Fatal error: Uncaught Error: [] operator not supported for strings – PHP 7.1

I suspect this might be caused by another module or even the theme. It's common for people to make $variables['options']['attributes']['class'] a string when it really needs to be an array.

Please try this.

As described in the comment, the patch in #4 attempts to fix the problem of a site which is adding a class attribute as a string rather than an array.

However, the problem remains for PHP 7.1 and above for this line:

$variables['options']['attributes']['tabindex'][] = '0';

This line is still applying an empty index operator to a string, which is disallowed per https://www.php.net/manual/en/migration71.incompatible.php

Applying the empty index operator to a string (e.g. $str[] = $x) throws a fatal error instead of converting silently to array.

An additional problem with this line is that it will override any tabindex values sent to it by the l() function. There are valid scenarios where the <nolink> render should not be focusable.

The design of adding a tabindex to a span tag is understandable, so that it behaves similar to a link. However, this behavior should be the fallback, not the the only possibility.

We have a use case, for example, where we have adjacent links that point to the same destination, so for accessibility reasons, we want to set the tabindex to -1, as shown below:

  $link_options = [
    'attributes' => [
      'class' => ['cta'],
      'aria-hidden' => 'true',
      'tabindex' => '-1',
    ],
  ];
  $variables['read_more'] = (!empty($variables['link'])) ? l($default, $variables['link'], $link_options) : FALSE;

In short, this module should respect the tabindex value, if it is already provided, and if not, it can fallback to a 0 value that is not cast to array.

The attached patch includes the fix in #4 (see interdiff) and additionally fixes the tabindex fallback, while wrapping it in a conditional that will respect an existing value.

Thanks for reporting this.

Regarding the class attribute: This is not a bug of this module. Class must be an array as specified in the core documentation of theme_link function: https://api.drupal.org/api/drupal/includes%21theme.inc/function/theme_link/7.x

class: must be declared in an array. Example: 'class' => array('class_name1','class_name2').

I prefer not to "babysit" other modules/themes which does not follow documentation.

However I will take a look at the second problem (tabindex), which seems valid.

Committed and fixed the problem with tabindex. Thanks all!

I plan to roll-out a new release with few fixes from today soon.