Inconsistent return type of getLabel

[dakujem]

Version: 3.*

Problem description

For some reason, CheckBox, HiddenField and Button have no label by default. But the other inputs do have labels.

What If we did want our checkboxes to actually have a label? And render it like a label of the other elements? (For design consistency or any other reason.)

Of course I know manual rendering could be used. But why?

Or we wanted to make it Bootstrap-compatible (render the input outside of <label> tag)?

If anyone could make Nette forms use their own implementation of Checkbox ... but we can't, since in order to use addCheckbox method we need to return an instance of Nette\Forms\Control\Checkbox and since its getLabel method is defined as public function getLabel($caption = null): void there is no way to force any other return type on it...

Possible solution

1. drop void return type on Checkbox::getLabel method.
2. implement a mechanism to allow users to be able to select how they want the label be rendered.

In Nette 2.4 we have solved this elegantly this way (one is able to chose from 3 different styles of how getControl and getLabel return their values):

    public function getControl()
    {
        $flag = $this->getLabelRenderFlag();

        // label and control wrapped together
        if ($flag === self::LABEL_NETTE_STYLE) {
            return $this->parent_getControl();
        }

        // wrap label and label separately
        if ($flag === self::LABEL_SEPARATE_WRAPPER) {
            $this->getSeparatorPrototype()->addHtml($this->getControlPart());
            $this->getSeparatorPrototype()->addHtml($this->getLabelPart());
            return $this->getSeparatorPrototype();
        }

        // only control part returned (label is rendered separately)
        return $this->getSeparatorPrototype()->addHtml($this->getControlPart());
    }

    public function getLabel($caption = null)
    {
        // label is not rendered
        if ($this->getLabelRenderFlag() !== self::LABEL_STANDALONE) {
            return parent::getLabel($caption);
        }

        // render label separately
        return $this->getLabelPart();
    }

I'm open to providing a PR for the above code.

---

Please also consider dropping the return type of the other methods, for consistency sake, even though it makes less sense to override labels of these methods:

• RadioList::getLabel
• HiddenField::getLabel
• Button::getLabel

[dakujem]

Awesome! Thanks a lot.

How about RadioList's Html return type?

[dg]

I think it is correct "covariant type":https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)#Covariant_method_return_type.

[dakujem]

Any return type is covariant to "not specified". 🤷‍♂️

Anyway, it limits extensibility and breaks consistency.

BUT hey, we are at least able to return any string (including empty strings) wrapped inside Html objects, so it's no biggie. 👍
Thanks for the other changes, appreciated.

[dg]

It is specified

forms/src/Forms/Controls/BaseControl.php

Line 269 in fdedfc2

* @return Html|string|null