feat: expose governance authority address via precompile query

contracts/solidity/precompiles/gov/IGov.sol

@@ -274,5 +274,15 @@ interface IGov {
     /// @dev getConstitution returns the current constitution.
     /// @return constitution The current constitution
     function getConstitution() external view returns (string memory constitution);
+
+    /// @dev getAuthority returns the governance module account address.
+    /// This address must be used as the `authority` field in parameter-change
+    /// and software-upgrade proposal messages.
+    /// @return authorityBech32 The governance module account address in Bech32 format
+    /// @return authorityHex The governance module account address as an EVM address
+    function getAuthority()
+        external
+        view
+        returns (string memory authorityBech32, address authorityHex);
 }
 

contracts/solidity/precompiles/testutil/contracts/GovCaller.sol

@@ -130,6 +130,14 @@ contract GovCaller {
         return gov.GOV_CONTRACT.getParams();
     }
 
+    function getAuthority()
+        external
+        view
+        returns (string memory authorityBech32, address authorityHex)
+    {
+        return gov.GOV_CONTRACT.getAuthority();
+    }
+
     function testDepositWithTransfer(
         uint64 _proposalId,
         types.Coin[] calldata _deposit,

precompiles/gov/IGov.sol

@@ -274,5 +274,15 @@ interface IGov {
     /// @dev getConstitution returns the current constitution.
     /// @return constitution The current constitution
     function getConstitution() external view returns (string memory constitution);
+
+    /// @dev getAuthority returns the governance module account address.
+    /// This address must be used as the `authority` field in parameter-change
+    /// and software-upgrade proposal messages.
+    /// @return authorityBech32 The governance module account address in Bech32 format
+    /// @return authorityHex The governance module account address as an EVM address
+    function getAuthority()
+        external
+        view
+        returns (string memory authorityBech32, address authorityHex);
 }
 

precompiles/gov/abi.json

@@ -1103,5 +1103,23 @@
     ],
     "stateMutability": "nonpayable",
     "type": "function"
+  },
+  {
+    "inputs": [],
+    "name": "getAuthority",
+    "outputs": [
+      {
+        "internalType": "string",
+        "name": "authorityBech32",
+        "type": "string"
+      },
+      {
+        "internalType": "address",
+        "name": "authorityHex",
+        "type": "address"
+      }
+    ],
+    "stateMutability": "view",
+    "type": "function"
   }
 ]

precompiles/gov/gov.go

@@ -141,6 +141,8 @@ func (p Precompile) Execute(ctx sdk.Context, stateDB vm.StateDB, contract *vm.Co
 		bz, err = p.GetParams(ctx, method, contract, args)
 	case GetConstitutionMethod:
 		bz, err = p.GetConstitution(ctx, method, contract, args)
+	case GetAuthorityMethod:
+		bz, err = p.GetAuthority(ctx, method, contract, args)
 	default:
 		return nil, fmt.Errorf(cmn.ErrUnknownMethod, method.Name)
 	}

precompiles/gov/query.go

@@ -1,10 +1,17 @@
 package gov
 
 import (
+	"fmt"
+
 	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/vm"
 
+	cmn "github.com/cosmos/evm/precompiles/common"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
+	govtypes "github.com/cosmos/cosmos-sdk/x/gov/types"
 )
 
 const (
@@ -26,6 +33,8 @@ const (
 	GetParamsMethod = "getParams"
 	// GetConstitutionMethod defines the method name for the get constitution precompile request.
 	GetConstitutionMethod = "getConstitution"
+	// GetAuthorityMethod defines the method name for the get authority precompile request.
+	GetAuthorityMethod = "getAuthority"
 )
 
 // GetVotes implements the query logic for getting votes for a proposal.
@@ -233,3 +242,31 @@ func (p *Precompile) GetConstitution(
 
 	return method.Outputs.Pack(res.Constitution)
 }
+
+// GetAuthority returns the governance module account address in both
+// Bech32 and EVM hex formats. This address must be used as the `authority`
+// field in parameter-change and software-upgrade proposal messages.
+func (p *Precompile) GetAuthority(
+	ctx sdk.Context,
+	method *abi.Method,
+	_ *vm.Contract,
+	args []interface{},
+) ([]byte, error) {
+	if len(args) != 0 {
+		return nil, fmt.Errorf(cmn.ErrInvalidNumberOfArgs, 0, len(args))
+	}
+
+	// Derive the governance module account address.
+	moduleAddr := authtypes.NewModuleAddress(govtypes.ModuleName)
+
+	// Convert to Bech32 string using the chain's account prefix.
+	authorityBech32, err := p.addrCdc.BytesToString(moduleAddr.Bytes())
+	if err != nil {
+		return nil, fmt.Errorf("failed to encode authority address: %w", err)
+	}
+
+	// Convert to EVM hex address.
+	authorityHex := common.BytesToAddress(moduleAddr.Bytes())
+
+	return method.Outputs.Pack(authorityBech32, authorityHex)
+}