Hardhat plugin to compare contracts between upgrades to ensure storage compatibility.
This plugin generates a storage layout snapshot of the contracts in the project. It is precious for upgradable systems, as it helps you verify that the storage layout of the proxy contracts remains unchanged after the upgrade is done.
npm install --save-dev @solarity/hardhat-smart-compare
And add the following statement to your hardhat.config.js
:
require("@solarity/hardhat-smart-compare");
Or, if you are using TypeScript, add this to your hardhat.config.ts
:
import "@solarity/hardhat-smart-compare";
There are two tasks:
-
storage:save
task, which allows you to save the snapshot of the storage layout. -
storage:compare
task, which allows you to compare the current version of contracts with the previously saved snapshot.
To view the available options, run the command (help command):
npx hardhat help storage:save
npx hardhat help storage:compare
This plugin does not extend the environment.
To make a snapshot of the storage layout, run the following command:
npx hardhat storage:save
To compare the current version of contracts with the previously saved snapshot, run the following command:
npx hardhat storage:compare
The plugin completes the compile
task, retrieves artifacts from the Hardhat Runtime Environment (HRE), and performs the following actions depending on the task:
-
save
:
It will parse the build-info
file to get the compiler output and retrieve storage layout of contracts from the
outputSelection
field.
After that it will parse and save the storage layout for each contract with an inheritance "map" in a JSON file.
-
compare
:
Initially, it will execute the same steps as the save
task.
It will then thoroughly compare the existing snapshot and the newly generated version, scrutinizing each field and type.
Ultimately, if the --print-diff
flag is provided, it will display any differences that were identified.
The default configuration looks as follows. You may customize all fields in your hardhat config file.
module.exports = {
compare: {
snapshotPath: "./storage_snapshots",
snapshotFileName: "storage_snapshot.json",
},
};
-
snapshotPath
: Path to the directory where the storage layout snapshot is saved. -
snapshotFileName
: File name of the snapshot.
- Doesn't detect non-storage variables changes.
- Printed results are hard to comprehend.
-
Vyper
is currently not supported.