# Foundry Configuration Fix

**Date**: 2025-12-11
**Issue**: Warnings about unknown `etherscan` and `rpc_url` config in profiles

---

## ❌ Problem

Foundry was showing warnings:
```
Warning: Found unknown `etherscan` config for profile `mainnet` defined in foundry.toml.
Warning: Found unknown `rpc_url` config for profile `mainnet` defined in foundry.toml.
```

These warnings appeared for all network profiles (mainnet, cronos, bsc, polygon, gnosis, avalanche, base, arbitrum, optimism).

---

## ✅ Solution

Foundry profiles don't support `rpc_url` and `etherscan` as direct keys. These configurations should be referenced via command-line flags instead.

**Removed**: Profile sections with `rpc_url` and `etherscan` keys
**Kept**: `[rpc_endpoints]` and `[etherscan]` sections (these are correct)

---

## 📋 Correct Usage

### RPC Endpoints

Reference RPC endpoints by name from the `[rpc_endpoints]` section:

```bash
# Use mainnet RPC
forge script ... --rpc-url mainnet

# Use polygon RPC
forge script ... --rpc-url polygon
```

### Etherscan API Keys

Reference etherscan configs by name and pass the API key:

```bash
# For mainnet
forge verify-contract ... --etherscan-api-key $ETHERSCAN_API_KEY

# For polygon
forge verify-contract ... --etherscan-api-key $POLYGONSCAN_API_KEY
```

Or use the `--chain` flag with the etherscan config name:

```bash
forge verify-contract ... --chain polygon --etherscan-api-key $POLYGONSCAN_API_KEY
```

---

## 🔧 Configuration Structure

### Correct `foundry.toml` Structure

```toml
[rpc_endpoints]
mainnet = "${ETHEREUM_MAINNET_RPC}"
polygon = "${POLYGON_RPC_URL}"
# ... etc

[etherscan]
mainnet = { key = "${ETHERSCAN_API_KEY}" }
polygon = { key = "${POLYGONSCAN_API_KEY}", chain = "polygon" }
# ... etc

# Profiles should NOT contain rpc_url or etherscan keys
[profile.default]
# ... compiler settings
```

### Removed Profile Sections

The following profile sections were removed (they caused warnings):

```toml
# ❌ REMOVED - Not supported by Foundry
[profile.mainnet]
rpc_url = "mainnet"
etherscan = "mainnet"
chain_id = 1
```

---

## 📝 Chain IDs Reference

For reference when using `--chain-id` flag:

- **mainnet**: 1
- **cronos**: 25
- **bsc**: 56
- **polygon**: 137
- **gnosis**: 100
- **avalanche**: 43114
- **base**: 8453
- **arbitrum**: 42161
- **optimism**: 10

---

## ✅ Verification

After the fix, Foundry commands should run without warnings:

```bash
# Should show no warnings
forge script script/DeployMainnetTether.s.sol --rpc-url mainnet --dry-run

# Should show no warnings
forge verify-contract ... --etherscan-api-key $ETHERSCAN_API_KEY
```

---

## 📚 Additional Resources

- [Foundry Book - Configuration](https://book.getfoundry.sh/reference/config)
- [Foundry Book - Scripts](https://book.getfoundry.sh/reference/forge/forge-script)
- [Foundry Book - Verify](https://book.getfoundry.sh/reference/forge/forge-verify-contract)

---

**Last Updated**: 2025-12-11
**Status**: ✅ Fixed