Upgrading Proxy contracts

Hi i have used your proxy pattern for upgradeable contract it worked fine but i have one problem. i have two variable which had some values but after deployed contarct with proxy those values getting 0. what i sholud to do for those values.

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Hi @love_chawda,

Existing state variables should maintain their state, assuming you didn’t change the order nor type of the declared state variables.

Were there any issues reported during upgrading?

It would be helpful if you could share your contract (original version and upgraded version).

uint256 public feePercent = 150;
address public feeAddress = 0x2DAB20a2b069Ad67656F4a457E898F61516c8982;

there is initial values and when i use this with proxy it is getting 0. but if i have set with setter method than it give me the setted values. but i want first time initialize with proxy call.

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Hi @love_chawda,

If you haven’t already, you may want to look at Learn guide: Upgrading Smart Contracts

I assume that your contract looks a little like the following.
When we create the contract, we need to initialize it. We can then read those values.


pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

contract MyContract is Initializable {
  uint256 public myPercent;
  address public myAddress;

  function initialize(uint256 initialMyPercent, address initialMyAddress) initializer public {
    myPercent = initialMyPercent;
    myAddress = initialMyAddress;

Deploy contract

$ oz create
✓ Compiled contracts with solc 0.5.16 (commit.9c3226ce)
? Pick a contract to instantiate MyContract
? Pick a network development
✓ Added contract MyContract
✓ Contract MyContract deployed
All contracts have been deployed
? Call a function to initialize the instance after creating it? Yes
? Select which function * initialize(initialMyPercent: uint256, initialMyAddress: address)
? initialMyPercent (uint256): 150
? initialMyAddress (address): 0xFFcf8FDEE72ac11b5c542428B35EEF5769C409f0
✓ Setting everything up to create contract instances
✓ Instance created at 0xCfEB869F69431e42cdB54A4F4f105C19C080A601

Call contract

$ oz call
? Pick a network development
? Pick an instance MyContract at 0xCfEB869F69431e42cdB54A4F4f105C19C080A601
? Select which function myPercent()
✓ Method 'myPercent()' returned: 150
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okay thankyou i will try with this

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Hi @love_chawda,

How did you get on?

i am working on it.but i have one more question. would i call initialize method manually?

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Hi @love_chawda,

Apologies, I only saw this question.
You can call initialize as part of oz create.

I’m sure @love_chawda has moved past this already but for the record I believe the problem was that in the implementation contract the state variables were initialized as part of their declaration as shown below, and not as part of the initializer function.

The actual values asigned to these variables should be assigned in the initializer function, otherwise it won’t work with proxies. The CLI detects this and emits an error.

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