Etherscan V2 workaround (#2679)

* configure workaround for Etherscan V2 api

* fix typo

* fix endpoint configuration error

* add verification examples to readme where deployed contracts have constructor parameters

Author: sparrowDom

contracts/README.md

@@ -419,14 +419,51 @@ Validator public key: 90db8ae56a9e741775ca37dd960606541306974d4a998ef6a6227c85a9
 
 ## Contract Verification
 
-The Hardhat plug-in [@nomiclabs/hardhat-etherscan](https://www.npmjs.com/package/@nomiclabs/hardhat-etherscan) is used to verify contracts on Etherscan.
+The Hardhat plug-in [@nomiclabs/hardhat-verify](https://www.npmjs.com/package/@nomiclabs/hardhat-etherscan) is used to verify contracts on Etherscan. Etherscan has migrated to V2 api where all the chains use the same endpoint. Hardhat verify should be run with `--contract` parameter otherwise there is a significant slowdown while hardhat is gathering contract information. 
 
 There's an example
 
 ```
 npx hardhat --network mainnet verify --contract contracts/vault/VaultAdmin.sol:VaultAdmin 0x31a91336414d3B955E494E7d485a6B06b55FC8fB
 ```
 
+Example with constructor parameters passed as command params
+```
+yarn hardhat verify --network mainnet 0x0FC66355B681503eFeE7741BD848080d809FD6db --contract contracts/poolBooster/PoolBoosterFactoryMerkl.sol:PoolBoosterFactoryMerkl 0x856c4Efb76C1D1AE02e20CEB03A2A6a08b0b8dC3 0x4FF1b9D9ba8558F5EAfCec096318eA0d8b541971 0xAA8af8Db4B6a827B51786334d26349eb03569731 0x8BB4C975Ff3c250e0ceEA271728547f3802B36Fd
+```
+
+Example with constructor parameters saved to file and file path passed to the command
+```
+echo "module.exports = [{
+  platformAddress: \"0x0000000000000000000000000000000000000001\",
+  vaultAddress: \"0xe75d77b1865ae93c7eaa3040b038d7aa7bc02f70\",
+}]" > flux-args.js
+npx hardhat --network mainnet verify --contract contracts/strategies/FluxStrategy.sol:FluxStrategy --constructor-args flux-args.js 0x57d49c28Cf9A0f65B1279a97eD01C3e49a5A173f
+```
+
+
+
+`hardhat-deploy` package offers a secondary way to verify contracts, where contructor parameters don't need to be passed into the verification call. Since Etherscan has migrated to V2 api this approach is no longer working. `etherscan-verify` call uses `hardhat verify` under the hood.
+```
+npx hardhat etherscan-verify --network mainnet --api-url https://api.etherscan.io
+```
+
+#### Addressing verification slowdowns
+
+Profiling the `hardhat-verify` prooved that when the `hardhat verify` is ran without --contract parameter 
+it can take up to 4-5 minutes to gather the necessary contract information. 
+Use `--contract` e.g. `--contract contracts/vault/VaultAdmin.sol:VaultAdmin` to mitigate the issue.
+
+#### Migration to full support of Etherscan V2 api
+
+Migrating to Etherscan V2 has been attempted with no success.
+Resources:
+ - migration guid by Etherscan: https://docs.etherscan.io/v2-migration
+ - guide for Hardhat setup: https://docs.etherscan.io/contract-verification/verify-with-hardhat. (note upgrading @nomicfoundation/hardhat-verify to 2.0.14 didn't resolve the issue last time) 
+ - openzeppelin-upgrades claims to have solved the issue in 3.9.1 version of the package: https://github.com/OpenZeppelin/openzeppelin-upgrades/issues/1165 Not only does this not solve the verification issue, it is also a breaking change for our repo.
+
+Good luck when attempting to solve this. 
+
 ### Deployed contract code verification
 
 To verify the deployed contract against the locally compiled contracts sol2uml from Nick Addison is convenient:

contracts/hardhat.config.js

@@ -415,35 +415,43 @@ module.exports = {
   etherscan: {
     apiKey: {
       mainnet: process.env.ETHERSCAN_API_KEY,
-      arbitrumOne: process.env.ARBISCAN_API_KEY,
+      arbitrumOne: process.env.ETHERSCAN_API_KEY,
       holesky: process.env.ETHERSCAN_API_KEY,
-      base: process.env.BASESCAN_API_KEY,
-      sonic: process.env.SONICSCAN_API_KEY,
-      hoodi: process.env.HOODISCAN_API_KEY,
+      base: process.env.ETHERSCAN_API_KEY,
+      sonic: process.env.ETHERSCAN_API_KEY,
+      hoodi: process.env.ETHERSCAN_API_KEY,
       plume: "empty", // this works for: npx hardhat verify...
     },
     customChains: [
+      {
+        network: "mainnet",
+        chainId: 1,
+        urls: {
+          apiURL: "https://api.etherscan.io/v2/api?chainId=1",
+          browserURL: "https://etherscan.io",
+        },
+      },
       {
         network: "holesky",
         chainId: 17000,
         urls: {
-          apiURL: "https://api-holesky.etherscan.io/api",
+          apiURL: "https://api.etherscan.io/v2/api?chainId=17000",
           browserURL: "https://holesky.etherscan.io",
         },
       },
       {
         network: "base",
         chainId: 8453,
         urls: {
-          apiURL: "https://api.basescan.org/api",
+          apiURL: "https://api.etherscan.io/v2/api?chainId=8453",
           browserURL: "https://basescan.org",
         },
       },
       {
         network: "sonic",
         chainId: 146,
         urls: {
-          apiURL: "https://api.sonicscan.org/api",
+          apiURL: "https://api.etherscan.io/v2/api?chainId=146",
           browserURL: "https://sonicscan.org",
         },
       },
@@ -459,7 +467,7 @@ module.exports = {
         network: "hoodi",
         chainId: 560048,
         urls: {
-          apiURL: "https://hoodi.etherscan.io/api",
+          apiURL: "https://api.etherscan.io/v2/api?chainId=560048",
           browserURL: "https://hoodi.etherscan.io",
         },
       },