When QLineEdit::editingFinished is connected such:

connect(ui->lineEdit, &QLineEdit::editingFinished, [this](){
        QMessageBox::warning(this, "There can be ...", "... only one!");
    });

the signal should not be re-emitted while still in the slot. ( Maybe even until the text is changed again by the user )

To reproduce:

• Compile attached example
• Enter text in LineEdit
• Click outside the application window so it loses focus
• Once the messagebox appears, click outside the app window / message box again

Expected:

• Only one message box is shown, no matter how often focus is changed

Actual

• Everytime the app loses focus, another message box is opened