Web3bridge Students (Cohort XI) Share What They’ve Learned: Upgradeable Smart Contract

this video is proudly brought to you by WD with lcks our official sponsors for cohort 11 I know you must have heard that smart contracts are immutable and um they cannot be changed but why are we talking about upgradable smart contracts now what if there was a bug in your smart contract how do you remediate that or say you want to add additional functionalities to the smart contract how do you mod how do you remediate that that is your upgradable smart contract comes into [Music] play firstly what is the need for UPG smart contract so as you know with smart contracts are fixed when you deploy a particular smart contract as we know it you cannot make changes to the code and if you make changes to the code you have to redeploy and redeploying it means you are redeploying the smart contract code to a different um address on the blockchain but now this is what upgradable smart contract does it gives you the ability to write a smart contract and then keep on upgrading the contract code using that same address now how does this work right for up smart contract it works using the principle of proxy and implementation so there's usually a proxy which we will call the mother contract and then the implementations who will call the children contract so in the mother contract we always have storage so storage is not in the children contract or like I called it the implementation contract it is just in the mother contract but then this implementation contract just import the storage in the mod contract and then make changes to that storage using what we call delegate call so now what is delegate call in very very brief form delegate call is simply making um a call to another contract to make changes to your own storage so like the the concept I use of mother and child when the mother makes a delegate call to the child she's simply saying the child should run some particular function that changes her own um storage or her own States upgradable smart contract make use of the proxy and implementation um the proxy implementation design and then under the hood it makes use of delegate call to achieve this so one thing to not is that when we talk about upgradable smart contract you are not modifying the state or the address of the contract you're just adding functionality or trying to remediate a BG so the contract that is deployed the address is maintained the balances all the transactions that that that have been performed on contracts are still maintained just adding functionalities to it now this upgradable smart contracts makes use of something known as the proxy pattern just like my colleague has said which consist of the proy um contract and then the execution contract or some also known as the facets such that the proy contract holds the address to the um execution contract and uses the logic in the execution contract to update it own State now there are types of um upgradable smart contracts we have the um transparent proxy which is also known as the simple proxy which uses delegate call to call the facet or the execution contracts and that's why that is preferred it has its own drawback and also there is another type known as the universal frogy umy which is another type of upgradable smart contract one thing to note is that um in this case the proxy is the one calling the user calls the proxy which cause the facet or the execution logic which holds the logic that is to be used to either make upgrades make changes to the contract or even remediate a b companies like aoi companies like composable Finance use Diamond smart contract to um enhance the applications right they have this they use they make use of di smart contract to make their contracts upgradable right a modular to save gas cost to always update their contracts to hard or to replace um or to remove faets right that is implementation contract [Music]