Call state modifying function in view function

Question

Is it somehow possible to do something like this?

contract Test {
    function test (bool isTransaction) public view {
        if (isTransaction) {
          foo();
        }

        ...
    }
    
    function foo () public {
        ...
    }
}

In the best case I would be able to call test() like an usual view/pure function without the need of making a transaction but if isTransaction is true test() requires me to make a transaction in order to call it. Maybe I can throw an exception or something similar to be able to compile and run this code?

EDIT: bool transaction got bool isTransaction

Answer 1

You can accomplish something like this using staticcall:

contract Test {
  function test (bool transaction) public view {
    if (transaction) {
      (bool success,) = address(this).staticcall(abi.encodeWithSignature("foo()"));
      require(success, "Contract call failed");
    }
  }
    
  function foo () public {
    // ...
  }
}

This will compile, and test will execute without errors as long as foo() does not modify the state. If foo() does modify state, it will revert because success is false.

Answer 2

the answer is no. it will not compile

view functions cannot modify the state and the compiler check this and give you back

TypeError: Function declared as view, but this expression (potentially) modifies the state

Tested it with solidity 0.8.3