Just a heads up for anyone that may have done the same in the past.
Working on upgrading plugins I noticed a difference in the requirements for field keys. Field keys in ACF5 must start with “field_” whereas in ACF4 this could be changed. When building a plugin I would generally alter the field key to begin with an underscore which would those fields from the custom fields field selector.
However, since the field key values no longer appear to be stored in the postmeta table, or anywhere for that matter, I don’t suppose I need to do that any more.
I find that extremely interesting. For example, this is a field I created for a plugin for ACF4
array('key' => '_acf_key_acfop_menu',
'label' => 'Menu Text',
'name' => '_acfop_menu',
'type' => 'text',
'instructions' => 'Will default to title if left blank.',
'default_value' => '',
'placeholder' => '',
'prepend' => '',
'append' => '',
'formatting' => 'none',
'maxlength' => '')
I was thinking to myself… “It would be nice if all those fields didn’t appear in the ‘Custom Fields’ drop down in WP”… so I tried changing them to start with an underscore. When that worked I just started changing the “key” value to whatever I wanted and that worked.
If this is a bug in ACF4 I would ask that it’s a bug you ignore. 😛