I have made some test and it seems that ACF calls get_option() when the block inserted into the content does not actually contain the field keys predicted during registration via acf_add_local_field_group().
It happens when I save an empty block or a block with hidden fields.
So when I add an empty block which looks within the code like:
<!-- wp:acf/header {"id":"block_5c8ac410e890e","name":"acf/header","align":"","mode":"edit"} /-->
the plugin looks for the missing fields in wp_options table, for example:
SELECT option_value
FROM wp_options
WHERE option_name = 'block_5c8ac410e890e_my-header-content'
LIMIT 1
where my-header-content is the name of a field type group in this case.
It’s quite surprising for me – why ACF thinks that I store any block data in wp_options?
Then, when I add some content into the subfield of my-header-content field, the plugin no longer queries wp_options for my-header-content and the block structure grows into:
<!– wp:acf/header {“id”:”block_5c8ac410e890e”,”data”:{“field_my-header-content”:{“field_my-header-content-lead”:”This is our lead”,”field_my-header-content-text”:””},”field_my-header-aside”:{“field_my-header-aside-settings”:””},”field_my-header-background”:{“field_my-header-background-image”:””,”field_my-header-background-video”:””,”field_my-header-background-color”:”white”,”field_my-header-background-has-pattern”:”0″}},”name”:”acf/header”,”align”:””,”mode”:”edit”} /–>
Well, after all I think I’ll report it on Github…
