[5.4] Arr::pluck - handle situation when itemKey is an object

[crlcu]

When using pluck on a collection who's items are Eloquent models and some of the fields are casted as date an error is thrown:

[2017-06-30 11:20:34] local.ERROR: ErrorException: Illegal offset type in /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Support/Arr.php:365
Stack trace:
#0 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Support/Arr.php(365): Illuminate\Foundation\Bootstrap\HandleExceptions->handleError(2, 'Illegal offset ...', '/var/www/html/t...', 365, Array)
#1 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Support/Collection.php(689): Illuminate\Support\Arr::pluck(Array, Array, Array)
#2 /var/www/html/tpt/app/Console/Commands/Test.php(48): Illuminate\Support\Collection->pluck('id', 'start_at')
#3 [internal function]: App\Console\Commands\Test->handle()
#4 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(29): call_user_func_array(Array, Array)
#5 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(87): Illuminate\Container\BoundMethod::Illuminate\Container\{closure}()
#6 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Container/BoundMethod.php(31): Illuminate\Container\BoundMethod::callBoundMethod(Object(Illuminate\Foundation\Application), Array, Object(Closure))
#7 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Container/Container.php(531): Illuminate\Container\BoundMethod::call(Object(Illuminate\Foundation\Application), Array, Array, NULL)
#8 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Console/Command.php(182): Illuminate\Container\Container->call(Array)
#9 /var/www/html/tpt/vendor/symfony/console/Command/Command.php(264): Illuminate\Console\Command->execute(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))
#10 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Console/Command.php(167): Symfony\Component\Console\Command\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Illuminate\Console\OutputStyle))
#11 /var/www/html/tpt/vendor/symfony/console/Application.php(835): Illuminate\Console\Command->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#12 /var/www/html/tpt/vendor/symfony/console/Application.php(200): Symfony\Component\Console\Application->doRunCommand(Object(App\Console\Commands\Test), Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#13 /var/www/html/tpt/vendor/symfony/console/Application.php(124): Symfony\Component\Console\Application->doRun(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#14 /var/www/html/tpt/vendor/laravel/framework/src/Illuminate/Foundation/Console/Kernel.php(122): Symfony\Component\Console\Application->run(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#15 /var/www/html/tpt/artisan(35): Illuminate\Foundation\Console\Kernel->handle(Object(Symfony\Component\Console\Input\ArgvInput), Object(Symfony\Component\Console\Output\ConsoleOutput))
#16 {main}  

This commit is meant to fix this issue.

[taylorotwell]

Why would we convert them to strings?

[crlcu]

Because the key can either be an integer or a string, if the key is something else, in this case a Carbon object, an error is thrown.

[Douglasdc3]

This code will only work if the given class implements the magic __toString method otherwise it will throw PHP Error with the following test cases:

public function testPluckWithStdClass()
{
    $array = [
        ['start' => new \stdClass, 'end' => new \stdClass],
    ];
    Arr::pluck($array, 'end', 'start');
}

public function testPluckWithClass()
{
    $array = [
        ['start' => new Arr(), 'end' => new Arr()],
    ];
    Arr::pluck($array, 'end', 'start');
}

Output:

There were 2 errors:

1) Illuminate\Tests\Support\SupportArrTest::testPluckWithStdClass
Object of class stdClass could not be converted to string

/Users/kenandries/development/laravel/19838/src/Illuminate/Support/Arr.php:384
/Users/kenandries/development/laravel/19838/tests/Support/SupportArrTest.php:388

2) Illuminate\Tests\Support\SupportArrTest::testPluckWithClass
Object of class Illuminate\Support\Arr could not be converted to string

/Users/kenandries/development/laravel/19838/src/Illuminate/Support/Arr.php:384
/Users/kenandries/development/laravel/19838/tests/Support/SupportArrTest.php:396

From the php documentation: Since PHP 5.2.0, converting objects without __toString() method to string would cause E_RECOVERABLE_ERROR