Here’s the context. I’m working on a Qt application that draws stuff. At some point, the logic may require to perform a rotation or a translation of the scene in order to draw specific objects, given that this rotation and/or translation should necessarily be reset before drawing other objects.

Recently, I found a bug where the objects weren’t drawn correctly. I ended up by finding the cause, in the piece of code which looks like this:

void example(const QString &text) {
    ...  // A few lines of code.

    this->setRotation(angle);

    ...  // A few lines of code.

    if (text.trimmed().length() == 0) {
        return;
    }

    ...  // A few more lines of code.

    this->resetRotation();
}

The error was that I forgot to call resetRotation before the return in the if block.

What would be an idiomatic way, in modern C++, to prevent such cases from happening?

RAII-like pattern comes into mind, and I could imagine for setRotation to return an object which would automatically call resetRotation in its destructor—just like std::unique_ptr does with the pointer it holds. This, however, doesn’t seem particularly clear from the perspective of the caller of setRotation. One may be forced to create a variable to store the actual result of setRotation if [[nodiscard]] attribute is used, but having a variable which has no other purpose than the cleanup (and which won’t be called) would, I suppose, look weird.

Does it?

What are the alternatives?