Add checks for context attributes

[codechefmarc]

Summary

Note: This was already approved and merged in emulsify_twig as part of PR-61

The changes didn't make their way into emulsify_tools.

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The fix includes a check of $context['attributes'] to see if it exists and if not, create a new Attribute(). If it did exist in the first place, a secondary check makes sure that if it's an array, to create an Attribute object from that array.

This fix is based on issues reported on the Drupal.org issue queue:

• https://www.drupal.org/project/emulsify_twig/issues/3160391
• https://www.drupal.org/project/emulsify_twig/issues/3302662
• https://www.drupal.org/project/emulsify_twig/issues/3210140

Fixes

• Checks $context['attributes'] to see if it exists and if not, create a new Attribute().
• If $context['attributes'] did exist in the first place, a secondary check makes sure that if it's an array, to create an Attribute object from that array.

Explain the motivation for making this change. What existing problem does the pull request solve?

Sometimes the $context variable does not supply attributes as per https://www.drupal.org/project/emulsify_twig/issues/3160391

Because of this, there are times when it was assumed to be an Attribute object and therefore would throw errors as per https://www.drupal.org/project/emulsify_twig/issues/3210140

Finally, there could be times when the $context['attributes'] is an array. If so, it should be converted to an Attribute object based on that array as per https://www.drupal.org/project/emulsify_twig/issues/3302662

Documentation update (required)

None - this is an internal change only.

How to review this pull request

• One method that caused these errors was by calling the twig_render_template function as was mentioned in https://www.drupal.org/project/emulsify_twig/issues/3210140. This can be replicated with updated code:

function MY_THEME_preprocess_page(&$variables) {
  $markup = twig_render_template(\Drupal::service('extension.list.theme')->getPath('MY_THEME') . '/templates/content/node.html.twig', ['content' => 'test content']);
}

The output above doesn't necessarily need to be actually rendered, just this call did produce the error prior to this fix.

• Other ways of testing this could include testing content using templates with bem and add_attributes in use, inside views, views with Ajax pagers, and search results pages - essentially places that aren't "typical" view modes.

Closing issues

Closes Drupal.org issues listed above.

[callinmullaney]

@codechefmarc Additional $context checks look good to me. Feel free to merge and cut a release to d.o.