Why is the action wp_ajax_wp_link_ajax not using wp_send_json()

[stephanh]

The action now returns an array with results with the header content-type text/html
Should this not be application/json as achieved by the wp_send_json() function?

https://core.trac.wordpress.org/browser/tags/5.3.2/src/wp-admin/includes/ajax-actions.php#L1863

[sabernhardt]

This could use some testing by someone who understands it better than I do :)

Next time, please create a patch from the root directory, but 49408.patch​ does apply to src.

The code for the wp_ajax_wp_link_ajax was added in 3.1 (changeset:16459), and wp_send_json was created for 3.5. So that's likely why it is not used yet.

## Summary\n\n- Use wp_send_json() for wp_ajax_wp_link_ajax() responses.\n- Add regression coverage for the JSON content type and response payload.\n\nTrac: https://core.trac.wordpress.org/ticket/49408\n\n## Testing\n\n- PHPCBF\n- PHPCS\n- PHP syntax checks\n- PHPUnit blocked locally because the Docker MySQL host is unavailable.