Upgradability Proxy ADMIN_SLOT assembly sstore does not update

Question

I'm currently playing around with Proxy Upgradability, and noticed the use of assembly in terms of the new upgraded contract and the slot assigned. Real implementation can be seen here.

I have broken this implementation down to understand what is happening:

pragma solidity ^0.5.0;

contract Base {

bytes32 internal constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;


function _setImplementation(address newImplementation) public {
   bytes32 slot = IMPLEMENTATION_SLOT;

   assembly {
     sstore(slot, newImplementation)
   }
}

function _implementation() public view returns (address impl) {
   bytes32 slot = IMPLEMENTATION_SLOT;
   assembly {
     impl := sload(slot)
   }
}

function getSlot() public view returns(bytes32) {
    return IMPLEMENTATION_SLOT;
}
}

Then created tests to see the results, and see what is modified etc...

const Base = artifacts.require("Base")

contract('Base', function(account) {

beforeEach(async function () {
    this.base = await Base.new();
})
describe('...', function () {
    describe('...', function () {
        it('check slot', async function () {
            console.log(await this.base.getSlot());
        })

        it('check slot', async function () {
            console.log(await this.base._implementation());
        })

        it('change slot', async function () {
            console.log(account[0]);
            await this.base._setImplementation(account[0]);
        })

        it('check slot', async function () {
            console.log(await this.base.getSlot());
        })

        it('check slot', async function () {
            console.log(await this.base._implementation());
        })

    })
})
})

Which gives the result:

0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3
    ✓ check slot
0x0000000000000000000000000000000000000000
    ✓ check slot
0x627306090abaB3A6e1400e9345bC60c78a8BEf57
    ✓ change slot (69ms)
0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3
    ✓ check slot
0x0000000000000000000000000000000000000000
    ✓ check slot

Why does the slot variable not change, and if that is not meant to change, why does ADMIN_SLOT not change either?

Answer 1

You are deploying a new instance before every test so any changes will be ignored in following tests

beforeEach(async function () {
    this.base = await Base.new();
})