page.ChangeSlug:before returns null for the page object

The CMS Questions
1

Hi,

I’m playing around with the page.ChangeSlug:before hook:

'page.changeSlug:before' => function(Kirby\Cms\Page $oldPage, string $newSlug, string $languageCode) {

    $oldSlug = $oldPage->slug();
    //...
}

However, when changing a slug to test the setup, I always get this error:

Error: Kirby\Cms\App::{closure}(): Argument #1 ($oldPage) must be of type Kirby\Cms\Page, null given

Why is the parameter passed for the page object null?

Cheers,

Stefan

2

Hooks use named arguments since Kirby 3.4, and the variable names in your code don’t match those (looks like old code from pre-3.4). See page.changeSlug:before | Kirby CMS …i.e. should be function (Kirby\Cms\Page $page, string $slug, string $languageCode) instead.

3

So, the parameters names $page, $slug, and $languageCode cannot be changed. Is that correct?

4

Correct. That applies to all hooks. Since 3.4 the arguments are detected by name and no longer by order as before – they receive null if the variable name doesn’t match.

1 Like
5

Understood, thanks.

I copied the line from the documentation for page.changeSlug:before and tested again:

'page.changeSlug:before' => function (Kirby\Cms\Page $page, string $slug, string $languageCode) {
//...
}

But now something appears to be wrong with the third argument:

Error: Kirby\Cms\App::{closure}(): Argument #3 ($languageCode) must be of type string, null given

Could it be that the documentation and the real code don’t match? Or did I make a mistake somewhere?

6

You’re right, should be like that:

'page.changeSlug:before' => function (Kirby\Cms\Page $page, string $slug, ?string $languageCode = null) { }
7

I’ve fixed the hook arguments:

1 Like
8

Now it’s working. Thanks a lot!