };
-    }
+    auto chainstates{chainman.GetAll()};
+    if (std::any_of(chainstates.begin(), chainstates.end(),
+                    [](const Chainstate* cs) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return cs->NeedsRedownload(); })) {
+        return {ChainstateLoadStatus::FAILURE, strprintf(_("Witness data for blocks after height %d requires validation. Please restart with -reindex."),
+                                                         chainman.GetConsensus().SegwitHeight)};
+    };
 
     // Now that chainstates are loaded and we're able to flush to
     // disk, rebalance the coins caches to desired levels based
@@ -208,7 +177,7 @@ ChainstateLoadResult LoadChainstate(ChainstateManager& chainman, const CacheSize
         }
     }
 
-    auto [init_status, init_error] = CompleteChainstateInitialization(chainman, cache_sizes, options);
+    auto [init_status, init_error] = CompleteChainstateInitialization(chainman, options);
     if (init_status != ChainstateLoadStatus::SUCCESS) {
         return {init_status, init_error};
     }
@@ -244,7 +213,7 @@ ChainstateLoadResult LoadChainstate(ChainstateManager& chainman, const CacheSize
         // for the fully validated chainstate.
         chainman.ActiveChainstate().ClearBlockIndexCandidates();
 
-        auto [init_status, init_error] = CompleteChainstateInitialization(chainman, cache_sizes, options);
+        auto [init_status, init_error] = CompleteChainstateInitialization(chainman, options);
         if (init_status != ChainstateLoadStatus::SUCCESS) {
             return {init_status, init_error};
         }

src/node/chainstate.h

@@ -22,12 +22,7 @@ namespace node {
 
 struct ChainstateLoadOptions {
     CTxMemPool* mempool{nullptr};
-    bool block_tree_db_in_memory{false};
     bool coins_db_in_memory{false};
-    // Whether to wipe the block tree database when loading it. If set, this
-    // will also set a reindexing flag so any existing block data files will be
-    // scanned and added to the database.
-    bool wipe_block_tree_db{false};
     // Whether to wipe the chainstate database when loading it. If set, this
     // will cause the chainstate database to be rebuilt starting from genesis.
     bool wipe_chainstate_db{false};

src/node/chainstatemanager_args.cpp

@@ -49,7 +49,6 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& args, ChainstateManage
 
     if (auto value{args.GetIntArg("-maxtipage")}) opts.max_tip_age = std::chrono::seconds{*value};
 
-    ReadDatabaseArgs(args, opts.block_tree_db);
     ReadDatabaseArgs(args, opts.coins_db);
     ReadCoinsViewArgs(args, opts.coins_view);
 

src/node/interfaces.cpp

@@ -46,6 +46,7 @@
 #include <policy/settings.h>
 #include <primitives/block.h>
 #include <primitives/transaction.h>
+#include <rpc/blockchain.h>
 #include <rpc/protocol.h>
 #include <rpc/server.h>
 #include <support/allocators/secure.h>
@@ -770,6 +771,11 @@ public:
         LOCK(::cs_main);
         return chainman().m_blockman.m_have_pruned;
     }
+    std::optional<int> getPruneHeight() override
+    {
+        LOCK(chainman().GetMutex());
+        return GetPruneHeight(chainman().m_blockman, chainman().ActiveChain());
+    }
     bool isReadyToBroadcast() override { return !chainman().m_blockman.LoadingBlocks() && !isInitialBlockDownload(); }
     bool isInitialBlockDownload() override
     {

src/node/miner.cpp

@@ -28,16 +28,25 @@
 #include <utility>
 
 namespace node {
+
+int64_t GetMinimumTime(const CBlockIndex* pindexPrev, const int64_t difficulty_adjustment_interval)
+{
+    int64_t min_time{pindexPrev->GetMedianTimePast() + 1};
+    // Height of block to be mined.
+    const int height{pindexPrev->nHeight + 1};
+    // Account for BIP94 timewarp rule on all networks. This makes future
+    // activation safer.
+    if (height % difficulty_adjustment_interval == 0) {
+        min_time = std::max<int64_t>(min_time, pindexPrev->GetBlockTime() - MAX_TIMEWARP);
+    }
+    return min_time;
+}
+
 int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
 {
     int64_t nOldTime = pblock->nTime;
-    int64_t nNewTime{std::max<int64_t>(pindexPrev->GetMedianTimePast() + 1, TicksSinceEpoch<std::chrono::seconds>(NodeClock::now()))};
-
-    // Height of block to be mined.
-    const int height{pindexPrev->nHeight + 1};
-    if (height % consensusParams.DifficultyAdjustmentInterval() == 0) {
-        nNewTime = std::max<int64_t>(nNewTime, pindexPrev->GetBlockTime() - MAX_TIMEWARP);
-    }
+    int64_t nNewTime{std::max<int64_t>(GetMinimumTime(pindexPrev, consensusParams.DifficultyAdjustmentInterval()),
+                                       TicksSinceEpoch<std::chrono::seconds>(NodeClock::now()))};
 
     if (nOldTime < nNewTime) {
         pblock->nTime = nNewTime;

src/node/miner.h

@@ -211,6 +211,13 @@ private:
     void SortForBlock(const CTxMemPool::setEntries& package, std::vector<CTxMemPool::txiter>& sortedEntries);
 };
 
+/**
+ * Get the minimum time a miner should use in the next block. This always
+ * accounts for the BIP94 timewarp rule, so does not necessarily reflect the
+ * consensus limit.
+ */
+int64_t GetMinimumTime(const CBlockIndex* pindexPrev, const int64_t difficulty_adjustment_interval);
+
 int64_t UpdateTime(CBlockHeader* pblock, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev);
 
 /** Update an old GenerateCoinbaseCommitment from CreateNewBlock after the block txs have changed */

src/rpc/mining.cpp

@@ -49,6 +49,7 @@
 using interfaces::BlockTemplate;
 using interfaces::Mining;
 using node::BlockAssembler;
+using node::GetMinimumTime;
 using node::NodeContext;
 using node::RegenerateCommitments;
 using node::UpdateTime;
@@ -674,7 +675,7 @@ static RPCHelpMan getblocktemplate()
                 {RPCResult::Type::NUM, "coinbasevalue", "maximum allowable input to coinbase transaction, including the generation award and transaction fees (in satoshis)"},
                 {RPCResult::Type::STR, "longpollid", "an id to include with a request to longpoll on an update to this template"},
                 {RPCResult::Type::STR, "target", "The hash target"},
-                {RPCResult::Type::NUM_TIME, "mintime", "The minimum timestamp appropriate for the next block time, expressed in " + UNIX_EPOCH_TIME},
+                {RPCResult::Type::NUM_TIME, "mintime", "The minimum timestamp appropriate for the next block time, expressed in " + UNIX_EPOCH_TIME + ". Adjusted for the proposed BIP94 timewarp rule."},
                 {RPCResult::Type::ARR, "mutable", "list of ways the block template may be changed",
                 {
                     {RPCResult::Type::STR, "value", "A way the block template may be changed, e.g. 'time', 'transactions', 'prevblock'"},
@@ -683,7 +684,7 @@ static RPCHelpMan getblocktemplate()
                 {RPCResult::Type::NUM, "sigoplimit", "limit of sigops in blocks"},
                 {RPCResult::Type::NUM, "sizelimit", "limit of block size"},
                 {RPCResult::Type::NUM, "weightlimit", /*optional=*/true, "limit of block weight"},
-                {RPCResult::Type::NUM_TIME, "curtime", "current timestamp in " + UNIX_EPOCH_TIME},
+                {RPCResult::Type::NUM_TIME, "curtime", "current timestamp in " + UNIX_EPOCH_TIME + ". Adjusted for the proposed BIP94 timewarp rule."},
                 {RPCResult::Type::STR, "bits", "compressed target of next block"},
                 {RPCResult::Type::NUM, "height", "The height of the next block"},
                 {RPCResult::Type::STR_HEX, "signet_challenge", /*optional=*/true, "Only on signet"},
@@ -977,7 +978,7 @@ static RPCHelpMan getblocktemplate()
     result.pushKV("coinbasevalue", (int64_t)block.vtx[0]->vout[0].nValue);
     result.pushKV("longpollid", tip.GetHex() + ToString(nTransactionsUpdatedLast));
     result.pushKV("target", hashTarget.GetHex());
-    result.pushKV("mintime", (int64_t)pindexPrev->GetMedianTimePast()+1);
+    result.pushKV("mintime", GetMinimumTime(pindexPrev, consensusParams.DifficultyAdjustmentInterval()));
     result.pushKV("mutable", std::move(aMutable));
     result.pushKV("noncerange", "00000000ffffffff");
     int64_t nSigOpLimit = MAX_BLOCK_SIGOPS_COST;

src/test/blockmanager_tests.cpp

@@ -33,6 +33,10 @@ BOOST_AUTO_TEST_CASE(blockmanager_find_block_pos)
         .chainparams = *params,
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = notifications,
+        .block_tree_db_params = DBParams{
+            .path = m_args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = 0,
+        },
     };
     BlockManager blockman{*Assert(m_node.shutdown_signal), blockman_opts};
     // simulate adding a genesis block normally
@@ -140,6 +144,10 @@ BOOST_AUTO_TEST_CASE(blockmanager_flush_block_file)
         .chainparams = Params(),
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = notifications,
+        .block_tree_db_params = DBParams{
+            .path = m_args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = 0,
+        },
     };
     BlockManager blockman{*Assert(m_node.shutdown_signal), blockman_opts};
 

src/test/fuzz/cluster_linearize.cpp

@@ -64,7 +64,6 @@ public:
         SetInfo best(m_depgraph, m_todo);
         // Process the queue.
         while (!queue.empty() && iterations_left) {
-            --iterations_left;
             // Pop top element of the queue.
             auto [inc, und] = queue.back();
             queue.pop_back();
@@ -75,6 +74,7 @@ public:
                 // transactions that share ancestry with inc so far (which means only connected
                 // sets will be considered).
                 if (inc_none || inc.Overlaps(m_depgraph.Ancestors(split))) {
+                    --iterations_left;
                     // Add a queue entry with split included.
                     SetInfo new_inc(m_depgraph, inc | (m_todo & m_depgraph.Ancestors(split)));
                     queue.emplace_back(new_inc.transactions, und - new_inc.transactions);
@@ -92,9 +92,8 @@ public:
 
 /** A very simple finder class for optimal candidate sets, which tries every subset.
  *
- * It is even simpler than SimpleCandidateFinder, and is primarily included here to test the
- * correctness of SimpleCandidateFinder, which is then used to test the correctness of
- * SearchCandidateFinder.
+ * It is even simpler than SimpleCandidateFinder, and exists just to help test the correctness of
+ * SimpleCandidateFinder, which is then used to test the correctness of SearchCandidateFinder.
  */
 template<typename SetType>
 class ExhaustiveCandidateFinder
@@ -185,12 +184,16 @@ void MakeConnected(DepGraph<BS>& depgraph)
 
 /** Given a dependency graph, and a todo set, read a topological subset of todo from reader. */
 template<typename SetType>
-SetType ReadTopologicalSet(const DepGraph<SetType>& depgraph, const SetType& todo, SpanReader& reader)
+SetType ReadTopologicalSet(const DepGraph<SetType>& depgraph, const SetType& todo, SpanReader& reader, bool non_empty)
 {
+    // Read a bitmask from the fuzzing input. Add 1 if non_empty, so the mask is definitely not
+    // zero in that case.
     uint64_t mask{0};
     try {
         reader >> VARINT(mask);
     } catch(const std::ios_base::failure&) {}
+    mask += non_empty;
+
     SetType ret;
     for (auto i : todo) {
         if (!ret[i]) {
@@ -198,7 +201,17 @@ SetType ReadTopologicalSet(const DepGraph<SetType>& depgraph, const SetType& tod
             mask >>= 1;
         }
     }
-    return ret & todo;
+    ret &= todo;
+
+    // While mask starts off non-zero if non_empty is true, it is still possible that all its low
+    // bits are 0, and ret ends up being empty. As a last resort, use the in-todo ancestry of the
+    // first todo position.
+    if (non_empty && ret.None()) {
+        Assume(todo.Any());
+        ret = depgraph.Ancestors(todo.First()) & todo;
+        Assume(ret.Any());
+    }
+    return ret;
 }
 
 /** Given a dependency graph, construct any valid linearization for it, reading from a SpanReader. */
@@ -581,10 +594,10 @@ FUZZ_TARGET(clusterlin_ancestor_finder)
         assert(real_best_anc.has_value());
         assert(*real_best_anc == best_anc);
 
-        // Find a topologically valid subset of transactions to remove from the graph.
-        auto del_set = ReadTopologicalSet(depgraph, todo, reader);
-        // If we did not find anything, use best_anc itself, because we should remove something.
-        if (del_set.None()) del_set = best_anc.transactions;
+        // Find a non-empty topologically valid subset of transactions to remove from the graph.
+        // Using an empty set would mean the next iteration is identical to the current one, and
+        // could cause an infinite loop.
+        auto del_set = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
         todo -= del_set;
         anc_finder.MarkDone(del_set);
     }
@@ -594,11 +607,99 @@ FUZZ_TARGET(clusterlin_ancestor_finder)
 
 static constexpr auto MAX_SIMPLE_ITERATIONS = 300000;
 
+FUZZ_TARGET(clusterlin_simple_finder)
+{
+    // Verify that SimpleCandidateFinder works as expected by sanity checking the results
+    // and comparing them (if claimed to be optimal) against the sets found by
+    // ExhaustiveCandidateFinder and AncestorCandidateFinder.
+    //
+    // Note that SimpleCandidateFinder is only used in tests; the purpose of this fuzz test is to
+    // establish confidence in SimpleCandidateFinder, so that it can be used to test
+    // SearchCandidateFinder below.
+
+    // Retrieve a depgraph from the fuzz input.
+    SpanReader reader(buffer);
+    DepGraph<TestBitSet> depgraph;
+    try {
+        reader >> Using<DepGraphFormatter>(depgraph);
+    } catch (const std::ios_base::failure&) {}
+
+    // Instantiate the SimpleCandidateFinder to be tested, and the ExhaustiveCandidateFinder and
+    // AncestorCandidateFinder it is being tested against.
+    SimpleCandidateFinder smp_finder(depgraph);
+    ExhaustiveCandidateFinder exh_finder(depgraph);
+    AncestorCandidateFinder anc_finder(depgraph);
+
+    auto todo = depgraph.Positions();
+    while (todo.Any()) {
+        assert(!smp_finder.AllDone());
+        assert(!exh_finder.AllDone());
+        assert(!anc_finder.AllDone());
+        assert(anc_finder.NumRemaining() == todo.Count());
+
+        // Call SimpleCandidateFinder.
+        auto [found, iterations_done] = smp_finder.FindCandidateSet(MAX_SIMPLE_ITERATIONS);
+        bool optimal = (iterations_done != MAX_SIMPLE_ITERATIONS);
+
+        // Sanity check the result.
+        assert(iterations_done <= MAX_SIMPLE_ITERATIONS);
+        assert(found.transactions.Any());
+        assert(found.transactions.IsSubsetOf(todo));
+        assert(depgraph.FeeRate(found.transactions) == found.feerate);
+        // Check that it is topologically valid.
+        for (auto i : found.transactions) {
+            assert(found.transactions.IsSupersetOf(depgraph.Ancestors(i) & todo));
+        }
+
+        // At most 2^(N-1) iterations can be required: the number of non-empty connected subsets a
+        // graph with N transactions can have. If MAX_SIMPLE_ITERATIONS exceeds this number, the
+        // result is necessarily optimal.
+        assert(iterations_done <= (uint64_t{1} << (todo.Count() - 1)));
+        if (MAX_SIMPLE_ITERATIONS > (uint64_t{1} << (todo.Count() - 1))) assert(optimal);
+
+        // Perform quality checks only if SimpleCandidateFinder claims an optimal result.
+        if (optimal) {
+            // Optimal sets are always connected.
+            assert(depgraph.IsConnected(found.transactions));
+
+            // Compare with AncestorCandidateFinder.
+            auto anc = anc_finder.FindCandidateSet();
+            assert(anc.feerate <= found.feerate);
+
+            if (todo.Count() <= 12) {
+                // Compare with ExhaustiveCandidateFinder. This quickly gets computationally
+                // expensive for large clusters (O(2^n)), so only do it for sufficiently small ones.
+                auto exhaustive = exh_finder.FindCandidateSet();
+                assert(exhaustive.feerate == found.feerate);
+            }
+
+            // Compare with a non-empty topological set read from the fuzz input (comparing with an
+            // empty set is not interesting).
+            auto read_topo = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
+            assert(found.feerate >= depgraph.FeeRate(read_topo));
+        }
+
+        // Find a non-empty topologically valid subset of transactions to remove from the graph.
+        // Using an empty set would mean the next iteration is identical to the current one, and
+        // could cause an infinite loop.
+        auto del_set = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
+        todo -= del_set;
+        smp_finder.MarkDone(del_set);
+        exh_finder.MarkDone(del_set);
+        anc_finder.MarkDone(del_set);
+    }
+
+    assert(smp_finder.AllDone());
+    assert(exh_finder.AllDone());
+    assert(anc_finder.AllDone());
+    assert(anc_finder.NumRemaining() == 0);
+}
+
 FUZZ_TARGET(clusterlin_search_finder)
 {
     // Verify that SearchCandidateFinder works as expected by sanity checking the results
-    // and comparing with the results from SimpleCandidateFinder, ExhaustiveCandidateFinder, and
-    // AncestorCandidateFinder.
+    // and comparing with the results from SimpleCandidateFinder and AncestorCandidateFinder,
+    // if the result is claimed to be optimal.
 
     // Retrieve an RNG seed, a depgraph, and whether to make it connected, from the fuzz input.
     SpanReader reader(buffer);
@@ -612,17 +713,15 @@ FUZZ_TARGET(clusterlin_search_finder)
     // the graph to be connected.
     if (make_connected) MakeConnected(depgraph);
 
-    // Instantiate ALL the candidate finders.
+    // Instantiate the candidate finders.
     SearchCandidateFinder src_finder(depgraph, rng_seed);
     SimpleCandidateFinder smp_finder(depgraph);
-    ExhaustiveCandidateFinder exh_finder(depgraph);
     AncestorCandidateFinder anc_finder(depgraph);
 
     auto todo = depgraph.Positions();
     while (todo.Any()) {
         assert(!src_finder.AllDone());
         assert(!smp_finder.AllDone());
-        assert(!exh_finder.AllDone());
         assert(!anc_finder.AllDone());
         assert(anc_finder.NumRemaining() == todo.Count());
 
@@ -633,11 +732,13 @@ FUZZ_TARGET(clusterlin_search_finder)
         } catch (const std::ios_base::failure&) {}
         max_iterations &= 0xfffff;
 
-        // Read an initial subset from the fuzz input.
-        SetInfo init_best(depgraph, ReadTopologicalSet(depgraph, todo, reader));
+        // Read an initial subset from the fuzz input (allowed to be empty).
+        auto init_set = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/false);
+        SetInfo init_best(depgraph, init_set);
 
         // Call the search finder's FindCandidateSet for what remains of the graph.
         auto [found, iterations_done] = src_finder.FindCandidateSet(max_iterations, init_best);
+        bool optimal = iterations_done < max_iterations;
 
         // Sanity check the result.
         assert(iterations_done <= max_iterations);
@@ -663,7 +764,7 @@ FUZZ_TARGET(clusterlin_search_finder)
         }
 
         // Perform quality checks only if SearchCandidateFinder claims an optimal result.
-        if (iterations_done < max_iterations) {
+        if (optimal) {
             // Optimal sets are always connected.
             assert(depgraph.IsConnected(found.transactions));
 
@@ -678,34 +779,24 @@ FUZZ_TARGET(clusterlin_search_finder)
             auto anc = anc_finder.FindCandidateSet();
             assert(found.feerate >= anc.feerate);
 
-            // Compare with ExhaustiveCandidateFinder. This quickly gets computationally expensive
-            // for large clusters (O(2^n)), so only do it for sufficiently small ones.
-            if (todo.Count() <= 12) {
-                auto exhaustive = exh_finder.FindCandidateSet();
-                assert(exhaustive.feerate == found.feerate);
-                // Also compare ExhaustiveCandidateFinder with SimpleCandidateFinder (this is
-                // primarily a test for SimpleCandidateFinder's correctness).
-                assert(exhaustive.feerate >= simple.feerate);
-                if (simple_iters < MAX_SIMPLE_ITERATIONS) {
-                    assert(exhaustive.feerate == simple.feerate);
-                }
-            }
+            // Compare with a non-empty topological set read from the fuzz input (comparing with an
+            // empty set is not interesting).
+            auto read_topo = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
+            assert(found.feerate >= depgraph.FeeRate(read_topo));
         }
 
-        // Find a topologically valid subset of transactions to remove from the graph.
-        auto del_set = ReadTopologicalSet(depgraph, todo, reader);
-        // If we did not find anything, use found itself, because we should remove something.
-        if (del_set.None()) del_set = found.transactions;
+        // Find a non-empty topologically valid subset of transactions to remove from the graph.
+        // Using an empty set would mean the next iteration is identical to the current one, and
+        // could cause an infinite loop.
+        auto del_set = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
         todo -= del_set;
         src_finder.MarkDone(del_set);
         smp_finder.MarkDone(del_set);
-        exh_finder.MarkDone(del_set);
         anc_finder.MarkDone(del_set);
     }
 
     assert(src_finder.AllDone());
     assert(smp_finder.AllDone());
-    assert(exh_finder.AllDone());
     assert(anc_finder.AllDone());
     assert(anc_finder.NumRemaining() == 0);
 }
@@ -721,9 +812,10 @@ FUZZ_TARGET(clusterlin_linearization_chunking)
         reader >> Using<DepGraphFormatter>(depgraph);
     } catch (const std::ios_base::failure&) {}
 
-    // Retrieve a topologically-valid subset of depgraph.
+    // Retrieve a topologically-valid subset of depgraph (allowed to be empty, because the argument
+    // to LinearizationChunking::Intersect is allowed to be empty).
     auto todo = depgraph.Positions();
-    auto subset = SetInfo(depgraph, ReadTopologicalSet(depgraph, todo, reader));
+    auto subset = SetInfo(depgraph, ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/false));
 
     // Retrieve a valid linearization for depgraph.
     auto linearization = ReadLinearization(depgraph, reader);
@@ -812,13 +904,10 @@ FUZZ_TARGET(clusterlin_linearization_chunking)
             }
         }
 
-        // Find a subset to remove from linearization.
-        auto done = ReadTopologicalSet(depgraph, todo, reader);
-        if (done.None()) {
-            // We need to remove a non-empty subset, so fall back to the unlinearized ancestors of
-            // the first transaction in todo if done is empty.
-            done = depgraph.Ancestors(todo.First()) & todo;
-        }
+        // Find a non-empty topologically valid subset of transactions to remove from the graph.
+        // Using an empty set would mean the next iteration is identical to the current one, and
+        // could cause an infinite loop.
+        auto done = ReadTopologicalSet(depgraph, todo, reader, /*non_empty=*/true);
         todo -= done;
         chunking.MarkDone(done);
         subset = SetInfo(depgraph, subset.transactions - done);
@@ -827,6 +916,76 @@ FUZZ_TARGET(clusterlin_linearization_chunking)
     assert(chunking.NumChunksLeft() == 0);
 }
 
+FUZZ_TARGET(clusterlin_simple_linearize)
+{
+    // Verify the behavior of SimpleLinearize(). Note that SimpleLinearize is only used in tests;
+    // the purpose of this fuzz test is to establish confidence in SimpleLinearize, so that it can
+    // be used to test the real Linearize function in the fuzz test below.
+
+    // Retrieve an iteration count and a depgraph from the fuzz input.
+    SpanReader reader(buffer);
+    uint64_t iter_count{0};
+    DepGraph<TestBitSet> depgraph;
+    try {
+        reader >> VARINT(iter_count) >> Using<DepGraphFormatter>(depgraph);
+    } catch (const std::ios_base::failure&) {}
+    iter_count %= MAX_SIMPLE_ITERATIONS;
+
+    // Invoke SimpleLinearize().
+    auto [linearization, optimal] = SimpleLinearize(depgraph, iter_count);
+    SanityCheck(depgraph, linearization);
+    auto simple_chunking = ChunkLinearization(depgraph, linearization);
+
+    // If the iteration count is sufficiently high, an optimal linearization must be found.
+    // SimpleLinearize on k transactions can take up to 2^(k-1) iterations (one per non-empty
+    // connected topologically valid subset), which sums over k=1..n to (2^n)-1.
+    const uint64_t n = depgraph.TxCount();
+    if (n <= 63 && (iter_count >> n)) {
+        assert(optimal);
+    }
+
+    // If SimpleLinearize claims optimal result, and the cluster is sufficiently small (there are
+    // n! linearizations), test that the result is as good as every valid linearization.
+    if (optimal && depgraph.TxCount() <= 8) {
+        std::vector<ClusterIndex> perm_linearization;
+        // Initialize with the lexicographically-first linearization.
+        for (ClusterIndex i : depgraph.Positions()) perm_linearization.push_back(i);
+        // Iterate over all valid permutations.
+        do {
+            /** What prefix of perm_linearization is topological. */
+            ClusterIndex topo_length{0};
+            TestBitSet perm_done;
+            while (topo_length < perm_linearization.size()) {
+                auto i = perm_linearization[topo_length];
+                perm_done.Set(i);
+                if (!depgraph.Ancestors(i).IsSubsetOf(perm_done)) break;
+                ++topo_length;
+            }
+            if (topo_length == perm_linearization.size()) {
+                // If all of perm_linearization is topological, verify that the obtained
+                // linearization is no worse than it.
+                auto perm_chunking = ChunkLinearization(depgraph, perm_linearization);
+                auto cmp = CompareChunks(simple_chunking, perm_chunking);
+                assert(cmp >= 0);
+            } else {
+                // Otherwise, fast forward to the last permutation with the same non-topological
+                // prefix.
+                auto first_non_topo = perm_linearization.begin() + topo_length;
+                assert(std::is_sorted(first_non_topo + 1, perm_linearization.end()));
+                std::reverse(first_non_topo + 1, perm_linearization.end());
+            }
+        } while(std::next_permutation(perm_linearization.begin(), perm_linearization.end()));
+    }
+
+    if (optimal) {
+        // Compare with a linearization read from the fuzz input.
+        auto read = ReadLinearization(depgraph, reader);
+        auto read_chunking = ChunkLinearization(depgraph, read);
+        auto cmp = CompareChunks(simple_chunking, read_chunking);
+        assert(cmp >= 0);
+    }
+}
+
 FUZZ_TARGET(clusterlin_linearize)
 {
     // Verify the behavior of Linearize().
@@ -903,30 +1062,11 @@ FUZZ_TARGET(clusterlin_linearize)
         // SimpleLinearize is broken).
         if (simple_optimal) assert(cmp == 0);
 
-        // Only for very small clusters, test every topologically-valid permutation.
-        if (depgraph.TxCount() <= 7) {
-            std::vector<ClusterIndex> perm_linearization;
-            for (ClusterIndex i : depgraph.Positions()) perm_linearization.push_back(i);
-            // Iterate over all valid permutations.
-            do {
-                // Determine whether perm_linearization is topological.
-                TestBitSet perm_done;
-                bool perm_is_topo{true};
-                for (auto i : perm_linearization) {
-                    perm_done.Set(i);
-                    if (!depgraph.Ancestors(i).IsSubsetOf(perm_done)) {
-                        perm_is_topo = false;
-                        break;
-                    }
-                }
-                // If so, verify that the obtained linearization is as good as the permutation.
-                if (perm_is_topo) {
-                    auto perm_chunking = ChunkLinearization(depgraph, perm_linearization);
-                    auto cmp = CompareChunks(chunking, perm_chunking);
-                    assert(cmp >= 0);
-                }
-            } while(std::next_permutation(perm_linearization.begin(), perm_linearization.end()));
-        }
+        // Compare with a linearization read from the fuzz input.
+        auto read = ReadLinearization(depgraph, reader);
+        auto read_chunking = ChunkLinearization(depgraph, read);
+        auto cmp_read = CompareChunks(chunking, read_chunking);
+        assert(cmp_read >= 0);
     }
 }
 

src/test/util/setup_common.cpp

@@ -62,7 +62,6 @@
 #include <stdexcept>
 
 using namespace util::hex_literals;
-using kernel::BlockTreeDB;
 using node::ApplyArgsManOptions;
 using node::BlockAssembler;
 using node::BlockManager;
@@ -252,14 +251,14 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, TestOpts opts)
             .chainparams = chainman_opts.chainparams,
             .blocks_dir = m_args.GetBlocksDirPath(),
             .notifications = chainman_opts.notifications,
+            .block_tree_db_params = DBParams{
+                .path = m_args.GetDataDirNet() / "blocks" / "index",
+                .cache_bytes = m_kernel_cache_sizes.block_tree_db,
+                .memory_only = opts.block_tree_db_in_memory,
+                .wipe_data = m_args.GetBoolArg("-reindex", false),
+            },
         };
         m_node.chainman = std::make_unique<ChainstateManager>(*Assert(m_node.shutdown_signal), chainman_opts, blockman_opts);
-        LOCK(m_node.chainman->GetMutex());
-        m_node.chainman->m_blockman.m_block_tree_db = std::make_unique<BlockTreeDB>(DBParams{
-            .path = m_args.GetDataDirNet() / "blocks" / "index",
-            .cache_bytes = m_kernel_cache_sizes.block_tree_db,
-            .memory_only = true,
-        });
     };
     m_make_chainman();
 }
@@ -285,9 +284,7 @@ void ChainTestingSetup::LoadVerifyActivateChainstate()
     auto& chainman{*Assert(m_node.chainman)};
     node::ChainstateLoadOptions options;
     options.mempool = Assert(m_node.mempool.get());
-    options.block_tree_db_in_memory = m_block_tree_db_in_memory;
     options.coins_db_in_memory = m_coins_db_in_memory;
-    options.wipe_block_tree_db = m_args.GetBoolArg("-reindex", false);
     options.wipe_chainstate_db = m_args.GetBoolArg("-reindex", false) || m_args.GetBoolArg("-reindex-chainstate", false);
     options.prune = chainman.m_blockman.IsPruneMode();
     options.check_blocks = m_args.GetIntArg("-checkblocks", DEFAULT_CHECKBLOCKS);

src/test/validation_chainstatemanager_tests.cpp

@@ -393,6 +393,11 @@ struct SnapshotTestSetup : TestChain100Setup {
                 .chainparams = chainman_opts.chainparams,
                 .blocks_dir = m_args.GetBlocksDirPath(),
                 .notifications = chainman_opts.notifications,
+                .block_tree_db_params = DBParams{
+                    .path = chainman.m_options.datadir / "blocks" / "index",
+                    .cache_bytes = m_kernel_cache_sizes.block_tree_db,
+                    .memory_only = m_block_tree_db_in_memory,
+                },
             };
             // For robustness, ensure the old manager is destroyed before creating a
             // new one.

src/validation.cpp

@@ -5623,9 +5623,8 @@ double ChainstateManager::GuessVerificationProgress(const CBlockIndex* pindex) c
         return 0.0;
     }
 
-    if (!Assume(pindex->m_chain_tx_count > 0)) {
-        LogWarning("Internal bug detected: block %d has unset m_chain_tx_count (%s %s). Please report this issue here: %s\n",
-                   pindex->nHeight, CLIENT_NAME, FormatFullVersion(), CLIENT_BUGREPORT);
+    if (pindex->m_chain_tx_count == 0) {
+        LogDebug(BCLog::VALIDATION, "Block %d has unset m_chain_tx_count. Unable to estimate verification progress.\n", pindex->nHeight);
         return 0.0;
     }
 

src/wallet/rpc/backup.cpp

@@ -1745,20 +1745,27 @@ RPCHelpMan importdescriptors()
                 if (scanned_time <= GetImportTimestamp(request, now) || results.at(i).exists("error")) {
                     response.push_back(results.at(i));
                 } else {
+                    std::string error_msg{strprintf("Rescan failed for descriptor with timestamp %d. There "
+                            "was an error reading a block from time %d, which is after or within %d seconds "
+                            "of key creation, and could contain transactions pertaining to the desc. As a "
+                            "result, transactions and coins using this desc may not appear in the wallet.",
+                            GetImportTimestamp(request, now), scanned_time - TIMESTAMP_WINDOW - 1, TIMESTAMP_WINDOW)};
+                    if (pwallet->chain().havePruned()) {
+                        error_msg += strprintf(" This error could be caused by pruning or data corruption "
+                                "(see bitcoind log for details) and could be dealt with by downloading and "
+                                "rescanning the relevant blocks (see -reindex option and rescanblockchain RPC).");
+                    } else if (pwallet->chain().hasAssumedValidChain()) {
+                        error_msg += strprintf(" This error is likely caused by an in-progress assumeutxo "
+                                "background sync. Check logs or getchainstates RPC for assumeutxo background "
+                                "sync progress and try again later.");
+                    } else {
+                        error_msg += strprintf(" This error could potentially caused by data corruption. If "
+                                "the issue persists you may want to reindex (see -reindex option).");
+                    }
+
                     UniValue result = UniValue(UniValue::VOBJ);
                     result.pushKV("success", UniValue(false));
-                    result.pushKV(
-                        "error",
-                        JSONRPCError(
-                            RPC_MISC_ERROR,
-                            strprintf("Rescan failed for descriptor with timestamp %d. There was an error reading a "
-                                      "block from time %d, which is after or within %d seconds of key creation, and "
-                                      "could contain transactions pertaining to the desc. As a result, transactions "
-                                      "and coins using this desc may not appear in the wallet. This error could be "
-                                      "caused by pruning or data corruption (see bitcoind log for details) and could "
-                                      "be dealt with by downloading and rescanning the relevant blocks (see -reindex "
-                                      "option and rescanblockchain RPC).",
-                                GetImportTimestamp(request, now), scanned_time - TIMESTAMP_WINDOW - 1, TIMESTAMP_WINDOW)));
+                    result.pushKV("error", JSONRPCError(RPC_MISC_ERROR, error_msg));
                     response.push_back(std::move(result));
                 }
             }

src/wallet/rpc/transactions.cpp

@@ -6,6 +6,7 @@
 #include <key_io.h>
 #include <policy/rbf.h>
 #include <rpc/util.h>
+#include <rpc/blockchain.h>
 #include <util/vector.h>
 #include <wallet/receive.h>
 #include <wallet/rpc/util.h>
@@ -909,9 +910,15 @@ RPCHelpMan rescanblockchain()
             }
         }
 
-        // We can't rescan beyond non-pruned blocks, stop and throw an error
+        // We can't rescan unavailable blocks, stop and throw an error
         if (!pwallet->chain().hasBlocks(pwallet->GetLastBlockHash(), start_height, stop_height)) {
-            throw JSONRPCError(RPC_MISC_ERROR, "Can't rescan beyond pruned data. Use RPC call getblockchaininfo to determine your pruned height.");
+            if (pwallet->chain().havePruned() && pwallet->chain().getPruneHeight() >= start_height) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Can't rescan beyond pruned data. Use RPC call getblockchaininfo to determine your pruned height.");
+            }
+            if (pwallet->chain().hasAssumedValidChain()) {
+                throw JSONRPCError(RPC_MISC_ERROR, "Failed to rescan unavailable blocks likely due to an in-progress assumeutxo background sync. Check logs or getchainstates RPC for assumeutxo background sync progress and try again later.");
+            }
+            throw JSONRPCError(RPC_MISC_ERROR, "Failed to rescan unavailable blocks, potentially caused by data corruption. If the issue persists you may want to reindex (see -reindex option).");
         }
 
         CHECK_NONFATAL(pwallet->chain().findAncestorByHeight(pwallet->GetLastBlockHash(), start_height, FoundBlock().hash(start_block)));

test/functional/mining_basic.py

@@ -153,6 +153,8 @@ class MiningTest(BitcoinTestFramework):
         # The template will have an adjusted timestamp, which we then modify
         tmpl = node.getblocktemplate(NORMAL_GBT_REQUEST_PARAMS)
         assert_greater_than_or_equal(tmpl['curtime'], t + MAX_FUTURE_BLOCK_TIME - MAX_TIMEWARP)
+        # mintime and curtime should match
+        assert_equal(tmpl['mintime'], tmpl['curtime'])
 
         block = CBlock()
         block.nVersion = tmpl["version"]

test/functional/rpc_blockchain.py

@@ -549,6 +549,7 @@ class BlockchainTest(BitcoinTestFramework):
         # The chain has probably already been restored by the time reconsiderblock returns,
         # but poll anyway.
         self.wait_until(lambda: node.waitfornewblock(timeout=100)['hash'] == current_hash)
+        assert_raises_rpc_error(-1, "Negative timeout", node.waitfornewblock, -1)
 
     def _test_waitforblockheight(self):
         self.log.info("Test waitforblockheight")

test/functional/wallet_assumeutxo.py

@@ -7,11 +7,11 @@ See feature_assumeutxo.py for background.
 
 ## Possible test improvements
 
-- TODO: test import descriptors while background sync is in progress
 - TODO: test loading a wallet (backup) on a pruned node
 
 """
 from test_framework.address import address_to_scriptpubkey
+from test_framework.descriptors import descsum_create
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.messages import COIN
 from test_framework.util import (
@@ -20,6 +20,7 @@ from test_framework.util import (
     ensure_for,
 )
 from test_framework.wallet import MiniWallet
+from test_framework.wallet_util import get_generate_key
 
 START_HEIGHT = 199
 SNAPSHOT_BASE_HEIGHT = 299
@@ -49,6 +50,13 @@ class AssumeutxoTest(BitcoinTestFramework):
         self.add_nodes(3)
         self.start_nodes(extra_args=self.extra_args)
 
+    def import_descriptor(self, node, wallet_name, key, timestamp):
+        import_request = [{"desc": descsum_create("pkh(" + key.pubkey + ")"),
+                           "timestamp": timestamp,
+                           "label": "Descriptor import test"}]
+        wrpc = node.get_wallet_rpc(wallet_name)
+        return wrpc.importdescriptors(import_request)
+
     def run_test(self):
         """
         Bring up two (disconnected) nodes, mine some new blocks on the first,
@@ -157,6 +165,21 @@ class AssumeutxoTest(BitcoinTestFramework):
         self.log.info("Backup from before the snapshot height can't be loaded during background sync")
         assert_raises_rpc_error(-4, "Wallet loading failed. Error loading wallet. Wallet requires blocks to be downloaded, and software does not currently support loading wallets while blocks are being downloaded out of order when using assumeutxo snapshots. Wallet should be able to load successfully after node sync reaches height 299", n1.restorewallet, "w2", "backup_w2.dat")
 
+        self.log.info("Test loading descriptors during background sync")
+        wallet_name = "w1"
+        n1.createwallet(wallet_name, disable_private_keys=True)
+        key = get_generate_key()
+        time = n1.getblockchaininfo()['time']
+        timestamp = 0
+        expected_error_message = f"Rescan failed for descriptor with timestamp {timestamp}. There was an error reading a block from time {time}, which is after or within 7200 seconds of key creation, and could contain transactions pertaining to the desc. As a result, transactions and coins using this desc may not appear in the wallet. This error is likely caused by an in-progress assumeutxo background sync. Check logs or getchainstates RPC for assumeutxo background sync progress and try again later."
+        result = self.import_descriptor(n1, wallet_name, key, timestamp)
+        assert_equal(result[0]['error']['code'], -1)
+        assert_equal(result[0]['error']['message'], expected_error_message)
+
+        self.log.info("Test that rescanning blocks from before the snapshot fails when blocks are not available from the background sync yet")
+        w1 = n1.get_wallet_rpc(wallet_name)
+        assert_raises_rpc_error(-1, "Failed to rescan unavailable blocks likely due to an in-progress assumeutxo background sync. Check logs or getchainstates RPC for assumeutxo background sync progress and try again later.", w1.rescanblockchain, 100)
+
         PAUSE_HEIGHT = FINAL_HEIGHT - 40
 
         self.log.info("Restarting node to stop at height %d", PAUSE_HEIGHT)
@@ -204,6 +227,11 @@ class AssumeutxoTest(BitcoinTestFramework):
         self.wait_until(lambda: len(n2.getchainstates()['chainstates']) == 1)
         ensure_for(duration=1, f=lambda: (n2.getbalance() == 34))
 
+        self.log.info("Ensuring descriptors can be loaded after background sync")
+        n1.loadwallet(wallet_name)
+        result = self.import_descriptor(n1, wallet_name, key, timestamp)
+        assert_equal(result[0]['success'], True)
+
 
 if __name__ == '__main__':
     AssumeutxoTest(__file__).main()