Conditional default field value - use case/description

conditional_default_field_value.adoc

I have added a Boolean authorized field to my I8 taxonomy terms via a lyrasis_module_entity_base_field_info function in my custom module. Currently the default value of this field is FALSE.

Many (but not all) of my vocabularies also have a URI external_vocabulary_uri field.

What I would like to be able to do is:

• if there is an external_vocabulary_uri field on my taxonomy term AND if there is a value in that field, the value of authorized field gets set to TRUE automatically

• otherwise, value of authorized field remains FALSE unless a user sets it to TRUE. If this field value gets set to TRUE, it does not ever get "automagically" set back to FALSE, but may be changed back to FALSE manually by a user, or by explicit batch change, etc.

Note:

• When a new term form is opened, there is no external_vocabulary_uri value. It will be entered by the user. So it seems like something needs to happen to change the value of authorized on form save?

• If existing term with external_vocabulary_uri value is edited via form, and the existing authorized value = TRUE, and the edits include clearing the external_vocabulary_uri field (deleting its value), the value of authorized should NOT be changed to FALSE on save of form.

Not sure if this is possible, where to do it, or what the right search terms are to find out. The conditional fields module seems to be for something different.

Any pointers?