Advanced Custom Fields plugin User dropdown is not working - php

Question

I am using the ACF plugin in one of the WordPress websites and I have the following configuration for a user dropdown. This is added as a PHP code.
acf_add_local_field_group(array (
'key' => 'group_557ad1ef2b8a1',
'title' => 'Authors',
'fields' => array (
array (
'key' => 'field_557ad24ba99e5',
'label' => 'Featured',
'name' => 'featured_authors',
'type' => 'repeater',
'instructions' => 'Choose a maximum of 6 authors',
'required' => 0,
'conditional_logic' => 0,
'wrapper' => array (
'width' => '',
'class' => '',
'id' => '',
),
'min' => '',
'max' => 6,
'layout' => 'table',
'button_label' => 'Add Author',
'sub_fields' => array (
array (
'key' => 'field_5582bc82f8419',
'label' => 'Author',
'name' => 'featured_authors_author',
'type' => 'user',
'instructions' => '',
'required' => 1,
'conditional_logic' => 0,
'wrapper' => array (
'width' => '',
'class' => '',
'id' => '',
),
'role' => '',
'allow_null' => 0,
'multiple' => 0,
),
),
)
'menu_order' => 0,
'position' => 'normal',
'style' => 'seamless',
'label_placement' => 'top',
'instruction_placement' => 'label',
'hide_on_screen' => array (
0 => 'the_content',
1 => 'author',
2 => 'featured_image',
),
));
Now from the admin section, I am trying to add this field to the page, but it is not permitting the admin to select users. The dropdown is showing without any values. I am using the following versions:
Wordpress - 5.7.3
Advanced Custom Fields - 5.4.5

Answer 1

You have a syntax error in your code. You didn't close the first array() inside the 'fields' parameter in your main list of fields. Before this line:
'menu_order' => 0,
you need to add this:
),
This will close the 'fields' parameter, and allow it to process the parameters that appear after it.
I ended up recreating your field group in the ACF User Interface in the WP Admin, then exported the php, stripped out all the unnecessary/default parameters, and it's working great for me on a test environment. See the code below. I stripped out all of the settings that were just set to the default settings, to help make things a bit more readable.
if( function_exists('acf_add_local_field_group') ):
acf_add_local_field_group(array(
'key' => 'group_6148d6a5d8172',
'title' => 'Authors',
'fields' => array(
array(
'key' => 'field_6148d6afde7ec',
'label' => 'Featured',
'name' => 'featured_authors',
'type' => 'repeater',
'instructions' => 'Choose a maximum of 6 authors',
'max' => 6,
'button_label' => 'Add Author',
'sub_fields' => array(
array(
'key' => 'field_6148d6d5de7ed',
'label' => 'Author',
'name' => 'featured_authors_author',
'type' => 'user',
'required' => 1,
),
),
),
),
'location' => array(
array(
array(
'param' => 'post_type',
'operator' => '==',
'value' => 'post',
),
),
),
'style' => 'seamless',
'hide_on_screen' => array(
0 => 'the_content',
1 => 'author',
2 => 'featured_image',
),
));
endif;
One thing I noticed is that your code doesn't have any Location settings to dictate what post type or other element the field group should appear on, so I set my example to appear on every Post. You may need to adjust this to match your needs.
I also included the if function_exists conditional wrapper so that if you turn off the ACF plugin, it won't generate errors when it cannot find the acf_add_local_field_group() function.