empty and isset do not work with API objects

[louismrose]

Expected Behaviour

$job = $this->client()->jobs->get(1234)->waitForCompletion();
count($job->target_files); // returns 1

empty($job->target_files); // should return true
isset($job-> target_files); // should return false

Current Behaviour

$job = $this->client()->jobs->get(1234)->waitForCompletion();
count($job->target_files); // returns

empty($job->target_files); // returns false
isset($job-> target_files); // returns true

Possible Solution

This looks to be an instance of php/php-src#19036

ZamzarObject should probably implement __isset as well as __get.

Steps to Reproduce

1. Create an API job that returns >1 target file.
2. Run the code in the "expected behaviour section"
3. Observe that empty($job->target_files) and isset($job-> target_files) return the wrong values

Environment

• zamzar-php 2.1.1
• PHP 7.2.34

[louismrose]

The fix is a potentially breaking change as clients might be depending on the (unidiomatic) behaviour of empty / isset on Zamzar API objects.

We'll therefore target a fix in the next major release of the library.

Our advice in the meantime is to avoid using empty or isset when accessing magic properties on all Zamzar API objects defined in 2.x versions of this library.