Zokyo Gas Savings
  • โ›ฝZokyo Gas Savings
  • ๐Ÿ“šTutorials
    • โœ”๏ธGas Saving Technique 1: Unchecked Arithmetic
    • โ›“๏ธGas Saving Technique 2: Immutable Variable
    • โœจGas Saving Technique 3: Double star ** inefficiency
    • ๐Ÿ’ฐGas Saving Technique 4: Cache Array Length
    • โฌ…๏ธGas Saving Technique 5: ++i costs less gas compared to i++
    • โš–๏ธGas Saving Technique 6: NOT operator ! cheaper than boolean FALSE
    • ๐ŸชกGas Saving Technique 7: Using Short Reason Strings
    • ๐ŸชตGas Saving Technique 8: Use Custom Errors instead of Revert Strings to save Gas
    • โœ’๏ธGas Saving Technique 9: Use Custom Errors instead of Revert Strings to save Gas
    • ๐Ÿ‘พGas Saving Technique 10: Calldata cheaper than memory
    • โ›”Gas Saving Technique 11: > 0 is less efficient than != 0 for unsigned integers
    • โž—Gas Saving Technique 12: SafeMath no longer needed
    • ๐Ÿ˜ฎGas Saving Technique 13: variables default to 0
    • ๐ŸงฑGas Saving Technique 14: struct layout/ variable packing
    • ๐Ÿ“žGas Saving Technique 15: Cache External Call
    • โœ๏ธGas Saving Technique 16: Early Validation before external call
    • ๐Ÿ˜ŽGas Saving Technique 17: Donโ€™t cache value that is used once
    • ๐Ÿ˜งGas Saving Technique 18: Redundant code
    • โœ…Gas Saving Technique 19: Early Validation before external call
    • โ›๏ธGas Saving Technique 20: Storage vs Memory read optimizations
    • โœ’๏ธGas Saving Technique 21: Unneeded If statements
    • ๐ŸŒ—Gas Saving Technique 22: >= is cheaper than >
    • ๐ŸŽ’Gas Saving Technique 23: Public to private constants
    • โน๏ธGas Saving Technique 24: Make unchanged variables constant/immutable
    • โฑ๏ธGas Saving Techniques 25: Redundant Access Control Checks
    • โžก๏ธGas Saving Technique 26: Shift Right instead of Dividing by 2
    • ๐ŸชƒGas Saving Tutorial 27: Efficient Boolean Comparison
    • ๐ŸคGas Saving Technique 28: && operator uses more gas
    • ๐Ÿ‘“Gas Saving Technique 29: x = x + y is cheaper than x += y
    • ๐Ÿ‘‚Gas Saving Technique 30: Using 1 and 2 rather than 0 and 1 saves gas
    • โšฝGas Saving Technique 31: Optimize Storage by Avoiding Booleans
    • ๐Ÿ”™Gas Saving Technique 32: Optimal Use of Named Return Variables in Solidity
    • ๐Ÿ›ข๏ธGas Saving Technique 33: Making Functions Payable for Optimized Gas Costs
    • โœ๏ธGas Saving Technique 34: Optimizing Storage References in Smart Contracts
    • โ›ฐ๏ธGas Saving Technique 35: Usage of uints/ints smaller than 32 bytes (256 bits) incurs overhead
    • ๐ŸŒช๏ธGas Saving Technique 36: Inlining Single Use Internal Functions for Savings
    • โ˜„๏ธGas Saving Technique 37: Switching from Public to External Functions for Savings
    • ๐ŸŽ†Gas Saving Technique 38: Upgrading Solidity Compiler to Improve Gas Efficiency and Security
    • ๐Ÿ•ถ๏ธGas Saving Technique 39: Avoiding Duplicated Code for Gas Savings
    • ๐Ÿ˜„Gas Saving Technique 40: Removal of Unused Internal Functions for Gas Savings
    • ๐Ÿ–‹๏ธGas Saving Tutorial 41: In-lining Single Use Modifiers For Gas Saving
    • โ›๏ธGas Saving Technique 42: `require` vs`assert`
Powered by GitBook
On this page
  1. Tutorials

Gas Saving Technique 23: Public to private constants

PreviousGas Saving Technique 22: >= is cheaper than >NextGas Saving Technique 24: Make unchanged variables constant/immutable

Last updated 1 year ago

Introduction:

Within a smart contract, the visibility of constants can have a subtle but notable impact on gas usage. This tutorial will guide you through the benefits of adjusting the visibility of constants from public to private or internal as a means of saving gas.

Understanding the Impact:

In Solidity, public variables have an automatically generated getter function, which, although useful, incurs extra gas cost during contract deployment. If a constant doesn't need to be accessed outside of the contract or derived contracts, changing its visibility can result in gas savings.

Vulnerability Details:

Deploying a contract with numerous public constants can unnecessarily increase its deployment gas cost due to the added getter functions. Moreover, every time these constants are accessed, additional gas is used.

Example:

Using public constant:

solidityCopy codepragma solidity ^0.8.0;

contract GasSaver {
    // Public constant with generated getter function
    uint256 public constant SOME_VALUE = 12345;
}

Optimized Version Using internal constant:

solidityCopy codepragma solidity ^0.8.0;

contract GasSaver {
    // Internal constant without generated getter function
    uint256 internal constant SOME_VALUE = 12345;
}

Mitigation Steps:

  1. Review Constants: Examine your contract for public constants.

  2. Adjust Visibility: If a constant doesnโ€™t need to be accessed outside of the contract or by derived contracts, consider changing its visibility to internal. If it does not need to be accessed by derived contracts either, consider making it private.

  3. Test the Contract: Ensure your contract still behaves as expected after making visibility adjustments.

Benefits:

  • Gas Efficiency: Reducing visibility can save gas on contract deployment and when accessing constants.

  • Encapsulation: It promotes better encapsulation and contract abstraction, enhancing contract security and readability.

Consideration:

  • Accessibility: Ensure that no external component relies on the visibility of these constants before making changes.

Conclusion:

While the gas savings might be minor per operation, in contracts with high transaction volume or many constants, these savings accumulate. Additionally, this practice enhances the encapsulation within your contract, promoting a cleaner and more secure codebase. Always test thoroughly after making optimizations to ensure the contract's functionality remains intact.

๐Ÿ“š
๐ŸŽ’
Book an audit with Zokyo