Once function runs repeatedly if cached value is null

[AEM5299]

Laravel Version

11.8.0

PHP Version

8.2

Database Driver & Version

No response

Description

The once function does not use cached value when it's null. This is because of the use of isset here.

If you run the function provided below 2 times, the callback will run twice. I would expect it to only once. I can open a fix PR if you can confirm this is not intended behaviour.

Steps To Reproduce

public function calculate()
{
    return once(function () {
        echo 'once';

        return null;
    });
}

[rodrigopedra]

I added this sample console command to a newly created Laravel project:

<?php // ./routes/console.php

use Illuminate\Support\Facades\Artisan;

Artisan::command('app:test', function () {
    $foo = new class {
        public function calculate()
        {
            return once(function () {
                echo 'once';

                return null;
            });
        }
    };

    $foo->calculate();
});

And ran these commands:

$ php artisan --version
Laravel Framework 11.14.0

$ php artisan cache:clear

   INFO  Application cache cleared successfully.  


$ php artisan app:test
once

Can you provide additional information on how to reproduce it?

On the linked source code, although I think using array_key_exists() instead of isset() would allow caching of null values, there is nowhere where the callback would be called twice.

As you are using Laravel 11.8.0 instead of 11.14.0, would you care to update your project and check if the issue persists?

[AEM5299]

<?php // ./routes/console.php

use Illuminate\Support\Facades\Artisan;

Artisan::command('app:test', function () {
    $foo = new class {
        public function calculate()
        {
            return once(function () {
                echo 'once';

                return null;
            });
        }
    };

    $foo->calculate();
    $foo->calculate();
});

Running the above will echo 'once' twice, where it should have cached the result and not run the callback a second time.

Same bug still exists in Laravel v11.14.0

[rodrigopedra]

Ah ok, now I see it, thanks for clarifying =)

[rodrigopedra]

I guess it is safe to send a PR, this doesn't seem like intentional behavior by any means. Specially if a given callback runs a costly operation.

I have it working as expected with these changes, just in case:

public function value(Onceable $onceable)
{
    if (! static::$enabled) {
        return call_user_func($onceable->callable);
    }

    $object = $onceable->object ?: $this;

    $hash = $onceable->hash;

    if (! isset($this->values[$object])) {
        $this->values[$object] = [];
    }

    if (array_key_exists($hash, $this->values[$object])) {
        return $this->values[$object][$hash];
    }

    return $this->values[$object][$hash] = call_user_func($onceable->callable);
}

[driesvints]

Thanks. I'm not 100% sure if the null value return was intended to be cached. Feel free to attempt that PR 👍