Calling Parent Contracts (Solidity Code Example)

Parent contracts can be called directly, or by using the keyword super.

By using the keyword super, all of the immediate parent contracts will be called.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.26;

/* Inheritance tree
   A
 /  \
B   C
 \ /
  D
*/

contract A {
    // This is called an event. You can emit events from your function
    // and they are logged into the transaction log.
    // In our case, this will be useful for tracing function calls.
    event Log(string message);

    function foo() public virtual {
        emit Log("A.foo called");
    }

    function bar() public virtual {
        emit Log("A.bar called");
    }
}

contract B is A {
    function foo() public virtual override {
        emit Log("B.foo called");
        A.foo();
    }

    function bar() public virtual override {
        emit Log("B.bar called");
        super.bar();
    }
}

contract C is A {
    function foo() public virtual override {
        emit Log("C.foo called");
        A.foo();
    }

    function bar() public virtual override {
        emit Log("C.bar called");
        super.bar();
    }
}

contract D is B, C {
    // Try:
    // - Call D.foo and check the transaction logs.
    //   Although D inherits A, B and C, it only called C and then A.
    // - Call D.bar and check the transaction logs
    //   D called C, then B, and finally A.
    //   Although super was called twice (by B and C) it only called A once.

    function foo() public override(B, C) {
        super.foo();
    }

    function bar() public override(B, C) {
        super.bar();
    }
}