Test1

In PHP, the condition if (!$amount || !$transactionId || !$playerId) checks whether any of the variables ($amount, $transactionId, or $playerId) evaluate to false.

Since PHP treats 0, null, false, '' (empty string), and [] (empty array) as falsy values, the check !$amount will be true if $amount is 0.

What this means in your case:

• If $amount is 0, !$amount will be true, and the function will return the error response.
• If $amount is null, !$amount will be true, and it will return the error response.
• If $amount is any other falsy value (like an empty string), it will also trigger the return.

How to fix it if 0 should be allowed:

If you want to allow $amount to be 0 but still check for null or empty values, modify the condition like this: