Solidity Tech Talk - Bad Code

BadStalenessChecker.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";
import "https://github.com/smartcontractkit/chainlink/blob/develop/evm-contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

contract BadStalenessChecker is Ownable {
    
    // Details about a price feed.
    struct PriceFeedDetails {
        AggregatorV3Interface aggregator;
        uint stalenessThreshold;
    }

    // The name of this contract
    string public name;
    // The target price feed
    PriceFeedDetails public priceFeed;
    // The proposed price feed
    PriceFeedDetails public proposedPriceFeed;
    
    // Events
    event PriceFeedProposed(AggregatorV3Interface indexed proposed);
    event PriceFeedConfirmed(AggregatorV3Interface indexed previous, AggregatorV3Interface indexed confirmed);
    
    // Constructor
    constructor(
        string memory contractName
    ) Ownable() {
        name = contractName;
    }
    
    // Propose a new price feed to check for staleness
    function proposeNewPriceFeed(
        AggregatorV3Interface newAggregator,
        uint newThreshold
    )
        external
        onlyOwner()
    {
        priceFeed = PriceFeedDetails({
            aggregator: newAggregator,
            stalenessThreshold: newThreshold
        });
        emit PriceFeedProposed(newAggregator);
    }
    
    // Confirm a proposed price feed
    function confirmPriceFeed(
        AggregatorV3Interface newAggregator
    )
        external
        onlyOwner()
    {
        emit PriceFeedConfirmed(priceFeed.aggregator, newAggregator);
        priceFeed = proposedPriceFeed;
    }
    
    // Return true if the price feed is stale
    function checkIfStale()
        external
        view
        returns (
            bool
        )
    {
        (,,,uint timeStamp,) = priceFeed.aggregator.latestRoundData();
        return (block.timestamp - timeStamp) > priceFeed.stalenessThreshold;
    }
}