Use empty() instead of negation for result validation

[zigzagdev]

Propose

• Fix result validation

why

This change replaces a simple negation check with empty() to ensure empty arrays
are also treated as failure in result validation logic. Because I felt that using a simple ! condition makes it ambiguous as to what values are actually being evaluated as falsy.

[LordSimal]

We purposely don't use empty() that often because it can cause weird side effects.
See https://dev.to/klnjmm/never-use-empty-function-in-php-4pb0 for example

As you can see in https://3v4l.org/A1TGS#vnull an empty array is still falsey, so empty arrays are already rejected by default.

Your bug seems to be related to something different.