FieldConfigEditForm defines an third_party_settings element so that third party configuration settings can be set by fields or other alters.
$form['settings'] += $item->fieldSettingsForm($form, $form_state);
$form['third_party_settings'] = [
'#tree' => TRUE,
'#weight' => 11,
];
FieldStorageConfigEditForm does not. Since FieldStorageConfigEditForm is a subform, it's near impossible to add a custom submit handler for adding third party settings to the field storage configuration entity.
Alter the field_storage_edit_form and try to save third party settings.
Follow the same pattern.
$form['settings'] += $item->storageSettingsForm($form, $form_state, $this->entity->hasData());
$form['third_party_settings'] = [
'#tree' => TRUE,
'#weight' => 11,
];
Needs work
11.0 🔥
The change is currently missing an automated test that fails when run with the original code, and succeeds when the bug has been fixed.
Gone back n forth if this is small enough to not need tests but seems like something maybe we could extend an existing test?