25903914664-1

// Copyright (C) 2013-2020 Blockstack PBC, a public benefit corporation
// Copyright (C) 2020-2026 Stacks Open Internet Foundation
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
use std::collections::HashSet;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
#[cfg(test)]
use std::sync::LazyLock;
use std::thread;
use std::time::{Duration, Instant};

use clarity::boot_util::boot_code_id;
use clarity::vm::costs::ExecutionCost;
use clarity::vm::types::PrincipalData;
use libsigner::v0::messages::{MinerSlotID, SignerMessage};
use libsigner::StackerDBSession;
use rand::{thread_rng, Rng};
use stacks::burnchains::{Burnchain, Txid};
use stacks::chainstate::burn::db::sortdb::SortitionDB;
use stacks::chainstate::burn::{BlockSnapshot, ConsensusHash};
use stacks::chainstate::coordinator::OnChainRewardSetProvider;
use stacks::chainstate::nakamoto::coordinator::load_nakamoto_reward_set;
use stacks::chainstate::nakamoto::miner::{NakamotoBlockBuilder, NakamotoTenureInfo};
use stacks::chainstate::nakamoto::staging_blocks::NakamotoBlockObtainMethod;
use stacks::chainstate::nakamoto::{NakamotoBlock, NakamotoChainState};
use stacks::chainstate::stacks::boot::{RewardSet, MINERS_NAME};
use stacks::chainstate::stacks::db::{StacksChainState, StacksHeaderInfo};
use stacks::chainstate::stacks::{
    CoinbasePayload, Error as ChainstateError, StacksTransaction, StacksTransactionSigner,
    TenureChangeCause, TenureChangePayload, TransactionAnchorMode, TransactionPayload,
    TransactionVersion,
};
use stacks::core::mempool::MemPoolWalkStrategy;
use stacks::net::api::poststackerdbchunk::StackerDBErrorCodes;
use stacks::net::p2p::NetworkHandle;
use stacks::net::stackerdb::StackerDBs;
use stacks::net::{NakamotoBlocksData, StacksMessageType};
use stacks::types::chainstate::BlockHeaderHash;
use stacks::types::{MinerDiagnosticData, MiningReason};
use stacks::util::get_epoch_time_secs;
use stacks::util::secp256k1::MessageSignature;
#[cfg(test)]
use stacks::util::secp256k1::Secp256k1PublicKey;
use stacks_common::types::chainstate::{StacksAddress, StacksBlockId};
#[cfg(test)]
use stacks_common::types::PublicKey;
use stacks_common::types::{PrivateKey, StacksEpochId};
#[cfg(test)]
use stacks_common::util::tests::TestFlag;
use stacks_common::util::vrf::VRFProof;
#[cfg(test)]
use tempfile::tempdir;

use super::miner_db::MinerDB;
use super::relayer::{MinerStopHandle, RelayerThread};
use super::{Config, Error as NakamotoNodeError, EventDispatcher, Keychain};
use crate::nakamoto_node::signer_coordinator::SignerCoordinator;
use crate::nakamoto_node::VRF_MOCK_MINER_KEY;
use crate::neon_node;
use crate::run_loop::nakamoto::Globals;
use crate::run_loop::RegisteredKey;

#[cfg(test)]
#[derive(Default, Clone, PartialEq)]
enum TestMineStall {
    #[default]
    NotStalled,
    Pending,
    Stalled,
}

#[cfg(test)]
/// Test flag to stall the miner thread
static TEST_MINE_STALL: LazyLock<TestFlag<TestMineStall>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
/// Test flag to stall block proposal broadcasting for the specified miner keys
pub static TEST_BROADCAST_PROPOSAL_STALL: LazyLock<TestFlag<Vec<Secp256k1PublicKey>>> =
    LazyLock::new(TestFlag::default);
#[cfg(test)]
/// Test flag to make miner skip mining a block
pub static TEST_MINE_SKIP: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
// Test flag to stall the miner from announcing a block while this flag is true
pub static TEST_BLOCK_ANNOUNCE_STALL: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
// Test flag to skip broadcasting blocks over the p2p network
pub static TEST_P2P_BROADCAST_SKIP: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
// Test flag to stall broadcasting blocks over the p2p network
pub static TEST_P2P_BROADCAST_STALL: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
// Test flag to skip pushing blocks to the signers
pub static TEST_BLOCK_PUSH_SKIP: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
#[cfg(test)]
// Test flag to indicate the block that the miner most recently tried to broadcast
pub static TEST_MINER_BROADCASTING_BLOCK: LazyLock<TestFlag<NakamotoBlock>> =
    LazyLock::new(TestFlag::default);

#[cfg(test)]
/// Set the `TEST_MINE_STALL` flag to `Pending` and block until the miner is stalled.
pub fn fault_injection_stall_miner() {
    if TEST_MINE_STALL.get() == TestMineStall::NotStalled {
        TEST_MINE_STALL.set(TestMineStall::Pending);
    }
    while TEST_MINE_STALL.get() != TestMineStall::Stalled {
        std::thread::sleep(std::time::Duration::from_millis(10));
    }
}

#[cfg(test)]
/// Set the `TEST_MINE_STALL` flag to `Pending` and do not block.
pub fn fault_injection_try_stall_miner() {
    let mut stall_lock = TEST_MINE_STALL.0.lock().unwrap();
    if stall_lock.as_ref().is_none() || stall_lock.as_ref() == Some(&TestMineStall::NotStalled) {
        *stall_lock = Some(TestMineStall::Pending);
    }
}

#[cfg(test)]
/// Unstall the miner by setting the `TEST_MINE_STALL` flag to `NotStalled`.
pub fn fault_injection_unstall_miner() {
    TEST_MINE_STALL.set(TestMineStall::NotStalled);
}

/// If the miner was interrupted while mining a block, how long should the
///  miner thread sleep before trying again?
const ABORT_TRY_AGAIN_MS: u64 = 200;

#[allow(clippy::large_enum_variant)]
#[derive(Debug)]
pub enum MinerDirective {
    /// The miner won sortition so they should begin a new tenure
    BeginTenure {
        /// This is the block ID of the first block in the parent tenure
        parent_tenure_start: StacksBlockId,
        /// This is the snapshot that this miner won, and will produce a tenure for
        election_block: BlockSnapshot,
        /// This is the snapshot that caused the relayer to initiate this event (may be different
        ///  than the election block in the case where the miner is trying to mine a late block).
        burnchain_tip: BlockSnapshot,
        /// This is `true` if the snapshot above is known not to be the the latest burnchain tip,
        /// but an ancestor of it (for example, the burnchain tip could be an empty flash block, but the
        /// miner may nevertheless need to produce a Stacks block with a BlockFound tenure-change
        /// transaction for the tenure began by winning `burnchain_tip`'s sortition).
        late: bool,
    },
    /// The miner should try to continue their tenure if they are the active miner
    ContinueTenure { new_burn_view: ConsensusHash },
    /// The miner did not win sortition
    StopTenure,
}

#[derive(PartialEq, Debug, Clone)]
/// Tenure info needed to construct a tenure change or tenure extend transaction
struct ParentTenureInfo {
    /// The number of blocks in the parent tenure
    parent_tenure_blocks: u64,
    /// The consensus hash of the parent tenure
    parent_tenure_consensus_hash: ConsensusHash,
}

/// Metadata required for beginning a new tenure
struct ParentStacksBlockInfo {
    /// Header metadata for the Stacks block we're going to build on top of
    stacks_parent_header: StacksHeaderInfo,
    /// nonce to use for this new block's coinbase transaction
    coinbase_nonce: u64,
    parent_tenure: Option<ParentTenureInfo>,
}

/// The reason the miner thread was spawned
#[derive(PartialEq, Clone, Debug)]
pub enum MinerReason {
    /// The miner thread was spawned to begin a new tenure
    BlockFound {
        /// `late` indicates whether or not the tenure that is about to be started corresponds to
        /// an ancestor of the canonical tip.  This can happen if this miner won the highest
        /// sortition, but that sortition's snapshot is not the canonical tip (e.g. the canonical
        /// tip may have no sortition, but its parent (or Nth ancestor) would have had a sortition
        /// that this miner won, and it would be the latest non-empty sortition ancestor of the
        /// tip).  This indication is important because the miner would issue a BlockFound
        /// tenure-change, and then issue an Extended tenure-change right afterwards in order to
        /// update the burnchain view exposed to Clarity for the highest sortition.
        late: bool,
    },
    /// The miner thread was spawned to extend an existing tenure
    Extended {
        /// Current consensus hash on the underlying burnchain.  Corresponds to the last-seen
        /// sortition.
        burn_view_consensus_hash: ConsensusHash,
    },
    /// Issue a read-count only extension
    ReadCountExtend {
        /// Current consensus hash on the underlying burnchain.  Corresponds to the last-seen
        /// sortition.
        burn_view_consensus_hash: ConsensusHash,
    },
}

impl MinerReason {
    pub fn is_late_block(&self) -> bool {
        match self {
            Self::BlockFound { ref late } => *late,
            Self::Extended { .. } => false,
            Self::ReadCountExtend { .. } => false,
        }
    }
}

impl std::fmt::Display for MinerReason {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            MinerReason::BlockFound { late } => {
                write!(f, "BlockFound({})", if *late { "late" } else { "current" })
            }
            MinerReason::Extended {
                burn_view_consensus_hash,
            } => write!(
                f,
                "Extended: burn_view_consensus_hash = {burn_view_consensus_hash:?}",
            ),
            MinerReason::ReadCountExtend {
                burn_view_consensus_hash,
            } => write!(
                f,
                "Read-Count Extend: burn_view_consensus_hash = {burn_view_consensus_hash:?}",
            ),
        }
    }
}

impl Into<MiningReason> for MinerReason {
    fn into(self) -> MiningReason {
        match self {
            Self::BlockFound { .. } => MiningReason::BlockFound,
            Self::Extended { .. } => MiningReason::Extended,
            Self::ReadCountExtend { .. } => MiningReason::ReadCountExtend,
        }
    }
}

pub struct BlockMinerThread {
    /// node config struct
    config: Config,
    /// handle to global state
    globals: Globals,
    /// copy of the node's keychain
    keychain: Keychain,
    /// burnchain configuration
    burnchain: Burnchain,
    /// Consensus hash and header hash of the last block mined
    last_block_mined: Option<(ConsensusHash, BlockHeaderHash)>,
    /// Number of blocks mined since a tenure change/extend was attempted
    mined_blocks: u64,
    /// Cost consumed by the current tenure
    tenure_cost: ExecutionCost,
    /// Cost budget for the current tenure
    tenure_budget: ExecutionCost,
    /// Copy of the node's registered VRF key
    registered_key: RegisteredKey,
    /// Burnchain block snapshot which elected this miner
    burn_election_block: BlockSnapshot,
    /// Current burnchain tip as of the last TenureChange
    /// * if the last tenure-change was a BlockFound, then this is the same as the
    /// `burn_election_block` (and it is also the `burn_view`)
    /// * otherwise, if the last tenure-change is an Extend, then this is the sortition of the burn
    /// view consensus hash in the TenureChange
    burn_block: BlockSnapshot,
    /// The start of the parent tenure for this tenure
    parent_tenure_id: StacksBlockId,
    /// Handle to the node's event dispatcher
    event_dispatcher: EventDispatcher,
    /// The reason the miner thread was spawned
    reason: MinerReason,
    /// Handle to the p2p thread for block broadcast
    p2p_handle: NetworkHandle,
    signer_set_cache: Option<RewardSet>,
    /// The time at which tenure change/extend was attempted
    tenure_change_time: Instant,
    /// The current tip when this miner thread was started.
    /// This *should not* be passed into any block building code, as it
    ///  is not necessarily the burn view for the block being constructed.
    /// Rather, this burn block is used to determine whether or not a new
    ///  burn block has arrived since this thread started.
    burn_tip_at_start: ConsensusHash,
    /// flag to indicate an abort driven from the relayer
    abort_flag: Arc<AtomicBool>,
    /// Should the nonce and considered transactions cache be reset before mining the next block?
    reset_mempool_caches: bool,
    /// Storage for persisting non-confidential miner information
    miner_db: MinerDB,
    /// Transaction IDs to exclude from the next block proposal only.
    /// Replaced (not accumulated) on each signer rejection.
    temporarily_excluded_txids: HashSet<Txid>,
    /// Transaction IDs to permanently ban from the mempool.
    /// Drained and blacklisted from the mempool in mine_block().
    permanently_excluded_txids: HashSet<Txid>,
}

/// Trait for the coordinator's read count extend timestamp check.
/// This trait is used so that we can unit test the function more easily.
trait ReadCountCheck {
    /// Get the timestamp at which at least 70% of the signing power should be
    /// willing to accept a time-based read-count extension.
    fn get_read_count_extend_timestamp(&self) -> u64;
}

impl ReadCountCheck for SignerCoordinator {
    fn get_read_count_extend_timestamp(&self) -> u64 {
        SignerCoordinator::get_read_count_extend_timestamp(self)
    }
}

impl BlockMinerThread {
    /// Instantiate the miner thread
    pub fn new(
        rt: &RelayerThread,
        registered_key: RegisteredKey,
        burn_election_block: BlockSnapshot,
        burn_block: BlockSnapshot,
        parent_tenure_id: StacksBlockId,
        burn_tip_at_start: &ConsensusHash,
        reason: MinerReason,
    ) -> Result<BlockMinerThread, NakamotoNodeError> {
        Ok(BlockMinerThread {
            config: rt.config.clone(),
            globals: rt.globals.clone(),
            keychain: rt.keychain.clone(),
            burnchain: rt.burnchain.clone(),
            last_block_mined: None,
            mined_blocks: 0,
            registered_key,
            burn_election_block,
            burn_block,
            event_dispatcher: rt.event_dispatcher.clone(),
            parent_tenure_id,
            reason,
            p2p_handle: rt.get_p2p_handle(),
            signer_set_cache: None,
            burn_tip_at_start: burn_tip_at_start.clone(),
            tenure_change_time: Instant::now(),
            abort_flag: Arc::new(AtomicBool::new(false)),
            tenure_cost: ExecutionCost::ZERO,
            tenure_budget: ExecutionCost::ZERO,
            reset_mempool_caches: true,
            miner_db: MinerDB::open_with_config(&rt.config)?,
            temporarily_excluded_txids: HashSet::new(),
            permanently_excluded_txids: HashSet::new(),
        })
    }

    pub fn get_abort_flag(&self) -> Arc<AtomicBool> {
        self.abort_flag.clone()
    }

    #[cfg(test)]
    fn fault_injection_block_proposal_stall(new_block: &NakamotoBlock) {
        if TEST_BROADCAST_PROPOSAL_STALL.get().iter().any(|key| {
            key.verify(
                new_block.header.miner_signature_hash().as_bytes(),
                &new_block.header.miner_signature,
            )
            .unwrap_or_default()
        }) {
            warn!("Fault injection: Block proposal broadcast is stalled due to testing directive.";
                        "stacks_block_id" => %new_block.block_id(),
                        "stacks_block_hash" => %new_block.header.block_hash(),
                        "height" => new_block.header.chain_length,
                        "consensus_hash" => %new_block.header.consensus_hash
            );
            while TEST_BROADCAST_PROPOSAL_STALL.get().iter().any(|key| {
                key.verify(
                    new_block.header.miner_signature_hash().as_bytes(),
                    &new_block.header.miner_signature,
                )
                .unwrap_or_default()
            }) {
                std::thread::sleep(std::time::Duration::from_millis(10));
            }
            info!("Fault injection: Block proposal broadcast is no longer stalled due to testing directive.";
                    "block_id" => %new_block.block_id(),
                    "height" => new_block.header.chain_length,
                    "consensus_hash" => %new_block.header.consensus_hash
            );
        }
    }

    #[cfg(not(test))]
    fn fault_injection_block_proposal_stall(_ignored: &NakamotoBlock) {}

    #[cfg(test)]
    fn fault_injection_block_mining_skip() -> bool {
        if TEST_MINE_SKIP.get() {
            warn!("Fault injection: Block mining is skipped due to testing directive.");
            true
        } else {
            false
        }
    }

    #[cfg(not(test))]
    fn fault_injection_block_mining_skip() -> bool {
        false
    }

    #[cfg(test)]
    fn fault_injection_block_announce_stall(new_block: &NakamotoBlock) {
        if TEST_BLOCK_ANNOUNCE_STALL.get() {
            // Do an extra check just so we don't log EVERY time.
            warn!("Fault injection: Block announcement is stalled due to testing directive.";
                      "stacks_block_id" => %new_block.block_id(),
                      "stacks_block_hash" => %new_block.header.block_hash(),
                      "height" => new_block.header.chain_length,
                      "consensus_hash" => %new_block.header.consensus_hash
            );
            while TEST_BLOCK_ANNOUNCE_STALL.get() {
                std::thread::sleep(std::time::Duration::from_millis(10));
            }
            info!("Fault injection: Block announcement is no longer stalled due to testing directive.";
                  "block_id" => %new_block.block_id(),
                  "height" => new_block.header.chain_length,
                  "consensus_hash" => %new_block.header.consensus_hash
            );
        }
    }

    #[cfg(not(test))]
    fn fault_injection_block_announce_stall(_ignored: &NakamotoBlock) {}

    #[cfg(test)]
    fn fault_injection_skip_block_broadcast() -> bool {
        TEST_P2P_BROADCAST_SKIP.get()
    }

    #[cfg(not(test))]
    fn fault_injection_skip_block_broadcast() -> bool {
        false
    }

    #[cfg(test)]
    fn fault_injection_block_broadcast_stall(new_block: &NakamotoBlock) {
        if TEST_P2P_BROADCAST_STALL.get() {
            // Do an extra check just so we don't log EVERY time.
            warn!("Fault injection: P2P block broadcast is stalled due to testing directive.";
                      "stacks_block_id" => %new_block.block_id(),
                      "stacks_block_hash" => %new_block.header.block_hash(),
                      "height" => new_block.header.chain_length,
                      "consensus_hash" => %new_block.header.consensus_hash
            );
            while TEST_P2P_BROADCAST_STALL.get() {
                std::thread::sleep(std::time::Duration::from_millis(10));
            }
            info!("Fault injection: P2P block broadcast is no longer stalled due to testing directive.";
                  "block_id" => %new_block.block_id(),
                  "height" => new_block.header.chain_length,
                  "consensus_hash" => %new_block.header.consensus_hash
            );
        }
    }

    #[cfg(not(test))]
    fn fault_injection_block_broadcast_stall(_ignored: &NakamotoBlock) {}

    #[cfg(test)]
    fn fault_injection_skip_block_push() -> bool {
        TEST_BLOCK_PUSH_SKIP.get()
    }

    #[cfg(not(test))]
    fn fault_injection_skip_block_push() -> bool {
        false
    }

    /// Stall the miner based on the `TEST_MINE_STALL` flag.
    /// Block the miner until the test flag is set to `NotStalled`.
    #[cfg(test)]
    fn fault_injection_miner_stall() {
        if TEST_MINE_STALL.get() != TestMineStall::NotStalled {
            // Do an extra check just so we don't log EVERY time.
            warn!("Mining is stalled due to testing directive");
            TEST_MINE_STALL.set(TestMineStall::Stalled);
            while TEST_MINE_STALL.get() != TestMineStall::NotStalled {
                std::thread::sleep(std::time::Duration::from_millis(10));
            }
            warn!("Mining is no longer stalled due to testing directive. Continuing...");
        }
    }

    #[cfg(not(test))]
    fn fault_injection_miner_stall() {}

    pub fn run_miner(
        mut self,
        prior_miner: Option<MinerStopHandle>,
    ) -> Result<(), NakamotoNodeError> {
        // when starting a new tenure, block the mining thread if its currently running.
        // the new mining thread will join it (so that the new mining thread stalls, not the relayer)
        debug!(
            "New miner thread starting";
            "had_prior_miner" => prior_miner.is_some(),
            "parent_tenure_id" => %self.parent_tenure_id,
            "thread_id" => ?thread::current().id(),
            "burn_block_consensus_hash" => %self.burn_block.consensus_hash,
            "burn_election_block_consensus_hash" => %self.burn_election_block.consensus_hash,
            "reason" => %self.reason,
        );
        if let Some(prior_miner) = prior_miner {
            debug!(
                "Miner thread {:?}: will try and stop prior miner {:?}",
                thread::current().id(),
                prior_miner.inner_thread().id()
            );
            prior_miner.stop(&self.globals)?;
        }
        let mut stackerdbs = StackerDBs::connect(&self.config.get_stacker_db_file_path(), true)?;
        let mut last_block_rejected = false;

        let reward_set = self.load_signer_set()?;
        let Some(miner_privkey) = self.config.miner.mining_key.clone() else {
            return Err(NakamotoNodeError::MinerConfigurationFailed(
                "No mining key configured, cannot mine",
            ));
        };
        let sortdb = SortitionDB::open(
            &self.config.get_burn_db_file_path(),
            true,
            self.burnchain.pox_constants.clone(),
            Some(self.config.node.get_marf_opts()),
        )
        .expect("FATAL: could not open sortition DB");

        // Start the signer coordinator
        let mut coordinator = SignerCoordinator::new(
            self.event_dispatcher.stackerdb_channel.clone(),
            self.globals.should_keep_running.clone(),
            &reward_set,
            &self.burn_election_block,
            &self.burnchain,
            miner_privkey,
            &self.config,
            &self.burn_tip_at_start,
        )
        .map_err(|e| {
            NakamotoNodeError::SigningCoordinatorFailure(format!(
                "Failed to initialize the signing coordinator. Cannot mine! {e:?}"
            ))
        })?;

        // now, actually run this tenure
        loop {
            if let Err(e) = self.attempt_mine_and_propose_block(
                &mut coordinator,
                &sortdb,
                &mut stackerdbs,
                &mut last_block_rejected,
                &reward_set,
            ) {
                // Before stopping this miner, shutdown the coordinator thread.
                coordinator.shutdown();
                return Err(e);
            }
        }
    }

    /// Pause the miner thread and retry to mine
    fn pause_and_retry(
        &self,
        new_block: &NakamotoBlock,
        last_block_rejected: &mut bool,
        e: &NakamotoNodeError,
    ) {
        // Sleep for a bit to allow signers to catch up
        let pause_ms = if *last_block_rejected {
            self.config.miner.subsequent_rejection_pause_ms
        } else {
            self.config.miner.first_rejection_pause_ms
        };

        error!("Error while gathering signatures: {e:?}. Will try mining again in {pause_ms}.";
            "signer_signature_hash" => %new_block.header.signer_signature_hash(),
            "block_height" => new_block.header.chain_length,
            "consensus_hash" => %new_block.header.consensus_hash,
        );
        thread::sleep(Duration::from_millis(pause_ms));
        *last_block_rejected = true;
    }

    /// Attempts to mine a block, propose it, and broadcast it if successful.
    ///
    /// Note: `Ok(())` does not guarantee that a block was mined, only that the
    /// mining attempt completed and a subsequent attempt should be tried
    ///
    /// Returns `Ok(())` if mining completes successfully or should be retried.
    /// Returns `Err` if the mining thread should exit (e.g., due to tenure changes or shutdown).
    fn attempt_mine_and_propose_block(
        &mut self,
        coordinator: &mut SignerCoordinator,
        sortdb: &SortitionDB,
        stackerdbs: &mut StackerDBs,
        last_block_rejected: &mut bool,
        reward_set: &RewardSet,
    ) -> Result<(), NakamotoNodeError> {
        Self::fault_injection_miner_stall();
        let mut chain_state =
            neon_node::open_chainstate_with_faults(&self.config).map_err(|e| {
                NakamotoNodeError::SigningCoordinatorFailure(format!(
                    "Failed to open chainstate DB. Cannot mine! {e:?}"
                ))
            })?;
        // Late block tenures are initiated only to issue the BlockFound
        //  tenure change tx (because they can be immediately extended to
        //  the next burn view). This checks whether or not we're in such a
        //  tenure and have produced a block already. If so, it exits the
        //  mining thread to allow the tenure extension thread to take over.
        if self.last_block_mined.is_some() && self.reason.is_late_block() {
            info!("Miner: finished mining a late tenure");
            return Err(NakamotoNodeError::StacksTipChanged);
        }
        // If we're mock mining, we may not have processed the block that the
        // actual tenure winner committed to yet. So, before attempting to
        // mock mine, check if the parent is processed.
        if self.config.get_node_config(false).mock_mining
            && !self.is_parent_processed(&mut chain_state)?
        {
            info!("Mock miner has not processed parent block yet, sleeping and trying again");
            thread::sleep(Duration::from_millis(ABORT_TRY_AGAIN_MS));
            return Ok(());
        }

        // Reset the mempool caches if needed. When mock-mining, we always
        // reset the caches, because the blocks we mine are not actually
        // processed, so the mempool caches are not valid.
        if self.reset_mempool_caches
            || self.config.miner.mempool_walk_strategy
                == MemPoolWalkStrategy::NextNonceWithHighestFeeRate
            || self.config.node.mock_mining
        {
            let mut mem_pool = self
                .config
                .connect_mempool_db()
                .expect("Database failure opening mempool");

            if self.reset_mempool_caches || self.config.node.mock_mining {
                mem_pool.reset_mempool_caches()?;
            } else {
                // Even if the nonce cache is still valid, NextNonceWithHighestFeeRate strategy
                // needs to reset this cache after each block. This prevents skipping transactions
                // that were previously considered, but not included in previous blocks.
                mem_pool.reset_considered_txs_cache()?;
            }
        }

        let Some(new_block) = self.mine_block_and_handle_result(coordinator)? else {
            // We should reattempt to mine
            return Ok(());
        };

        if !self.propose_new_block_and_broadcast(
            coordinator,
            sortdb,
            stackerdbs,
            last_block_rejected,
            reward_set,
            new_block,
        )? {
            // We should reattempt to mine
            return Ok(());
        }

        // Wait until the last block has been mined and processed
        self.wait_for_last_block_mined_and_processed(&mut chain_state)?;

        Ok(())
    }

    /// Check if the parent block has been processed
    fn is_parent_processed(
        &mut self,
        chain_state: &mut StacksChainState,
    ) -> Result<bool, NakamotoNodeError> {
        let burn_db_path = self.config.get_burn_db_file_path();
        let mut burn_db = SortitionDB::open(
            &burn_db_path,
            true,
            self.burnchain.pox_constants.clone(),
            Some(self.config.node.get_marf_opts()),
        )
        .expect("FATAL: could not open sortition DB");
        self.check_burn_tip_changed(&burn_db)?;
        match self.load_block_parent_info(&mut burn_db, chain_state) {
            Ok(..) => Ok(true),
            Err(NakamotoNodeError::ParentNotFound) => Ok(false),
            Err(e) => {
                warn!("Failed to load parent info: {e:?}");
                Err(e)
            }
        }
    }

    /// Attempts to mine a block and handle the result.
    ///
    /// - Returns `Ok(Some(NakamotoBlock))` if a block is successfully mined and passes timestamp validation.
    /// - Returns `Ok(None)` if mining should be retried (e.g. due to early block timestamp or no transactions).
    /// - Returns `Err(NakamotoNodeError)` if mining should be aborted (e.g. shutdown signal or unexpected error).
    fn mine_block_and_handle_result(
        &mut self,
        coordinator: &mut SignerCoordinator,
    ) -> Result<Option<NakamotoBlock>, NakamotoNodeError> {
        match self.mine_block(coordinator) {
            Ok(x) => {
                if !self.validate_timestamp(&x)? {
                    info!("Block mined too quickly. Will try again.";
                        "block_timestamp" => x.header.timestamp,
                    );
                    return Ok(None);
                }
                Ok(Some(x))
            }
            Err(NakamotoNodeError::MiningFailure(ChainstateError::MinerAborted)) => {
                if self.abort_flag.load(Ordering::SeqCst) {
                    info!("Miner interrupted while mining in order to shut down");
                    self.globals
                        .raise_initiative(format!("MiningFailure: aborted by node"));
                    return Err(ChainstateError::MinerAborted.into());
                }

                info!("Miner interrupted while mining, will try again");

                // sleep, and try again. if the miner was interrupted because the burnchain
                // view changed, the next `mine_block()` invocation will error
                thread::sleep(Duration::from_millis(ABORT_TRY_AGAIN_MS));
                Ok(None)
            }
            Err(NakamotoNodeError::MiningFailure(ChainstateError::NoTransactionsToMine)) => {
                debug!(
                    "Miner did not find any transactions to mine, sleeping for {:?}",
                    self.config.miner.empty_mempool_sleep_time
                );
                self.reset_mempool_caches = false;

                // Pause the miner to wait for transactions to arrive
                let now = Instant::now();
                while now.elapsed() < self.config.miner.empty_mempool_sleep_time {
                    if self.abort_flag.load(Ordering::SeqCst) {
                        info!("Miner interrupted while mining in order to shut down");
                        self.globals
                            .raise_initiative(format!("MiningFailure: aborted by node"));
                        return Err(ChainstateError::MinerAborted.into());
                    }

                    // Check if the burnchain tip has changed
                    let Ok(sort_db) = SortitionDB::open(
                        &self.config.get_burn_db_file_path(),
                        false,
                        self.burnchain.pox_constants.clone(),
                        Some(self.config.node.get_marf_opts()),
                    ) else {
                        error!("Failed to open sortition DB. Will try mining again.");
                        return Ok(None);
                    };
                    if self.check_burn_tip_changed(&sort_db).is_err() {
                        return Err(NakamotoNodeError::BurnchainTipChanged);
                    }

                    thread::sleep(Duration::from_millis(ABORT_TRY_AGAIN_MS));
                }
                Ok(None)
            }
            Err(NakamotoNodeError::ParentNotFound) if self.config.node.mock_mining => {
                info!(
                    "Mock miner could not load parent tenure info yet. Will try again.";
                );
                thread::sleep(Duration::from_millis(ABORT_TRY_AGAIN_MS));
                Ok(None)
            }
            Err(e) => {
                warn!("Failed to mine block: {e:?}");

                // try again, in case a new sortition is pending
                self.globals
                    .raise_initiative(format!("MiningFailure: {e:?}"));
                Err(ChainstateError::MinerAborted.into())
            }
        }
    }

    /// Attempts to propose a new block and broadcast it upon success.
    ///
    /// - Returns `Ok(true)` if the block was successfully proposed and broadcasted.
    /// - Returns `Ok(false)` if the proposal failed but the miner should retry (e.g. due to tip change or recoverable upload error).
    /// - Returns `Err(NakamotoNodeError)` if the operation should be aborted (e.g. unrecoverable error during proposal or broadcasting).
    fn propose_new_block_and_broadcast(
        &mut self,
        coordinator: &mut SignerCoordinator,
        sortdb: &SortitionDB,
        stackerdbs: &mut StackerDBs,
        last_block_rejected: &mut bool,
        reward_set: &RewardSet,
        mut new_block: NakamotoBlock,
    ) -> Result<bool, NakamotoNodeError> {
        Self::fault_injection_block_proposal_stall(&new_block);

        let signer_signature = match self.propose_block(
            coordinator,
            &mut new_block,
            sortdb,
            stackerdbs,
        ) {
            Ok(x) => x,
            Err(e) => match e {
                NakamotoNodeError::StacksTipChanged => {
                    info!("Stacks tip changed while waiting for signatures";
                        "signer_signature_hash" => %new_block.header.signer_signature_hash(),
                        "block_height" => new_block.header.chain_length,
                        "consensus_hash" => %new_block.header.consensus_hash,
                    );
                    return Ok(false);
                }
                NakamotoNodeError::BurnchainTipChanged => {
                    info!("Burnchain tip changed while waiting for signatures";
                        "signer_signature_hash" => %new_block.header.signer_signature_hash(),
                        "block_height" => new_block.header.chain_length,
                        "consensus_hash" => %new_block.header.consensus_hash,
                    );
                    return Err(e);
                }
                NakamotoNodeError::StackerDBUploadError(ref ack) => {
                    if ack.code == Some(StackerDBErrorCodes::BadSigner.code()) {
                        error!("Error while gathering signatures: failed to upload miner StackerDB data: {ack:?}. Giving up.";
                            "signer_signature_hash" => %new_block.header.signer_signature_hash(),
                            "block_height" => new_block.header.chain_length,
                            "consensus_hash" => %new_block.header.consensus_hash,
                        );
                        return Err(e);
                    }
                    self.pause_and_retry(&new_block, last_block_rejected, &e);
                    return Ok(false);
                }
                NakamotoNodeError::SignersRejected {
                    ref temporarily_excluded_txids,
                    ref permanently_excluded_txids,
                } => {
                    // Replace (not extend) temporarily_excluded_txids so the ban
                    // only applies to the next block proposal — transient failures
                    // may resolve after one block.
                    self.temporarily_excluded_txids = temporarily_excluded_txids.clone();
                    // Permanently excluded txids will be blacklisted from the
                    // mempool when mine_block opens the mempool connection.
                    self.permanently_excluded_txids
                        .extend(permanently_excluded_txids.iter().cloned());
                    self.pause_and_retry(&new_block, last_block_rejected, &e);
                    return Ok(false);
                }
                _ => {
                    self.pause_and_retry(&new_block, last_block_rejected, &e);
                    return Ok(false);
                }
            },
        };
        *last_block_rejected = false;

        new_block.header.signer_signature = signer_signature;
        if let Err(e) = self.broadcast(new_block.clone(), reward_set, stackerdbs) {
            warn!("Error accepting own block: {e:?}. Will try mining again.");
            return Ok(false);
        } else {
            info!(
                "Miner: Block signed by signer set and broadcasted";
                "signer_signature_hash" => %new_block.header.signer_signature_hash(),
                "stacks_block_hash" => %new_block.header.block_hash(),
                "stacks_block_id" => %new_block.header.block_id(),
                "block_height" => new_block.header.chain_length,
                "consensus_hash" => %new_block.header.consensus_hash,
            );

            // We successfully mined, so the mempool caches are valid.
            self.reset_mempool_caches = false;
            // Block was accepted — clear any single-block exclusions
            self.temporarily_excluded_txids.clear();
        }

        // update mined-block counters and mined-tenure counters
        self.globals.counters.bump_naka_mined_blocks();
        if self.last_block_mined.is_none() {
            // this is the first block of the tenure, bump tenure counter
            self.globals.counters.bump_naka_mined_tenures();
        }

        // wake up chains coordinator
        Self::fault_injection_block_announce_stall(&new_block);
        self.globals.coord().announce_new_stacks_block();

        self.last_block_mined = Some((
            new_block.header.consensus_hash.clone(),
            new_block.header.block_hash(),
        ));
        self.mined_blocks += 1;
        Ok(true)
    }

    /// Blocks until the most recently mined block has been fully processed by the chainstate
    /// and the miner is unblocked.
    ///
    /// - Returns `Ok(())` when the block is processed and the miner is ready to continue.
    /// - Returns `Err(NakamotoNodeError)` if mining is aborted or the chainstate is inconsistent.
    fn wait_for_last_block_mined_and_processed(
        &mut self,
        chain_state: &mut StacksChainState,
    ) -> Result<(), NakamotoNodeError> {
        let Some((last_consensus_hash, last_bhh)) = &self.last_block_mined else {
            return Ok(());
        };

        // If mock-mining, we don't need to wait for the last block to be
        // processed (because it will never be). Instead just wait
        // `min_time_between_blocks_ms`, then resume mining.
        if self.config.node.mock_mining {
            thread::sleep(Duration::from_millis(
                self.config.miner.min_time_between_blocks_ms,
            ));
            return Ok(());
        }

        loop {
            let (_, processed, _, _) = chain_state
                .nakamoto_blocks_db()
                .get_block_processed_and_signed_weight(last_consensus_hash, &last_bhh)?
                .ok_or_else(|| NakamotoNodeError::UnexpectedChainState)?;

            // Once the block has been processed and the miner is no longer
            // blocked, we can continue mining.
            if processed
                && !(*self
                    .globals
                    .get_miner_status()
                    .lock()
                    .expect("FATAL: mutex poisoned"))
                .is_blocked()
            {
                return Ok(());
            }

            thread::sleep(Duration::from_millis(ABORT_TRY_AGAIN_MS));

            if self.abort_flag.load(Ordering::SeqCst) {
                info!("Miner interrupted while mining in order to shut down");
                self.globals
                    .raise_initiative(format!("MiningFailure: aborted by node"));
                return Err(ChainstateError::MinerAborted.into());
            }

            // Check if the burnchain tip has changed
            let Ok(sort_db) = SortitionDB::open(
                &self.config.get_burn_db_file_path(),
                false,
                self.burnchain.pox_constants.clone(),
                Some(self.config.node.get_marf_opts()),
            ) else {
                error!("Failed to open sortition DB. Will try mining again.");
                return Ok(());
            };
            if self.check_burn_tip_changed(&sort_db).is_err() {
                return Err(NakamotoNodeError::BurnchainTipChanged);
            }
        }
    }

    fn propose_block(
        &self,
        coordinator: &mut SignerCoordinator,
        new_block: &mut NakamotoBlock,
        sortdb: &SortitionDB,
        stackerdbs: &mut StackerDBs,
    ) -> Result<Vec<MessageSignature>, NakamotoNodeError> {
        if self.config.get_node_config(false).mock_mining {
            // If we're mock mining, we don't actually propose the block.
            return Ok(Vec::new());
        }

        let mut chain_state =
            neon_node::open_chainstate_with_faults(&self.config).map_err(|e| {
                NakamotoNodeError::SigningCoordinatorFailure(format!(
                    "Failed to open chainstate DB. Cannot mine! {e:?}"
                ))
            })?;

        let burn_tip = SortitionDB::get_canonical_burn_chain_tip(sortdb.conn()).map_err(|e| {
            NakamotoNodeError::SigningCoordinatorFailure(format!(
                "Failed to open sortition DB. Cannot mine! {e:?}"
            ))
        })?;

        let diagnostics = MinerDiagnosticData {
            burnchain_tip_height: burn_tip.block_height,
            burnchain_tip_consensus_hash: burn_tip.consensus_hash,
            burnchain_tip_header_hash: burn_tip.burn_header_hash,
            tenure_extend_time_stamp: coordinator.get_tenure_extend_timestamp(),
            read_count_extend_timestamp: coordinator.get_read_count_extend_timestamp(),
            mining_reason: self.reason.clone().into(),
        };

        coordinator.propose_block(
            new_block,
            &self.burnchain,
            sortdb,
            &mut chain_state,
            stackerdbs,
            &self.globals.counters,
            &self.burn_election_block,
            &self.miner_db,
            diagnostics,
        )
    }

    /// Load the signer set active for this miner's blocks. This is the
    ///  active reward set during `self.burn_election_block`. The miner
    ///  thread caches this information, and this method will consult
    ///  that cache (or populate it if necessary).
    fn load_signer_set(&mut self) -> Result<RewardSet, NakamotoNodeError> {
        if let Some(set) = self.signer_set_cache.as_ref() {
            return Ok(set.clone());
        }
        let sort_db = SortitionDB::open(
            &self.config.get_burn_db_file_path(),
            true,
            self.burnchain.pox_constants.clone(),
            Some(self.config.node.get_marf_opts()),
        )
        .map_err(|e| {
            NakamotoNodeError::SigningCoordinatorFailure(format!(
                "Failed to open sortition DB. Cannot mine! {e:?}"
            ))
        })?;

        let mut chain_state =
            neon_node::open_chainstate_with_faults(&self.config).map_err(|e| {
                NakamotoNodeError::SigningCoordinatorFailure(format!(
                    "Failed to open chainstate DB. Cannot mine! {e:?}"
                ))
            })?;

        let burn_election_height = self.burn_election_block.block_height;

        let reward_cycle = self
            .burnchain
            .block_height_to_reward_cycle(burn_election_height)
            .expect("FATAL: no reward cycle for sortition");

        let reward_info = match load_nakamoto_reward_set(
            reward_cycle,
            &self.burn_election_block.sortition_id,
            &self.burnchain,
            &mut chain_state,
            &self.parent_tenure_id,
            &sort_db,
            &OnChainRewardSetProvider::new(),
        ) {
            Ok(Some((reward_info, _))) => reward_info,
            Ok(None) => {
                return Err(NakamotoNodeError::SigningCoordinatorFailure(
                    "No reward set stored yet. Cannot mine!".into(),
                ));
            }
            Err(e) => {
                return Err(NakamotoNodeError::SigningCoordinatorFailure(format!(
                    "Failure while fetching reward set. Cannot initialize miner coordinator. {e:?}"
                )));
            }
        };

        let Some(reward_set) = reward_info.known_selected_anchor_block_owned() else {
            return Err(NakamotoNodeError::SigningCoordinatorFailure(
                "Current reward cycle did not select a reward set. Cannot mine!".into(),
            ));
        };

        self.signer_set_cache = Some(reward_set.clone());
        Ok(reward_set)
    }

    /// Fault injection -- possibly fail to broadcast
    /// Return true to drop the block
    fn fault_injection_broadcast_fail(&self) -> bool {
        let drop_prob = self
            .config
            .node
            .fault_injection_block_push_fail_probability
            .unwrap_or(0)
            .min(100);
        if drop_prob > 0 {
            let throw: u8 = thread_rng().gen_range(0..100);
            throw < drop_prob
        } else {
            false
        }
    }

    /// Store a block to the chainstate, and if successful (it should be since we mined it),
    /// broadcast it via the p2p network.
    fn broadcast_p2p(
        &mut self,
        sort_db: &SortitionDB,
        chain_state: &mut StacksChainState,
        block: &NakamotoBlock,
        reward_set: &RewardSet,
    ) -> Result<(), ChainstateError> {
        if Self::fault_injection_skip_block_broadcast() {
            warn!(
                "Fault injection: Skipping block broadcast for {}",
                block.block_id()
            );
            return Ok(());
        }
        #[cfg(test)]
        TEST_MINER_BROADCASTING_BLOCK.set(block.clone());

        Self::fault_injection_block_broadcast_stall(block);

        let parent_block_info =
            NakamotoChainState::get_block_header(chain_state.db(), &block.header.parent_block_id)?
                .ok_or_else(|| ChainstateError::NoSuchBlockError)?;
        let burn_view_ch =
            NakamotoChainState::get_block_burn_view(sort_db, block, &parent_block_info)?;
        let mut sortition_handle = sort_db.index_handle_at_ch(&burn_view_ch)?;
        let accepted = NakamotoChainState::accept_block(
            chain_state,
            block,
            &mut sortition_handle,
            reward_set,
            NakamotoBlockObtainMethod::Mined,
        )?;

        if !accepted {
            // this can happen if the p2p network and relayer manage to receive this block prior to
            // the thread reaching this point -- this can happen because the signers broadcast the
            // signed block to the nodes independent of the miner, so the miner itself can receive
            // and store its own block outside of this thread.
            debug!("Did NOT accept block {} we mined", &block.block_id());

            // not much we can do here, but try and mine again and hope we produce a valid one.
            return Ok(());
        }

        // forward to p2p thread, but do fault injection
        if self.fault_injection_broadcast_fail() {
            info!("Fault injection: drop block {}", &block.block_id());
            return Ok(());
        }

        let block_id = block.block_id();
        debug!("Broadcasting block {block_id}");
        if let Err(e) = self.p2p_handle.broadcast_message(
            vec![],
            StacksMessageType::NakamotoBlocks(NakamotoBlocksData {
                blocks: vec![block.clone()],
            }),
        ) {
            warn!("Failed to broadcast block {block_id}: {e:?}");
        }
        Ok(())
    }

    fn broadcast(
        &mut self,
        block: NakamotoBlock,
        reward_set: &RewardSet,
        stackerdbs: &StackerDBs,
    ) -> Result<(), NakamotoNodeError> {
        if self.config.get_node_config(false).mock_mining {
            // If we're mock mining, we don't actually broadcast the block.
            return Ok(());
        }

        if self.config.miner.mining_key.is_none() {
            return Err(NakamotoNodeError::MinerConfigurationFailed(
                "No mining key configured, cannot mine",
            ));
        };

        let mut chain_state = neon_node::open_chainstate_with_faults(&self.config)
            .expect("FATAL: could not open chainstate DB");
        let sort_db = SortitionDB::open(
            &self.config.get_burn_db_file_path(),
            true,
            self.burnchain.pox_constants.clone(),
            Some(self.config.node.get_marf_opts()),
        )
        .expect("FATAL: could not open sortition DB");

        // push block via p2p block push
        self.broadcast_p2p(&sort_db, &mut chain_state, &block, reward_set)
            .map_err(NakamotoNodeError::AcceptFailure)?;

        let Some(ref miner_privkey) = self.config.miner.mining_key else {
            // should be unreachable, but we can't borrow this above broadcast_p2p() since it's
            // mutable
            return Err(NakamotoNodeError::MinerConfigurationFailed(
                "No mining key configured, cannot mine",
            ));
        };

        // also, push block via stackerdb to make sure stackers get it
        let rpc_socket = self.config.node.get_rpc_loopback().ok_or_else(|| {
            NakamotoNodeError::MinerConfigurationFailed("Failed to get RPC loopback socket")
        })?;
        let miners_contract_id = boot_code_id(MINERS_NAME, chain_state.mainnet);
        let mut miners_session = StackerDBSession::new(
            &rpc_socket.to_string(),
            miners_contract_id,
            self.config.miner.stackerdb_timeout,
        );

        if Self::fault_injection_skip_block_push() {
            warn!(
                "Fault injection: Skipping block push for {}",
                block.block_id()
            );
            return Ok(());
        }

        SignerCoordinator::send_miners_message(
            miner_privkey,
            &sort_db,
            &self.burn_block,
            stackerdbs,
            SignerMessage::BlockPushed(block),
            MinerSlotID::BlockPushed,
            chain_state.mainnet,
            &mut miners_session,
            &self.burn_election_block.consensus_hash,
            &self.miner_db,
        )
    }

    /// Get the coinbase recipient address, if set in the config and if allowed in this epoch
    fn get_coinbase_recipient(&self, epoch_id: StacksEpochId) -> Option<PrincipalData> {
        if epoch_id < StacksEpochId::Epoch21 && self.config.miner.block_reward_recipient.is_some() {
            warn!("Coinbase pay-to-contract is not supported in the current epoch");
            None
        } else {
            self.config.miner.block_reward_recipient.clone()
        }
    }

    fn generate_tenure_change_tx(
        &self,
        nonce: u64,
        payload: TenureChangePayload,
    ) -> StacksTransaction {
        let is_mainnet = self.config.is_mainnet();
        let chain_id = self.config.burnchain.chain_id;
        let tenure_change_tx_payload = TransactionPayload::TenureChange(payload);

        let mut tx_auth = self.keychain.get_transaction_auth().unwrap();
        tx_auth.set_origin_nonce(nonce);

        let version = if is_mainnet {
            TransactionVersion::Mainnet
        } else {
            TransactionVersion::Testnet
        };

        let mut tx = StacksTransaction::new(version, tx_auth, tenure_change_tx_payload);

        tx.chain_id = chain_id;
        tx.anchor_mode = TransactionAnchorMode::OnChainOnly;
        let mut tx_signer = StacksTransactionSigner::new(&tx);
        self.keychain.sign_as_origin(&mut tx_signer);

        tx_signer.get_tx().unwrap()
    }

    /// Create a coinbase transaction.
    fn generate_coinbase_tx(
        &self,
        nonce: u64,
        epoch_id: StacksEpochId,
        vrf_proof: VRFProof,
    ) -> StacksTransaction {
        let is_mainnet = self.config.is_mainnet();
        let chain_id = self.config.burnchain.chain_id;
        let mut tx_auth = self.keychain.get_transaction_auth().unwrap();
        tx_auth.set_origin_nonce(nonce);

        let version = if is_mainnet {
            TransactionVersion::Mainnet
        } else {
            TransactionVersion::Testnet
        };

        let recipient_opt = self.get_coinbase_recipient(epoch_id);

        let mut tx = StacksTransaction::new(
            version,
            tx_auth,
            TransactionPayload::Coinbase(
                CoinbasePayload([0u8; 32]),
                recipient_opt,
                Some(vrf_proof),
            ),
        );
        tx.chain_id = chain_id;
        tx.anchor_mode = TransactionAnchorMode::OnChainOnly;
        let mut tx_signer = StacksTransactionSigner::new(&tx);
        self.keychain.sign_as_origin(&mut tx_signer);

        tx_signer.get_tx().unwrap()
    }

    #[cfg_attr(test, mutants::skip)]
    /// Load up the parent block header for mining the next block.
    /// If we can't find the parent in the DB but we expect one, return Err(ParentNotFound).
    ///
    /// The nakamoto miner must always build off of a chain tip that is either:
    /// 1. The highest block in our own tenure
    /// 2. The highest block in our tenure's parent tenure (i.e., `self.parent_tenure_id`)
    ///
    /// `self.parent_tenure_id` is the tenure start block which was
    /// committed to by our tenure's associated block commit.
    fn load_block_parent_header(
        &self,
        burn_db: &mut SortitionDB,
        chain_state: &mut StacksChainState,
    ) -> Result<StacksHeaderInfo, NakamotoNodeError> {
        let my_tenure_tip = self
            .find_highest_known_block_in_my_tenure(&burn_db, &chain_state)
            .map_err(|e| {
                error!(
                    "Could not find highest header info for miner's tenure {}: {e:?}",
                    &self.burn_election_block.consensus_hash
                );
                NakamotoNodeError::ParentNotFound
            })?;
        if let Some(my_tenure_tip) = my_tenure_tip {
            debug!(
                "Stacks block parent ID is last block in tenure ID {}",
                &my_tenure_tip.consensus_hash
            );
            return Ok(my_tenure_tip);
        }

        // My tenure is empty on the canonical fork, so our parent should be the highest block in
        //   self.parent_tenure_id
        debug!(
            "Stacks block parent ID is last block in parent tenure tipped by {}",
            &self.parent_tenure_id
        );

        // find the last block in the parent tenure, since this is the tip we'll build atop
        let parent_tenure_header =
            NakamotoChainState::get_block_header(chain_state.db(), &self.parent_tenure_id)
                .map_err(|e| {
                    error!(
                        "Could not query header for parent tenure ID {}: {e:?}",
                        &self.parent_tenure_id
                    );
                    NakamotoNodeError::ParentNotFound
                })?
                .ok_or_else(|| {
                    error!("No header for parent tenure ID {}", &self.parent_tenure_id);
                    NakamotoNodeError::ParentNotFound
                })?;

        let header_opt = NakamotoChainState::find_highest_known_block_header_in_tenure(
            &chain_state,
            burn_db,
            &parent_tenure_header.consensus_hash,
        )
        .map_err(|e| {
            error!("Could not query parent tenure finish block: {e:?}");
            NakamotoNodeError::ParentNotFound
        })?;

        if let Some(parent_tenure_tip) = header_opt {
            return Ok(parent_tenure_tip);
        }

        // this is an epoch2 block
        debug!(
            "Stacks block parent ID is an epoch2x block: {}",
            &self.parent_tenure_id
        );

        Ok(parent_tenure_header)
    }

    // TODO: add tests from mutation testing results #4869
    #[cfg_attr(test, mutants::skip)]
    /// Load up the parent block info for mining.
    /// If we can't find the parent in the DB but we expect one, return Err(ParentNotFound).
    fn load_block_parent_info(
        &self,
        burn_db: &mut SortitionDB,
        chain_state: &mut StacksChainState,
    ) -> Result<ParentStacksBlockInfo, NakamotoNodeError> {
        let stacks_tip_header = self.load_block_parent_header(burn_db, chain_state)?;

        debug!(
            "Miner: stacks tip parent header is {} {stacks_tip_header:?}",
            &stacks_tip_header.index_block_hash()
        );
        let miner_address = self
            .keychain
            .origin_address(self.config.is_mainnet())
            .unwrap();
        ParentStacksBlockInfo::lookup(
            chain_state,
            burn_db,
            &self.burn_block,
            miner_address,
            &self.parent_tenure_id,
            stacks_tip_header,
            &self.reason,
        )
        .inspect_err(|e| {
            if matches!(e, NakamotoNodeError::BurnchainTipChanged) {
                self.globals.counters.bump_missed_tenures();
            }
        })
    }

    /// Generate the VRF proof for the block we're going to build.
    /// Returns Some(proof) if we could make the proof
    /// Return None if we could not make the proof
    fn make_vrf_proof(&mut self) -> Option<VRFProof> {
        // if we're a mock miner, then make sure that the keychain has a keypair for the mocked VRF
        // key
        let vrf_proof = if self.config.get_node_config(false).mock_mining {
            self.keychain.generate_proof(
                VRF_MOCK_MINER_KEY,
                self.burn_election_block.sortition_hash.as_bytes(),
            )
        } else {
            self.keychain.generate_proof(
                self.registered_key.target_block_height,
                self.burn_election_block.sortition_hash.as_bytes(),
            )
        };

        let Some(vrf_proof) = vrf_proof else {
            error!(
                "Unable to generate VRF proof, will be unable to mine";
                "burn_block_sortition_hash" => %self.burn_election_block.sortition_hash,
                "burn_block_block_height" => %self.burn_block.block_height,
                "burn_block_hash" => %self.burn_block.burn_header_hash,
                "vrf_pubkey" => &self.registered_key.vrf_public_key.to_hex()
            );
            return None;
        };

        debug!(
            "Generated VRF Proof: {} over {} ({},{}) with key {}",
            vrf_proof.to_hex(),
            &self.burn_election_block.sortition_hash,
            &self.burn_block.block_height,
            &self.burn_block.burn_header_hash,
            &self.registered_key.vrf_public_key.to_hex()
        );
        Some(vrf_proof)
    }

    fn validate_timestamp_info(
        &self,
        current_timestamp_secs: u64,
        stacks_parent_header: &StacksHeaderInfo,
    ) -> bool {
        let parent_timestamp = match stacks_parent_header.anchored_header.as_stacks_nakamoto() {
            Some(naka_header) => naka_header.timestamp,
            None => stacks_parent_header.burn_header_timestamp,
        };
        let time_since_parent_ms = current_timestamp_secs.saturating_sub(parent_timestamp) * 1000;
        if time_since_parent_ms < self.config.miner.min_time_between_blocks_ms {
            debug!("Parent block mined {time_since_parent_ms} ms ago. Required minimum gap between blocks is {} ms", self.config.miner.min_time_between_blocks_ms;
                "current_timestamp" => current_timestamp_secs,
                "parent_block_id" => %stacks_parent_header.index_block_hash(),
                "parent_block_height" => stacks_parent_header.stacks_block_height,
                "parent_block_timestamp" => stacks_parent_header.burn_header_timestamp,
            );
            false
        } else {
            true
        }
    }

    /// Check that the provided block is not mined too quickly after the parent block.
    /// This is to ensure that the signers do not reject the block due to the block being mined within the same second as the parent block.
    fn validate_timestamp(&self, x: &NakamotoBlock) -> Result<bool, NakamotoNodeError> {
        let chain_state = neon_node::open_chainstate_with_faults(&self.config)
            .expect("FATAL: could not open chainstate DB");
        let stacks_parent_header =
            NakamotoChainState::get_block_header(chain_state.db(), &x.header.parent_block_id)
                .map_err(|e| {
                    error!(
                        "Could not query header info for parent block ID {}: {e:?}",
                        &x.header.parent_block_id
                    );
                    NakamotoNodeError::ParentNotFound
                })?
                .ok_or_else(|| {
                    error!(
                        "No header info for parent block ID {}",
                        &x.header.parent_block_id
                    );
                    NakamotoNodeError::ParentNotFound
                })?;
        Ok(self.validate_timestamp_info(x.header.timestamp, &stacks_parent_header))
    }

    // TODO: add tests from mutation testing results #4869
    #[cfg_attr(test, mutants::skip)]
    /// Try to mine a Stacks block by assembling one from mempool transactions and sending a
    /// burnchain block-commit transaction.  If we succeed, then return the assembled block.
    fn mine_block(
        &mut self,
        coordinator: &mut SignerCoordinator,
    ) -> Result<NakamotoBlock, NakamotoNodeError> {
        debug!("block miner thread ID is {:?}", thread::current().id());
        info!("Miner: Mining block");

        let burn_db_path = self.config.get_burn_db_file_path();
        let reward_set = self.load_signer_set()?;

        // NOTE: read-write access is needed in order to be able to query the recipient set.
        // This is an artifact of the way the MARF is built (see #1449)
        let mut burn_db = SortitionDB::open(
            &burn_db_path,
            true,
            self.burnchain.pox_constants.clone(),
            Some(self.config.node.get_marf_opts()),
        )
        .expect("FATAL: could not open sortition DB");

        let mut chain_state = neon_node::open_chainstate_with_faults(&self.config)
            .expect("FATAL: could not open chainstate DB");

        self.check_burn_tip_changed(&burn_db)?;
        if Self::fault_injection_block_mining_skip() {
            return Err(ChainstateError::MinerAborted.into());
        }
        neon_node::fault_injection_long_tenure();

        let mut mem_pool = self
            .config
            .connect_mempool_db()
            .expect("Database failure opening mempool");

        // Blacklist permanently excluded transactions reported by signers
        if !self.permanently_excluded_txids.is_empty() {
            let txids: Vec<Txid> = self.permanently_excluded_txids.drain().collect();
            info!("Miner: blacklisting permanently excluded transaction(s) from mempool";
                "count" => txids.len(),
            );
            if let Err(e) = mem_pool.drop_and_blacklist_txs(&txids) {
                warn!("Miner: failed to blacklist permanently excluded transactions: {e:?}");
            }
        }

        let target_epoch_id =
            SortitionDB::get_stacks_epoch(burn_db.conn(), self.burn_block.block_height + 1)
                .map_err(|_| NakamotoNodeError::SnapshotNotFoundForChainTip)?
                .expect("FATAL: no epoch defined")
                .epoch_id;
        let mut parent_block_info = self.load_block_parent_info(&mut burn_db, &mut chain_state)?;
        let vrf_proof = self
            .make_vrf_proof()
            .ok_or_else(|| NakamotoNodeError::BadVrfConstruction)?;

        if self.config.node.mock_mining {
            if let Some((last_block_consensus_hash, _)) = &self.last_block_mined {
                // If we're mock mining, we need to manipulate the `last_block_mined`
                // to match what it should be based on the actual chainstate.
                if last_block_consensus_hash
                    == &parent_block_info.stacks_parent_header.consensus_hash
                {
                    // If the parent block is in the same tenure, then we should
                    // pretend that we mined it.
                    self.last_block_mined = Some((
                        parent_block_info
                            .stacks_parent_header
                            .consensus_hash
                            .clone(),
                        parent_block_info
                            .stacks_parent_header
                            .anchored_header
                            .block_hash(),
                    ));
                } else {
                    // If the parent block is not in the same tenure, then we
                    // should act as though we haven't mined anything yet.
                    self.last_block_mined = None;
                }
            }
        }

        if self.last_block_mined.is_none() && parent_block_info.parent_tenure.is_none() {
            if self.config.node.mock_mining {
                info!("Mock miner will follow canonical tip within an ongoing tenure; no parent tenure info loaded yet");
            } else {
                warn!(
                    "Miner should be starting a new tenure, but failed to load parent tenure info"
                );
                return Err(NakamotoNodeError::ParentNotFound);
            }
        };

        // create our coinbase if this is the first block we've mined this tenure
        let tenure_start_info = self.make_tenure_start_info(
            &chain_state,
            &parent_block_info,
            vrf_proof,
            target_epoch_id,
            coordinator,
        )?;

        parent_block_info.stacks_parent_header.microblock_tail = None;

        // Length of the per-block `pox_treatment` BitVec.
        // Must be `> 0`:
        //   the BitVec codec rejects zero-length bitvecs at deserialization.
        let signer_bitvec_len = reward_set.pox_treatment_bitvec_len();

        if !self.validate_timestamp_info(
            get_epoch_time_secs(),
            &parent_block_info.stacks_parent_header,
        ) {
            // treat a too-soon-to-mine block as an interrupt: this will let the caller sleep and then re-evaluate
            //  all the pre-mining checks (burnchain tip changes, signal interrupts, etc.)
            return Err(ChainstateError::MinerAborted.into());
        }

        // If we attempt to build a block, we should reset the nonce cache.
        // In the special case where no transactions are found, this flag will
        // be reset to false.
        self.reset_mempool_caches = true;

        let replay_transactions = if self.config.miner.replay_transactions {
            coordinator
                .get_signer_global_state()
                .map(|state| state.tx_replay_set.unwrap_or_default())
                .unwrap_or_default()
        } else {
            vec![]
        };
        // build the block itself
        let mining_burn_handle = burn_db
            .index_handle_at_ch(&self.burn_block.consensus_hash)
            .map_err(|_| NakamotoNodeError::UnexpectedChainState)?;
        if let Some(parent_burn_view) = &parent_block_info.stacks_parent_header.burn_view {
            if !mining_burn_handle.processed_block(parent_burn_view)? {
                error!(
                    "Cannot mine block: calculated parent has burn view which is incompatible with the canonical burn fork";
                    "parent_burn_view" => %parent_burn_view,
                    "my_burn_view" => %self.burn_block.consensus_hash,
                );
                return Err(NakamotoNodeError::BurnchainTipChanged);
            }
        }

        let mut block_metadata = NakamotoBlockBuilder::build_nakamoto_block(
            &chain_state,
            &mining_burn_handle,
            &mut mem_pool,
            &parent_block_info.stacks_parent_header,
            &self.burn_election_block.consensus_hash,
            self.burn_block.total_burn,
            tenure_start_info,
            {
                let mut settings = self
                    .config
                    .make_nakamoto_block_builder_settings(self.globals.get_miner_status());
                if !self.temporarily_excluded_txids.is_empty() {
                    info!("Miner: excluding signer-rejected transaction(s) from block building";
                        "count" => self.temporarily_excluded_txids.len(),
                    );
                    settings.temporarily_excluded_txids = self.temporarily_excluded_txids.clone();
                }
                settings
            },
            // we'll invoke the event dispatcher ourselves so that it calculates the
            //  correct signer_signature_hash for `process_mined_nakamoto_block_event`
            Some(&self.event_dispatcher),
            signer_bitvec_len,
            &replay_transactions,
        )
        .map_err(|e| {
            if !matches!(
                e,
                ChainstateError::MinerAborted | ChainstateError::NoTransactionsToMine
            ) {
                error!("Relayer: Failure mining anchored block: {e}");
            }
            e
        })?;

        if block_metadata.block.txs.is_empty() {
            return Err(ChainstateError::NoTransactionsToMine.into());
        }
        let mining_key = self.keychain.get_nakamoto_sk();
        let miner_signature = mining_key
            .sign(
                block_metadata
                    .block
                    .header
                    .miner_signature_hash()
                    .as_bytes(),
            )
            .map_err(NakamotoNodeError::MinerSignatureError)?;
        block_metadata.block.header.miner_signature = miner_signature;

        info!(
            "Miner: Assembled block #{} for signer set proposal: {}, with {} txs",
            block_metadata.block.header.chain_length,
            block_metadata.block.header.block_hash(),
            block_metadata.block.txs.len();
            "signer_signature_hash" => %block_metadata.block.header.signer_signature_hash(),
            "consensus_hash" => %block_metadata.block.header.consensus_hash,
            "parent_block_id" => %block_metadata.block.header.parent_block_id,
            "timestamp" => block_metadata.block.header.timestamp,
        );

        self.event_dispatcher.process_mined_nakamoto_block_event(
            self.burn_block.block_height,
            &block_metadata.block,
            block_metadata.tenure_size,
            &block_metadata.tenure_consumed,
            block_metadata.tx_events,
        );

        self.tenure_cost = block_metadata.tenure_consumed;
        self.tenure_budget = block_metadata.tenure_budget;

        // last chance -- confirm that the stacks tip is unchanged (since it could have taken long
        // enough to build this block that another block could have arrived), and confirm that all
        // Stacks blocks with heights higher than the canonical tip are processed.
        self.check_burn_tip_changed(&burn_db)?;
        Ok(block_metadata.block)
    }

    fn find_highest_known_block_in_my_tenure(
        &self,
        burn_db: &SortitionDB,
        chainstate: &StacksChainState,
    ) -> Result<Option<StacksHeaderInfo>, NakamotoNodeError> {
        NakamotoChainState::find_highest_known_block_header_in_tenure(
            chainstate,
            burn_db,
            &self.burn_election_block.consensus_hash,
        )
        .map_err(NakamotoNodeError::from)
    }

    fn should_full_tenure_extend(
        &self,
        coordinator: &mut SignerCoordinator,
    ) -> Result<bool, NakamotoNodeError> {
        if self.last_block_mined.is_none() {
            // if we haven't mined blocks yet, no tenure extends needed
            return Ok(false);
        }
        let is_replay = self.config.miner.replay_transactions
            && coordinator
                .get_signer_global_state()
                .map(|state| state.tx_replay_set.is_some())
                .unwrap_or(false);
        if is_replay {
            // we're in replay, we should always TenureExtend
            info!("Tenure extend: In replay, always extending tenure");
            return Ok(true);
        }

        // Do not extend if we have spent a threshold amount of the
        // budget, since it is not necessary.
        let usage = self
            .tenure_budget
            .proportion_largest_dimension(&self.tenure_cost);
        if usage < self.config.miner.tenure_extend_cost_threshold {
            return Ok(false);
        }

        let tenure_extend_timestamp = coordinator.get_tenure_extend_timestamp();
        if get_epoch_time_secs() <= tenure_extend_timestamp
            && self.tenure_change_time.elapsed() <= self.config.miner.tenure_timeout
        {
            return Ok(false);
        }

        info!("Miner: Time-based tenure extend";
              "current_timestamp" => get_epoch_time_secs(),
              "tenure_extend_timestamp" => tenure_extend_timestamp,
              "tenure_change_time_elapsed" => self.tenure_change_time.elapsed().as_secs(),
              "tenure_timeout_secs" => self.config.miner.tenure_timeout.as_secs(),
        );
        Ok(true)
    }

    fn should_read_count_extend<C: ReadCountCheck>(
        &self,
        coordinator: &C,
    ) -> Result<bool, NakamotoNodeError> {
        if self.last_block_mined.is_none() {
            // if we haven't mined blocks yet, no tenure extends needed
            return Ok(false);
        }

        // Do not extend if we have spent a threshold amount of the
        // read-count budget, since it is not necessary.
        let usage =
            self.tenure_cost.read_count / std::cmp::max(1, self.tenure_budget.read_count / 100);

        if usage < self.config.miner.read_count_extend_cost_threshold {
            info!(
                "Miner: not read-count extending because threshold not reached";
                "threshold" => self.config.miner.read_count_extend_cost_threshold,
                "usage" => usage
            );
            return Ok(false);
        }

        let tenure_extend_timestamp = coordinator.get_read_count_extend_timestamp();
        if get_epoch_time_secs() <= tenure_extend_timestamp {
            info!(
                "Miner: not read-count extending because idle timestamp not reached";
                "now" => get_epoch_time_secs(),
                "extend_ts" => tenure_extend_timestamp,
            );
            return Ok(false);
        }

        info!("Miner: Time-based read-count extend";
              "current_timestamp" => get_epoch_time_secs(),
              "tenure_extend_timestamp" => tenure_extend_timestamp,
              "tenure_change_time_elapsed" => self.tenure_change_time.elapsed().as_secs(),
              "tenure_timeout_secs" => self.config.miner.tenure_timeout.as_secs(),
        );
        Ok(true)
    }

    #[cfg_attr(test, mutants::skip)]
    /// Create the tenure start info for the block we're going to build
    fn make_tenure_start_info(
        &mut self,
        chainstate: &StacksChainState,
        parent_block_info: &ParentStacksBlockInfo,
        vrf_proof: VRFProof,
        target_epoch_id: StacksEpochId,
        coordinator: &mut SignerCoordinator,
    ) -> Result<NakamotoTenureInfo, NakamotoNodeError> {
        let current_miner_nonce = parent_block_info.coinbase_nonce;
        let parent_tenure_info = match &parent_block_info.parent_tenure {
            Some(info) => info.clone(),
            None => {
                // We may be able to extend the current tenure
                if self.last_block_mined.is_none() {
                    debug!("Miner: No parent tenure and no last block mined");
                    return Ok(NakamotoTenureInfo {
                        coinbase_tx: None,
                        tenure_change_tx: None,
                    });
                }
                ParentTenureInfo {
                    parent_tenure_blocks: self.mined_blocks,
                    parent_tenure_consensus_hash: self.burn_election_block.consensus_hash.clone(),
                }
            }
        };
        if self.last_block_mined.is_some() {
            // if we've already mined blocks, we only issue tenure_change_txs in the case of an extend,
            //  so check if that's necessary and otherwise return None.
            if self.should_full_tenure_extend(coordinator)? {
                self.set_full_tenure_extend();
            } else if self.should_read_count_extend(coordinator)? {
                self.set_read_count_tenure_extend();
            } else {
                return Ok(NakamotoTenureInfo {
                    coinbase_tx: None,
                    tenure_change_tx: None,
                });
            }
        }

        let parent_block_id = parent_block_info.stacks_parent_header.index_block_hash();
        let mut payload = TenureChangePayload {
            tenure_consensus_hash: self.burn_election_block.consensus_hash.clone(),
            prev_tenure_consensus_hash: parent_tenure_info.parent_tenure_consensus_hash.clone(),
            burn_view_consensus_hash: self.burn_election_block.consensus_hash.clone(),
            previous_tenure_end: parent_block_id.clone(),
            previous_tenure_blocks: u32::try_from(parent_tenure_info.parent_tenure_blocks)
                .expect("FATAL: more than u32 blocks in a tenure"),
            cause: TenureChangeCause::BlockFound,
            pubkey_hash: self.keychain.get_nakamoto_pkh(),
        };

        let (tenure_change_tx, coinbase_tx) = match &self.reason {
            MinerReason::BlockFound { .. } => {
                let tenure_change_tx = self.generate_tenure_change_tx(current_miner_nonce, payload);
                let coinbase_tx =
                    self.generate_coinbase_tx(current_miner_nonce + 1, target_epoch_id, vrf_proof);
                (Some(tenure_change_tx), Some(coinbase_tx))
            }
            MinerReason::Extended {
                burn_view_consensus_hash,
            } => {
                let num_blocks_so_far = NakamotoChainState::get_nakamoto_tenure_length(
                    chainstate.db(),
                    &parent_block_id,
                )
                .map_err(NakamotoNodeError::MiningFailure)?;
                info!("Miner: Extending tenure";
                      "burn_view_consensus_hash" => %burn_view_consensus_hash,
                      "parent_block_id" => %parent_block_id,
                      "num_blocks_so_far" => num_blocks_so_far,
                );

                // NOTE: this switches payload.cause to TenureChangeCause::Extend
                payload = payload.extend(
                    burn_view_consensus_hash.clone(),
                    parent_block_id,
                    num_blocks_so_far,
                );
                let tenure_change_tx = self.generate_tenure_change_tx(current_miner_nonce, payload);
                (Some(tenure_change_tx), None)
            }
            MinerReason::ReadCountExtend {
                burn_view_consensus_hash,
            } => {
                let num_blocks_so_far = NakamotoChainState::get_nakamoto_tenure_length(
                    chainstate.db(),
                    &parent_block_id,
                )
                .map_err(NakamotoNodeError::MiningFailure)?;
                info!("Miner: Extending read-count";
                      "burn_view_consensus_hash" => %burn_view_consensus_hash,
                      "parent_block_id" => %parent_block_id,
                      "num_blocks_so_far" => num_blocks_so_far,
                );

                // NOTE: this switches payload.cause to TenureChangeCause::Extend
                payload = payload.extend_with_cause(
                    burn_view_consensus_hash.clone(),
                    parent_block_id,
                    num_blocks_so_far,
                    TenureChangeCause::ExtendedReadCount,
                );
                let tenure_change_tx = self.generate_tenure_change_tx(current_miner_nonce, payload);
                (Some(tenure_change_tx), None)
            }
        };

        debug!(
            "make_tenure_start_info: reason = {:?}, burn_view = {:?}, tenure_change_tx = {:?}",
            &self.reason, &self.burn_block.consensus_hash, &tenure_change_tx
        );

        Ok(NakamotoTenureInfo {
            coinbase_tx,
            tenure_change_tx,
        })
    }

    /// Check if the tenure needs to change -- if so, return a BurnchainTipChanged error
    /// The tenure should change if there is a new burnchain tip with a valid sortition,
    /// or if the stacks chain state's burn view has advanced beyond our burn view.
    fn check_burn_tip_changed(&self, sortdb: &SortitionDB) -> Result<(), NakamotoNodeError> {
        let cur_burn_chain_tip = SortitionDB::get_canonical_burn_chain_tip(sortdb.conn())
            .expect("FATAL: failed to query sortition DB for canonical burn chain tip");

        if cur_burn_chain_tip.consensus_hash != self.burn_tip_at_start {
            info!("Miner: Cancel block assembly; burnchain tip has changed";
                "new_tip" => %cur_burn_chain_tip.consensus_hash,
                "local_tip" => %self.burn_tip_at_start);
            self.globals.counters.bump_missed_tenures();
            Err(NakamotoNodeError::BurnchainTipChanged)
        } else {
            Ok(())
        }
    }

    /// Set up the miner to try to issue a full tenure extend
    fn set_full_tenure_extend(&mut self) {
        self.tenure_change_time = Instant::now();
        self.reason = MinerReason::Extended {
            burn_view_consensus_hash: self.burn_block.consensus_hash.clone(),
        };
        self.mined_blocks = 0;
    }

    /// Set up the miner to try to issue a full tenure extend
    fn set_read_count_tenure_extend(&mut self) {
        self.tenure_change_time = Instant::now();
        self.reason = MinerReason::ReadCountExtend {
            burn_view_consensus_hash: self.burn_block.consensus_hash.clone(),
        };
        self.mined_blocks = 0;
    }
}

impl ParentStacksBlockInfo {
    // TODO: add tests from mutation testing results #4869
    #[cfg_attr(test, mutants::skip)]
    /// Determine where in the set of forks to attempt to mine the next anchored block.
    /// `parent_tenure_id` and `stacks_tip_header` identify the parent block on top of which to mine.
    /// `check_burn_block` identifies what we believe to be the burn chain's sortition history tip.
    /// This is used to mitigate (but not eliminate) a TOCTTOU issue with mining: the caller's
    /// conception of the sortition history tip may have become stale by the time they call this
    /// method, in which case, mining should *not* happen (since the block will be invalid).
    pub fn lookup(
        chain_state: &mut StacksChainState,
        burn_db: &mut SortitionDB,
        check_burn_block: &BlockSnapshot,
        miner_address: StacksAddress,
        parent_tenure_id: &StacksBlockId,
        stacks_tip_header: StacksHeaderInfo,
        reason: &MinerReason,
    ) -> Result<ParentStacksBlockInfo, NakamotoNodeError> {
        // the stacks block I'm mining off of's burn header hash and vtxindex:
        let parent_snapshot = SortitionDB::get_block_snapshot_consensus(
            burn_db.conn(),
            &stacks_tip_header.consensus_hash,
        )
        .expect("Failed to look up block's parent snapshot")
        .expect("Failed to look up block's parent snapshot");

        // don't mine off of an old burnchain block, unless we're late
        let burn_chain_tip = SortitionDB::get_canonical_burn_chain_tip(burn_db.conn())
            .expect("FATAL: failed to query sortition DB for canonical burn chain tip");

        // if we're mining a tenure that we were late to initialize, allow the burn tipped
        //  to be slightly stale
        if !reason.is_late_block()
            && burn_chain_tip.consensus_hash != check_burn_block.consensus_hash
        {
            info!(
                "New canonical burn chain tip detected. Will not try to mine.";
                "new_consensus_hash" => %burn_chain_tip.consensus_hash,
                "old_consensus_hash" => %check_burn_block.consensus_hash,
                "new_burn_height" => burn_chain_tip.block_height,
                "old_burn_height" => check_burn_block.block_height
            );
            return Err(NakamotoNodeError::BurnchainTipChanged);
        }

        let Ok(Some(parent_tenure_header)) =
            NakamotoChainState::get_block_header(chain_state.db(), parent_tenure_id)
        else {
            warn!("Failed loading parent tenure ID"; "parent_tenure_id" => %parent_tenure_id);
            return Err(NakamotoNodeError::ParentNotFound);
        };

        // check if we're mining a first tenure block (by checking if our parent block is in the tenure of parent_tenure_id)
        //  and if so, figure out how many blocks there were in the parent tenure
        let parent_tenure_info = if stacks_tip_header.consensus_hash
            == parent_tenure_header.consensus_hash
        {
            // in the same tenure
            let parent_tenure_blocks = if parent_tenure_header
                .anchored_header
                .as_stacks_nakamoto()
                .is_some()
            {
                let Ok(Some(last_parent_tenure_header)) =
                    NakamotoChainState::get_highest_block_header_in_tenure(
                        &mut chain_state.index_conn(),
                        &stacks_tip_header.index_block_hash(),
                        &parent_tenure_header.consensus_hash,
                    )
                else {
                    warn!("Failed loading last block of parent tenure"; "parent_tenure_id" => %parent_tenure_id);
                    return Err(NakamotoNodeError::ParentNotFound);
                };
                // the last known tenure block of our parent should be the stacks_tip. if not, error.
                if stacks_tip_header.index_block_hash()
                    != last_parent_tenure_header.index_block_hash()
                {
                    warn!("Last known tenure block of parent tenure should be the stacks tip";
                          "stacks_tip_header" => %stacks_tip_header.index_block_hash(),
                          "last_parent_tenure_header" => %last_parent_tenure_header.index_block_hash());
                    return Err(NakamotoNodeError::NewParentDiscovered);
                }
                1 + last_parent_tenure_header.stacks_block_height
                    - parent_tenure_header.stacks_block_height
            } else {
                1
            };
            let parent_tenure_consensus_hash = parent_tenure_header.consensus_hash.clone();
            Some(ParentTenureInfo {
                parent_tenure_blocks,
                parent_tenure_consensus_hash,
            })
        } else {
            None
        };

        debug!(
            "Looked up parent information";
            "parent_tenure_id" => %parent_tenure_id,
            "parent_tenure_consensus_hash" => %parent_tenure_header.consensus_hash,
            "parent_tenure_burn_hash" => %parent_tenure_header.burn_header_hash,
            "parent_tenure_burn_height" => parent_tenure_header.burn_header_height,
            "mining_consensus_hash" => %check_burn_block.consensus_hash,
            "mining_burn_hash" => %check_burn_block.burn_header_hash,
            "mining_burn_height" => check_burn_block.block_height,
            "stacks_tip_consensus_hash" => %parent_snapshot.consensus_hash,
            "stacks_tip_burn_hash" => %parent_snapshot.burn_header_hash,
            "stacks_tip_burn_height" => parent_snapshot.block_height,
            "parent_tenure_info" => ?parent_tenure_info,
            "stacks_tip_header.consensus_hash" => %stacks_tip_header.consensus_hash,
            "parent_tenure_header.consensus_hash" => %parent_tenure_header.consensus_hash,
            "reason" => %reason
        );

        let coinbase_nonce = {
            let principal = miner_address.into();
            let account = chain_state
                .with_read_only_clarity_tx(
                    &burn_db
                        .index_handle_at_block(chain_state, &stacks_tip_header.index_block_hash())
                        .map_err(|_| NakamotoNodeError::UnexpectedChainState)?,
                    &stacks_tip_header.index_block_hash(),
                    |conn| StacksChainState::get_account(conn, &principal),
                )
                .unwrap_or_else(|| {
                    panic!(
                        "BUG: stacks tip block {} no longer exists after we queried it",
                        &stacks_tip_header.index_block_hash()
                    )
                });
            account.nonce
        };

        Ok(ParentStacksBlockInfo {
            stacks_parent_header: stacks_tip_header,
            coinbase_nonce,
            parent_tenure: parent_tenure_info,
        })
    }
}

#[cfg(test)]
impl ReadCountCheck for () {
    fn get_read_count_extend_timestamp(&self) -> u64 {
        // always allow the read count extend
        0
    }
}

#[test]
fn should_read_count_extend_units() {
    let (sync_sender, _rcv_1) = std::sync::mpsc::sync_channel(1);
    let (relay_sender, _rcv_2) = std::sync::mpsc::sync_channel(1);
    let (_coord_rcv, coord_comms) =
        stacks::chainstate::coordinator::comm::CoordinatorCommunication::instantiate();
    let working_dir = tempdir().unwrap();

    let mut miner = BlockMinerThread {
        config: Config::default(),
        globals: Globals::new(
            coord_comms,
            Arc::new(std::sync::Mutex::new(
                stacks::chainstate::stacks::miner::MinerStatus::make_ready(10),
            )),
            relay_sender,
            crate::neon::Counters::new(),
            crate::syncctl::PoxSyncWatchdogComms::new(Arc::new(AtomicBool::new(true))),
            Arc::new(AtomicBool::new(true)),
            0,
            neon_node::LeaderKeyRegistrationState::Inactive,
        ),
        keychain: Keychain::default(vec![]),
        burnchain: Burnchain::regtest("/dev/null"),
        last_block_mined: Some((ConsensusHash([0; 20]), BlockHeaderHash([0; 32]))),
        mined_blocks: 1,
        tenure_cost: ExecutionCost::ZERO,
        tenure_budget: ExecutionCost::ZERO,
        registered_key: RegisteredKey {
            target_block_height: 0,
            block_height: 0,
            op_vtxindex: 0,
            vrf_public_key: stacks::util::vrf::VRFPublicKey::from_private(
                &stacks::util::vrf::VRFPrivateKey::new(),
            ),
            memo: vec![],
        },
        burn_election_block: BlockSnapshot::empty(),
        burn_block: BlockSnapshot::empty(),
        parent_tenure_id: StacksBlockId([0; 32]),
        event_dispatcher: EventDispatcher::new(working_dir.path().to_path_buf()),
        reason: MinerReason::Extended {
            burn_view_consensus_hash: ConsensusHash([0; 20]),
        },
        p2p_handle: NetworkHandle::new(sync_sender),
        signer_set_cache: None,
        tenure_change_time: Instant::now(),
        burn_tip_at_start: ConsensusHash([0; 20]),
        abort_flag: Arc::new(AtomicBool::new(false)),
        reset_mempool_caches: false,
        miner_db: MinerDB::open("/tmp/should_read_count_extend_units.db").unwrap(),
        temporarily_excluded_txids: HashSet::new(),
        permanently_excluded_txids: HashSet::new(),
    };
    miner.config.miner.read_count_extend_cost_threshold = 20;

    miner.tenure_cost = ExecutionCost {
        write_length: 1000,
        write_count: 1000,
        read_length: 1000,
        read_count: 199,
        runtime: 1000,
    };

    miner.tenure_budget = ExecutionCost {
        write_length: 1000,
        write_count: 1000,
        read_length: 1000,
        read_count: 1000,
        runtime: 1000,
    };

    assert_eq!(
        miner.should_read_count_extend(&()).unwrap(),
        false,
        "When read_count is below the configured threshold, we shouldn't try to extend"
    );

    miner.tenure_cost = ExecutionCost {
        write_length: 1000,
        write_count: 1000,
        read_length: 1000,
        read_count: 200,
        runtime: 1000,
    };

    miner.tenure_budget = ExecutionCost {
        write_length: 1000,
        write_count: 1000,
        read_length: 1000,
        read_count: 1000,
        runtime: 1000,
    };

    assert_eq!(
        miner.should_read_count_extend(&()).unwrap(),
        true,
        "When read_count is at the configured threshhold, we should try to extend"
    );
}

stacks-network / stacks-core / 25903914664-1

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