⟁ Storage Delta

Storage Delta is a tool for auditing storage layout changes during contract upgrades.

Install

Powered by Foundry.

forge install 0xPolygon/storage-delta

Run

Storage Delta analyzes the entire contract suite against any previous version.

bash lib/storage-delta/run.sh <COMMIT_OR_TAG>

./storage_delta will be generated if there are findings. Open OLD and NEW files side by side for the best experience.

Detectors

	Description
🌱	New
🏴	Problematic
🏳️	Moved
🏁	Moved & problematic
🪦	Removed
	Dirty bytes

New

When a variable with a unique name and type is added.

    uint256 a

    uint256 a
🌱  bool b

Problematic

When a new variable is added, but conflicts with the existing storage.

    uint256 a

🏴  bool b

Moved

When an existing variable is moved.

    uint256 a
    ...

    ...
🏳️  uint256 a

Moved & problematic

When an existing variable is moved and conflicts with the existing storage.

    uint256 a
    bool b

🏁  bool b
🏁  uint256 a

Removed

When a variable no longer exists.

    uint256 a
    bool b

    uint256 a
🪦

Dirty bytes

When the storage is not clean.

    uint256 a

🏴  uint128 a
    16 dirty bytes

Configuration

Option	Values	Description
--omit	new	Do not generate a report with only those findings.

Requirements

Files should be named after the contract they hold. Example → Example.sol

The script utilizes Node.js to run. We recommend the node version defined in the .nvmrc file.

License

​ Licensed under either of ​

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) ​

at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

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