Bug: TypeError in Cell.php when $viewName does not contain _cell (PHP 8.4 compatibility issue)

[stalker1980]

PHP Version

8.4

CodeIgniter4 Version

4.6.3

CodeIgniter4 Installation Method

Composer (using codeigniter4/appstarter)

Which operating systems have you tested for this bug?

Linux

Which server did you use?

apache

Database

No response

What happened?

When rendering a view cell whose class name does not contain _cell, CodeIgniter 4 throws a TypeError due to an invalid argument passed to substr().

Steps to Reproduce

Create a View Cell class that does not include _cell in its class name.
Example:

class ProductCard extends \CodeIgniter\View\Cells\Cell
{
    public function render()
    {
        return view('product_card');
    }
}

Call it in a view:

<?= view_cell('App\Cells\ProductCard') ?>

The application throws the TypeError.

Expected Output

CodeIgniter should gracefully handle cases where _cell is not found in $viewName and avoid passing false as a substring length to substr().

Anything else?

After upgrading to PHP 8.4, this line in Cell.php causes a TypeError:

$possibleView1 = $directory . substr($viewName, 0, strrpos($viewName, '_cell')) . '.php';

To prevent the error, it currently has to be written as:

$possibleView1 = $directory . substr($viewName, 0, intval(strrpos($viewName, '_cell'))) . '.php';

Using intval() ensures that false is safely converted to 0, avoiding the type mismatch introduced in PHP 8.4.

[neznaika0]

See #9755 Set fullpath for template:
protected string $view = APPPATH . 'Views/cells/alerts.php';
or
return view(APPPATH . 'Views/cells/alerts.php');

[stalker1980]

Thank you for the suggestion.
However, this issue is not about the full path.
The error occurs because strrpos($viewName, '_cell') returns false when the class name doesn’t contain _cell, which causes substr() to throw a TypeError.
The framework should probably handle that case safely instead of assuming _cell is always present.

[neznaika0]

Maybe. But the first reason is the incorrect use of the filepath.

Thanks for the report, we'll probably fix it.

[michalsn]

Thank you for reporting this! In the future, please double-check that the code you provide actually reproduces the issue 😅

With your render() method, the mentioned error will not be triggered 😉