PHP 8.0 compatibility

see patch

Tested with charts 3.x dev and this patch, no more errors running php 8.0

tested my own patch, it's ready

not quite ready yet

try this one

here's a better patch
and interdiff

code sniffer fixes also

I just sponsored this project 50 USD$

Hope this patch makes it into a tagged 3.x release soon!

Thanks

this "might" help the php 8.0 D9 tests, not sure.

Yet another

Ok patch 14 (in comment 13) looks like it's the one.

The only thing I am curious of is if we change this in the tests:

          $default_value = '';
          if (isset($options['data_fields'][$field_name])) {
            $default_value = $options['data_fields'][$field_name];
          }

To this:

          $default_value = NULL;
          if (isset($options['data_fields'][$field_name])) {
            $default_value = $options['data_fields'][$field_name];
          }

and see if the tests still pass.

I also fixed some code sniffer style changes as you'll maybe notice in the patch.

added some child issues for followup

*** EDIT ***

No rush, but would be nice to have a tagged release

*** EDIT ***

Please tag and release when you have a chance! Thanks :)

@andileco, thanks so much for this, I have one more favor to ask you, please add php 8.0 to the test default to replace php 7.2, we should only have to test php 7.4, php 8.0 and php 8.1 because in a few days from now PHP 7.3 will be "End of Life"
https://www.drupal.org/node/232629/qa
Drupal 8 will also be EOL soon therefore all tests should cover Drupal 9.2.x and 9.3.x, php 7.4 and php 8.0 (and 8.1)