Repository: bitcoin/bitcoin
File: src/rpc/blockchain.cpp (C++)

Code before:
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Negative block height.");
    }

    // Height value more than a billion is too high to be a block height, and
    // too low to be a block time (corresponds to timestamp from Sep 2001).
    if (heightParam > 1000000000) {
        // Add a 2 hour buffer to include blocks which might have had old timestamps
        const CBlockIndex* pindex = active_chain.FindEarliestAtLeast(heightParam - TIMESTAMP_WINDOW, 0);
        if (!pindex) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Could not find block with at least the specified timestamp.");
        }
        heightParam = pindex->nHeight;
    }

    unsigned int height = (unsigned int) heightParam;
    unsigned int chainHeight = (unsigned int) active_chain.Height();
    if (chainHeight < chainman.GetParams().PruneAfterHeight()) {
        throw JSONRPCError(RPC_MISC_ERROR, "Blockchain is too short for pruning.");
    } else if (height > chainHeight) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Blockchain is shorter than the attempted prune height.");
    } else if (height > chainHeight - MIN_BLOCKS_TO_KEEP) {
        LogPrint(BCLog::RPC, "Attempt to prune blocks close to the tip.  Retaining the minimum number of blocks.\n");
        height = chainHeight - MIN_BLOCKS_TO_KEEP;
    }

    PruneBlockFilesManual(active_chainstate, height);
    const CBlockIndex& block{*CHECK_NONFATAL(active_chain.Tip())};
    return block.nStatus & BLOCK_HAVE_DATA ? active_chainstate.m_blockman.GetFirstStoredBlock(block)->nHeight - 1 : block.nHeight;
},
    };
}

CoinStatsHashType ParseHashType(const std::string& hash_type_input)
{
    if (hash_type_input == "hash_serialized_3") {
        return CoinStatsHashType::HASH_SERIALIZED;
    } else if (hash_type_input == "muhash") {
        return CoinStatsHashType::MUHASH;
    } else if (hash_type_input == "none") {
        return CoinStatsHashType::NONE;
    } else {
        throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("'%s' is not a valid hash_type", hash_type_input));
    }
}

/**
 * Calculate statistics about the unspent transaction output set
 *
 * @param[in] index_requested Signals if the coinstatsindex should be used (when available).
 */
static std::optional<kernel::CCoinsStats> GetUTXOStats(CCoinsView* view, node::BlockManager& blockman,

Review comment (bug):
```suggestion
    return block.nStatus & has_undo ? active_chainstate.m_blockman.GetFirstStoredBlock(block, /*lower_block=*/nullptr, /*status_mask=*/has_undo)->nHeight - 1 : block.nHeight;
```

Code after:
                {
                    {"height", RPCArg::Type::NUM, RPCArg::Optional::NO, "The block height to prune up to. May be set to a discrete height, or to a " + UNIX_EPOCH_TIME + "\n"
            "                  to prune blocks whose block time is at least 2 hours older than the provided timestamp."},
                },
                RPCResult{
                    RPCResult::Type::NUM, "", "Height of the last block pruned"},
                RPCExamples{
                    HelpExampleCli("pruneblockchain", "1000")
            + HelpExampleRpc("pruneblockchain", "1000")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    ChainstateManager& chainman = EnsureAnyChainman(request.context);
    if (!chainman.m_blockman.IsPruneMode()) {
        throw JSONRPCError(RPC_MISC_ERROR, "Cannot prune blocks because node is not in prune mode.");
    }

    LOCK(cs_main);
    Chainstate& active_chainstate = chainman.ActiveChainstate();
    CChain& active_chain = active_chainstate.m_chain;

    int heightParam = request.params[0].getInt<int>();
    if (heightParam < 0) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Negative block height.");
    }

    // Height value more than a billion is too high to be a block height, and
    // too low to be a block time (corresponds to timestamp from Sep 2001).
    if (heightParam > 1000000000) {
        // Add a 2 hour buffer to include blocks which might have had old timestamps
        const CBlockIndex* pindex = active_chain.FindEarliestAtLeast(heightParam - TIMESTAMP_WINDOW, 0);
        if (!pindex) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Could not find block with at least the specified timestamp.");
        }
        heightParam = pindex->nHeight;
    }

    unsigned int height = (unsigned int) heightParam;
    unsigned int chainHeight = (unsigned int) active_chain.Height();
    if (chainHeight < chainman.GetParams().PruneAfterHeight()) {
        throw JSONRPCError(RPC_MISC_ERROR, "Blockchain is too short for pruning.");
    } else if (height > chainHeight) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Blockchain is shorter than the attempted prune height.");
    } else if (height > chainHeight - MIN_BLOCKS_TO_KEEP) {
        LogPrint(BCLog::RPC, "Attempt to prune blocks close to the tip.  Retaining the minimum number of blocks.\n");
        height = chainHeight - MIN_BLOCKS_TO_KEEP;
    }

    PruneBlockFilesManual(active_chainstate, height);
    return GetPruneHeight(chainman.m_blockman, active_chain).value_or(-1);
},