refactor(staking): do not execute write functions on staticcall

precompiles/staking/staking.go

@@ -380,7 +380,7 @@ func (c *Contract) MoveStake(
 
 // Run is the entrypoint of the precompiled contract, it switches over the input method,
 // and execute them accordingly.
-func (c *Contract) Run(evm *vm.EVM, contract *vm.Contract, _ bool) ([]byte, error) {
+func (c *Contract) Run(evm *vm.EVM, contract *vm.Contract, readOnly bool) ([]byte, error) {
 	method, err := ABI.MethodById(contract.Input[:4])
 	if err != nil {
 		return nil, err
@@ -415,6 +415,12 @@ func (c *Contract) Run(evm *vm.EVM, contract *vm.Contract, _ bool) ([]byte, erro
 		}
 		return res, nil
 	case StakeMethodName:
+		if readOnly {
+			return nil, ptypes.ErrUnexpected{
+				Got: "method not allowed in read-only mode: " + method.Name,
+			}
+		}
+
 		var res []byte
 		execErr := stateDB.ExecuteNativeAction(contract.Address(), nil, func(ctx sdk.Context) error {
 			res, err = c.Stake(ctx, evm, contract, method, args)
@@ -425,6 +431,12 @@ func (c *Contract) Run(evm *vm.EVM, contract *vm.Contract, _ bool) ([]byte, erro
 		}
 		return res, nil
 	case UnstakeMethodName:
+		if readOnly {
+			return nil, ptypes.ErrUnexpected{
+				Got: "method not allowed in read-only mode: " + method.Name,
+			}
+		}
+
 		var res []byte
 		execErr := stateDB.ExecuteNativeAction(contract.Address(), nil, func(ctx sdk.Context) error {
 			res, err = c.Unstake(ctx, evm, contract, method, args)
@@ -435,6 +447,12 @@ func (c *Contract) Run(evm *vm.EVM, contract *vm.Contract, _ bool) ([]byte, erro
 		}
 		return res, nil
 	case MoveStakeMethodName:
+		if readOnly {
+			return nil, ptypes.ErrUnexpected{
+				Got: "method not allowed in read-only mode: " + method.Name,
+			}
+		}
+
 		var res []byte
 		execErr := stateDB.ExecuteNativeAction(contract.Address(), nil, func(ctx sdk.Context) error {
 			res, err = c.MoveStake(ctx, evm, contract, method, args)