PHP - in_array不能按预期工作[重复]

Although I'm fairly experienced with PHP, I recently meet with this issue which driving me nuts.

    <?PHP
// This code is just basic example
$we_need = array(
    'Carrot',
    'Onion',
    'Milk',
    'Onion',
    'Potato'
); // Notice that Onion is on two places
$basket  = array(); // An empty basket
foreach ($we_need as $product) {
    // Add product to basket ONLY if it's not already there
    if (!in_array($product, $basket)) {
        $basket[] = $product;
    } else {
        echo "For debugging: Duplicate detected, so skipped.
";
    }
}
print_r($basket);
?>

What is wrong with this code? Why $basket array have duplicates at the end?
In my real program, $we_need is fetched from database, but it isn't multidimensional array nor new lines in values.
I know that I can use array_unique() for this approach, but I want to know where the problem is?

</div>

There is a closing bracket missing.

foreach ($we_need as $product) {

    // Add product to basket ONLY if it's not already there
    if (!in_array($product, $basket)) {
        $basket[] = $product;
    } else {
        echo "For debugging: Duplicate detected, so skipped.
";
    } // <<<------- here
}

Then you get:

For debugging: Duplicate detected, so skipped. 
Array ( [0] => Carrot [1] => Onion [2] => Milk [3] => Potato )