feat: add getErc20Address method to IFunToken (#2260)

* feat: add getErc20Address method to IFunToken and implement its logic in precompile

* feat: changelog

* fix: remove debug print

* feat: enhance getErc20Address method to validate token factory denominations

* fix: lint and fixes

Author: matthiasmatt

CHANGELOG.md

@@ -51,6 +51,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [#2251](https://github.com/NibiruChain/nibiru/pull/2251) - feat(evm): add ERC20 contract with metadata updates
 - [#2249](https://github.com/NibiruChain/nibiru/pull/2249) - fix(evm): resetting gas meter for afterOp in bank extension
 - [#2257](https://github.com/NibiruChain/nibiru/pull/2257) - fix: simulation tests by register interfaces for vesting and use correct app keys field
+- [#2260](https://github.com/NibiruChain/nibiru/pull/2260) - feat(evm): add getErc20Address method to IFunToken
 - [#2259](https://github.com/NibiruChain/nibiru/pull/2259) - feat: add depinject wiring for all sdk modules
 - [#2261](https://github.com/NibiruChain/nibiru/pull/2261) - feat: gen pulsar api and app wiring for sudo
 - [#2262](https://github.com/NibiruChain/nibiru/pull/2262) - feat: app wiring for oracle
@@ -82,7 +83,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [#2206](https://github.com/NibiruChain/nibiru/pull/2206) - ci(chaosnet): fix docker image build
 - [#2207](https://github.com/NibiruChain/nibiru/pull/2207) - chore(ci): add cache for chaosnet builds
 - [#2209](https://github.com/NibiruChain/nibiru/pull/2209) - refator(ci):
-Simplify GitHub actions based on conditional paths, removing the need for files like ".github/workflows/skip-unit-tests.yml".
+  Simplify GitHub actions based on conditional paths, removing the need for files like ".github/workflows/skip-unit-tests.yml".
 - [#2211](https://github.com/NibiruChain/nibiru/pull/2211) - ci(chaosnet): avoid building on cache injected directories
 - [#2212](https://github.com/NibiruChain/nibiru/pull/2212) - fix(evm): proper eth tx logs emission for funtoken operations
 - [#2213](https://github.com/NibiruChain/nibiru/pull/2213) - chore(build): include lib versions on cache
@@ -123,14 +124,14 @@ Simplify GitHub actions based on conditional paths, removing the need for files
 - [#2145](https://github.com/NibiruChain/nibiru/pull/2145) - chore(token-registry): add xNIBI Astrovault LST to registry
 - [#2147](https://github.com/NibiruChain/nibiru/pull/2147) - fix(simapp): manually add x/vesting Cosmos-SDK module types to the codec in simulation tests since they are expected by default
 - [#2149](https://github.com/NibiruChain/nibiru/pull/2149) - feat(evm-oracle):
-add Solidity contract that we can use to expose the Nibiru Oracle in the
-ChainLink interface. Publish all precompiled contracts and ABIs on npm under
-the `@nibiruchain/solidity` package.
+  add Solidity contract that we can use to expose the Nibiru Oracle in the
+  ChainLink interface. Publish all precompiled contracts and ABIs on npm under
+  the `@nibiruchain/solidity` package.
 - [#2151](https://github.com/NibiruChain/nibiru/pull/2151) - feat(evm): randao support for evm
 - [#2152](https://github.com/NibiruChain/nibiru/pull/2152) - fix(precompile): consume gas for precompile calls regardless of error
 - [#2154](https://github.com/NibiruChain/nibiru/pull/2154) - fix(evm):
-JSON encoding for the `EIP55Addr` struct was not following the Go conventions and
-needed to include double quotes around the hexadecimal string.
+  JSON encoding for the `EIP55Addr` struct was not following the Go conventions and
+  needed to include double quotes around the hexadecimal string.
 - [#2156](https://github.com/NibiruChain/nibiru/pull/2156) - test(evm-e2e): add E2E test using the Nibiru Oracle's ChainLink impl
 - [#2157](https://github.com/NibiruChain/nibiru/pull/2157) - fix(evm): Fix unit inconsistency related to AuthInfo.Fee and txData.Fee using effective fee
 - [#2159](https://github.com/NibiruChain/nibiru/pull/2159) - chore(evm): Augment the Wasm msg handler so that wasm contracts cannot send MsgEthereumTx

x/evm/embeds/artifacts/contracts/IFunToken.sol/IFunToken.json

@@ -155,6 +155,25 @@
       "stateMutability": "nonpayable",
       "type": "function"
     },
+    {
+      "inputs": [
+        {
+          "internalType": "string",
+          "name": "bankDenom",
+          "type": "string"
+        }
+      ],
+      "name": "getErc20Address",
+      "outputs": [
+        {
+          "internalType": "address",
+          "name": "erc20Address",
+          "type": "address"
+        }
+      ],
+      "stateMutability": "view",
+      "type": "function"
+    },
     {
       "inputs": [
         {

x/evm/embeds/artifacts/contracts/TestERC20TransferThenPrecompileSend.sol/TestERC20TransferThenPrecompileSend.json

@@ -23,6 +23,13 @@ interface IFunToken is INibiruEvm {
         string calldata to
     ) external returns (uint256 sentAmount);
 
+    /// @notice Retrieves the ERC20 contract address associated with a given bank denomination.
+    /// @param bankDenom The bank denomination string (e.g., "unibi", "erc20/0x...", "ibc/...").
+    /// @return erc20Address The corresponding ERC20 contract address, or address(0) if no mapping exists.
+    function getErc20Address(
+        string memory bankDenom
+    ) external view returns (address erc20Address);
+
     struct NibiruAccount {
         address ethAddr;
         string bech32Addr;

x/evm/embeds/artifacts/contracts/TestFunTokenPrecompileLocalGas.sol/TestFunTokenPrecompileLocalGas.json

@@ -12,6 +12,8 @@ import (
 	gethcommon "github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/vm"
 
+	tftypes "github.com/NibiruChain/nibiru/v2/x/tokenfactory/types"
+
 	"github.com/NibiruChain/nibiru/v2/app/keepers"
 	"github.com/NibiruChain/nibiru/v2/eth"
 	"github.com/NibiruChain/nibiru/v2/x/evm"
@@ -40,12 +42,13 @@ func (p precompileFunToken) ABI() *gethabi.ABI {
 }
 
 const (
-	FunTokenMethod_sendToBank  PrecompileMethod = "sendToBank"
-	FunTokenMethod_balance     PrecompileMethod = "balance"
-	FunTokenMethod_bankBalance PrecompileMethod = "bankBalance"
-	FunTokenMethod_whoAmI      PrecompileMethod = "whoAmI"
-	FunTokenMethod_sendToEvm   PrecompileMethod = "sendToEvm"
-	FunTokenMethod_bankMsgSend PrecompileMethod = "bankMsgSend"
+	FunTokenMethod_sendToBank      PrecompileMethod = "sendToBank"
+	FunTokenMethod_balance         PrecompileMethod = "balance"
+	FunTokenMethod_bankBalance     PrecompileMethod = "bankBalance"
+	FunTokenMethod_whoAmI          PrecompileMethod = "whoAmI"
+	FunTokenMethod_sendToEvm       PrecompileMethod = "sendToEvm"
+	FunTokenMethod_bankMsgSend     PrecompileMethod = "bankMsgSend"
+	FunTokenMethod_getErc20Address PrecompileMethod = "getErc20Address"
 )
 
 // Run runs the precompiled contract
@@ -79,6 +82,8 @@ func (p precompileFunToken) Run(
 		bz, err = p.sendToEvm(startResult, contract.CallerAddress, readonly, evm)
 	case FunTokenMethod_bankMsgSend:
 		bz, err = p.bankMsgSend(startResult, contract.CallerAddress, readonly)
+	case FunTokenMethod_getErc20Address:
+		bz, err = p.getErc20Address(startResult, contract)
 	default:
 		// Note that this code path should be impossible to reach since
 		// "[decomposeInput]" parses methods directly from the ABI.
@@ -477,14 +482,12 @@ func (p precompileFunToken) whoAmI(
 	if err := assertContractQuery(contract); err != nil {
 		return bz, err
 	}
-
 	addrEth, addrBech32, err := p.parseArgsWhoAmI(args)
 	if err != nil {
 		err = ErrInvalidArgs(err)
 		return
 	}
-
-	return method.Outputs.Pack([]any{
+	bz, err = method.Outputs.Pack([]any{
 		struct {
 			EthAddr    gethcommon.Address `json:"ethAddr"`
 			Bech32Addr string             `json:"bech32Addr"`
@@ -493,6 +496,7 @@ func (p precompileFunToken) whoAmI(
 			Bech32Addr: addrBech32.String(),
 		},
 	}...)
+	return bz, err
 }
 
 func (p precompileFunToken) parseArgsWhoAmI(args []any) (
@@ -724,6 +728,92 @@ func (p precompileFunToken) bankMsgSend(
 	return method.Outputs.Pack(true)
 }
 
+// getErc20Address implements "IFunToken.getErc20Address"
+// It looks up the FunToken mapping by the bank denomination and returns the associated ERC20 address.
+//
+//	```solidity
+//	function getErc20Address(string memory bankDenom) external view returns (address erc20Address);
+//	```
+func (p precompileFunToken) getErc20Address(
+	start OnRunStartResult,
+	contract *vm.Contract, // Needed for assertContractQuery
+) (bz []byte, err error) {
+	method, args, ctx := start.Method, start.Args, start.CacheCtx
+	defer func() {
+		if err != nil {
+			err = ErrMethodCalled(method, err)
+		}
+	}()
+	// Ensure this is called in a read-only context (like view or pure)
+	if err := assertContractQuery(contract); err != nil {
+		return bz, err
+	}
+
+	bankDenom, err := p.parseArgsGetErc20Address(args)
+	if err != nil {
+		err = ErrInvalidArgs(err)
+		return
+	}
+
+	// Perform lookup using the BankDenom index
+	iterator := p.evmKeeper.FunTokens.Indexes.BankDenom.ExactMatch(ctx, bankDenom)
+	mappings := p.evmKeeper.FunTokens.Collect(ctx, iterator)
+
+	erc20ResultAddress := gethcommon.Address{} // Default to address(0)
+
+	if len(mappings) == 1 {
+		erc20ResultAddress = mappings[0].Erc20Addr.Address
+	} else if len(mappings) > 1 {
+		err = fmt.Errorf(
+			"multiple FunToken mappings found for bank denom \"%s\": %d",
+			bankDenom, len(mappings),
+		)
+		return
+	} else {
+		// No mapping found, erc20ResultAddress remains address(0)
+		err = fmt.Errorf(
+			"no FunToken mapping found for bank denom \"%s\"", bankDenom,
+		)
+		return
+	}
+
+	// Pack the result (either the found address or address(0))
+	return method.Outputs.Pack(erc20ResultAddress)
+}
+
+// parseArgsGetErc20Address parses the arguments for the getErc20Address method.
+// Expected arguments: (string memory bankDenom)
+func (p precompileFunToken) parseArgsGetErc20Address(args []any) (
+	bankDenom string,
+	err error,
+) {
+	if e := assertNumArgs(args, 1); e != nil {
+		err = e
+		return
+	}
+
+	argIdx := 0
+	bankDenom, ok := args[argIdx].(string)
+	if !ok {
+		err = ErrArgTypeValidation("string bankDenom", args[argIdx])
+		return
+	}
+
+	// Validate the bank denomination format using Cosmos SDK validation
+	if err = sdk.ValidateDenom(bankDenom); err != nil {
+		// maybe it's a tf denom
+		tfDenom := tftypes.DenomStr(bankDenom)
+
+		if err = tfDenom.Validate(); err != nil {
+
+			err = fmt.Errorf("invalid bank denomination format: %w", err)
+			return
+		}
+	}
+
+	return bankDenom, nil
+}
+
 func parseArgsBankMsgSend(args []any) (toStr, denom string, amount *big.Int, err error) {
 	if e := assertNumArgs(args, 3); e != nil {
 		err = e