Update Polygon cross-chain config to support Amoy testnet

It was unclear which testnet will replace the Mumbai testnet after the
deprecation of the underlying Goerli testnet. Now we know the new L2 testnet on
Polygon will be called `amoy` and will use the `80002` chain id. We can update
our config accordingly.
Read more:
maticnetwork/heimdall#1096
maticnetwork/bor#1072

cross-chain/polygon/.gitignore

@@ -10,6 +10,7 @@
 !/deployments/mainnet/
 !/deployments/polygon/
 !/deployments/mumbai/
+!/deployments/amoy/
 
 # OZ
 /.openzeppelin/unknown-*.json

cross-chain/polygon/README.adoc

@@ -27,7 +27,7 @@ Wormhole-specific tBTC representation into the canonical `PolygonTBTC` token.
 
 The deployment scripts are responsible for managing updates of the tBTC gateway
 addresses across various chains. These addresses are stored in the `external/`
-directory for a specific network, such as `mumbai/ArbitrumWormholeGateway.json.` 
+directory for a specific network, such as `amoy/ArbitrumWormholeGateway.json.` 
 It is important to note that these addresses should remain constant for the 
 mainnet network. However, there may be instances where a new version of a 
 cross-chain module is deployed to the testing network, which would require a 
@@ -42,7 +42,8 @@ yarn deploy --network <network>
 
 Supported networks:
 - `hardhat` - for local development
-- `mumbai` - testing network
+- `mumbai` - testing network (will become deprecated with the end of 2023)
+- `amoy` - testing network
 - `polygon` - mainnet
 
 Currently, this module does not deploy any contracts on L1. All the existing 

cross-chain/polygon/deploy_sidechain/02_verify_polygon_tbtc_token.ts

@@ -12,7 +12,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   // Contracts can be verified on Polygonscan in a similar way as we
   // do it on L1 Etherscan
   if (hre.network.tags.polygonscan) {
-    if (hre.network.name === "mumbai") {
+    if (hre.network.name === "mumbai" || hre.network.name === "amoy") {
       // Polygonscan might not include the recently added proxy transaction right
       // after deployment. We need to wait some time so that transaction is
       // visible on Polygonscan.

cross-chain/polygon/deploy_sidechain/04_verify_polygon_wormhole_gateway.ts

@@ -12,7 +12,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   // Contracts can be verified on Polygonscan in a similar way as we
   // do it on L1 Etherscan
   if (hre.network.tags.polygonscan) {
-    if (hre.network.name === "mumbai") {
+    if (hre.network.name === "mumbai" || hre.network.name === "amoy") {
       // Polygonscan might not include the recently added proxy transaction right
       // after deployment. We need to wait some time so that transaction is
       // visible on Polygonscan.

cross-chain/polygon/deploy_sidechain/12_update_self_in_wormhole_gateway_mapping.ts

@@ -8,7 +8,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
 
   // See https://book.wormhole.com/reference/contracts.html
   // This ID is valid for both Polygon Testnet (Mumbai) and Mainnet
-  // TODO: check ID for the new L2 Polygon testnet once it's annunced and supported by Wormhole
+  // TODO: check ID for the Amoy testnet once it's supported by Wormhole.
   const wormholeChainID = 5
 
   const polygonWormholeGateway = await deployments.get("PolygonWormholeGateway")

cross-chain/polygon/deploy_sidechain/32_manual_upgrade_polygon_wormhole_gateway.ts

@@ -57,7 +57,7 @@ const func: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
   // Contracts can be verified on L2 Polygonscan in a similar way as we do it on
   // L1 Etherscan
   if (hre.network.tags.polygonscan) {
-    if (hre.network.name === "mumbai") {
+    if (hre.network.name === "mumbai" || hre.network.name === "amoy") {
       // Polygonscan might not include the recently added proxy transaction right
       // after deployment. We need to wait some time so that transaction is
       // visible on Polygonscan.

cross-chain/polygon/hardhat.config.ts

@@ -74,8 +74,19 @@ const config: HardhatUserConfig = {
       //   parentchain: "goerli",
       // },
     },
-    // TODO: add new L2 Polygon testnet once it's annunced
-    // https://www.alchemy.com/overviews/migrate-to-sepolia#sepolia-testnets-on-alchemy
+    amoy: {
+      url: process.env.SIDECHAIN_API_URL || "",
+      chainId: 80002,
+      deploy: ["deploy_sidechain"],
+      accounts: process.env.SIDECHAIN_ACCOUNTS_PRIVATE_KEYS
+        ? process.env.SIDECHAIN_ACCOUNTS_PRIVATE_KEYS.split(",")
+        : undefined,
+      // Uncomment once Polygonscan supports Amoy testnet.
+      // tags: ["polygonscan"],
+      // companionNetworks: {
+      //   parentchain: "goerli",
+      // },
+    },
     polygon: {
       url: process.env.SIDECHAIN_API_URL || "",
       chainId: 137,
@@ -96,7 +107,7 @@ const config: HardhatUserConfig = {
       sepolia: ["./external/sepolia"],
       mainnet: ["./external/mainnet"],
       mumbai: ["./external/mumbai"],
-      // TODO: add new L2 Polygon testnet once it's annunced
+      amoy: ["./external/amoy"],
       polygon: ["./external/polygon"],
     },
   },
@@ -106,7 +117,7 @@ const config: HardhatUserConfig = {
     sepolia: "artifacts/parentchain",
     mainnet: "artifacts/parentchain",
     mumbai: "artifacts/sidechain",
-    // TODO: add new L2 Polygon testnet once it's annunced
+    amoy: "artifacts/sidechain",
     polygon: "artifacts/sidechain",
   },
 
@@ -116,9 +127,26 @@ const config: HardhatUserConfig = {
       sepolia: process.env.ETHERSCAN_API_KEY,
       mainnet: process.env.ETHERSCAN_API_KEY,
       polygonMumbai: process.env.POLYGONSCAN_API_KEY,
-      // TODO: add new L2 Polygon testnet once it's annunced
+      // TODO: uncomment once Amoy testnet is live and supported by Polygonscan.
+      // polygonAmoy: process.env.POLYGONSCAN_API_KEY,
       polygon: process.env.POLYGONSCAN_API_KEY,
     },
+    // TODO: Uncomment once Amoy testnet is live and supported by Polygonscan.
+    // The custom config will not be needed if `polygonAmoy` will be added to
+    // https://github.com/NomicFoundation/hardhat/blame/main/packages/hardhat-verify/src/internal/chain-config.ts.
+    // In that case we'll need to update `hardhat-verify` dependency.
+    // customChains: [
+    //   {
+    //     networkName: "polygonAmoy",
+    //     chainId: 80002,
+    //     urls: {
+    //       // Check below values in https://docs.polygonscan.com/getting-started/endpoint-urls
+    //       // once Polygonscan supports Amoy testnet.
+    //       apiURL: "https://api-testnet.polygonscan.com/api",
+    //       browserURL: "https://amoy.polygonscan.com/",
+    //     }
+    //   }
+    // ]
   },
 
   namedAccounts: {
@@ -127,7 +155,7 @@ const config: HardhatUserConfig = {
       goerli: 0,
       sepolia: 0,
       mumbai: 0,
-      // TODO: add new L2 Polygon testnet once it's annunced
+      amoy: 0,
       mainnet: "0x123694886DBf5Ac94DDA07135349534536D14cAf",
       polygon: "0x123694886DBf5Ac94DDA07135349534536D14cAf",
     },
@@ -136,7 +164,7 @@ const config: HardhatUserConfig = {
       goerli: 0,
       sepolia: 0,
       mumbai: 0,
-      // TODO: add new L2 Polygon testnet once it's annunced
+      amoy: 0,
       mainnet: "0x9f6e831c8f8939dc0c830c6e492e7cef4f9c2f5f",
       polygon: "0x9f6e831c8f8939dc0c830c6e492e7cef4f9c2f5f",
     },

cross-chain/polygon/package.json

@@ -31,6 +31,7 @@
     "lint:config:fix": "prettier --write '**/*.@(json|yaml)'",
     "prepack": "tsc -p tsconfig.export.json && hardhat export-artifacts export/artifacts",
     "export-artifacts:goerli": "yarn hardhat export-deployment-artifacts --network mumbai",
+    "export-artifacts:sepolia": "yarn hardhat export-deployment-artifacts --network amoy",
     "export-artifacts:mainnet": "yarn hardhat export-deployment-artifacts --network polygon",
     "prepublishOnly": "npm run export-artifacts:$npm_config_network",
     "test": "hardhat test"