Function TestBlockValidity

src/validation.cpp:4480–4551

BlockValidationState TestBlockValidity(
    Chainstate& chainstate,
    const CBlock& block,
    const bool check_pow,
    const bool check_merkle_root)
{
    // Lock must be held throughout this function for two reasons:
    // 1. We don't want the tip to change during several of the validation steps
    // 2. To prevent a CheckBlock() race condition for fChecked, see ProcessNewBlock()
    AssertLockHeld(chainstate.m_chainman.GetMutex());

    BlockValidationState state;
    CBlockIndex* tip{Assert(chainstate.m_chain.Tip())};

    if (block.hashPrevBlock != *Assert(tip->phashBlock)) {
        state.Invalid({}, "inconclusive-not-best-prevblk");
        return state;
    }

    // For signets CheckBlock() verifies the challenge iff fCheckPow is set.
    if (!CheckBlock(block, state, chainstate.m_chainman.GetConsensus(), /*fCheckPow=*/check_pow, /*fCheckMerkleRoot=*/check_merkle_root)) {
        // This should never happen, but belt-and-suspenders don't approve the
        // block if it does.
        if (state.IsValid()) NONFATAL_UNREACHABLE();
        return state;
    }

    /**
     * At this point ProcessNewBlock would call AcceptBlock(), but we
     * don't want to store the block or its header. Run individual checks
     * instead:
     * - skip AcceptBlockHeader() because:
     *   - we don't want to update the block index
     *   - we do not care about duplicates
     *   - we already ran CheckBlockHeader() via CheckBlock()
     *   - we already checked for prev-blk-not-found
     *   - we know the tip is valid, so no need to check bad-prevblk
     * - we already ran CheckBlock()
     * - do run ContextualCheckBlockHeader()
     * - do run ContextualCheckBlock()
     */

    if (!ContextualCheckBlockHeader(block, state, chainstate.m_chainman, tip)) {
        if (state.IsValid()) NONFATAL_UNREACHABLE();
        return state;
    }

    if (!ContextualCheckBlock(block, state, chainstate.m_chainman, tip)) {
        if (state.IsValid()) NONFATAL_UNREACHABLE();
        return state;
    }

    // We don't want ConnectBlock to update the actual chainstate, so create
    // a cache on top of it, along with a dummy block index.
    CBlockIndex index_dummy{block};
    uint256 block_hash(block.GetHash());
    index_dummy.pprev = tip;
    index_dummy.nHeight = tip->nHeight + 1;