More flexible conditional fields

Make sure that:
- The user you are currently logged in has the 'administer conditional fields' access
- The fields that you want to set as controlling fields have allowed values

If the above are OK and the field settings are still not appearing, could you please export the field settings using the content_export.module and attach them?

Thanks

There are many limitations to the conditional fields one can assign, but I though it was better to release a limited initial version and maybe add flexibility later.

Limitations:

1. If the field is not inside a group, it can control groups and fields outside groups
2. If a field is inside a group, it can control fields inside the same group
3. A field cannot be a controlling and a controlled field at the same time.
4. A field or a group can only be controlled by one field at a time.

While these could all be considered bugs (especially the latter), I had to enforce these because they would add great complexity both to the form validation code and to the javascript.

E.g.:
In the case you are asking:
what happens when:
'a' (not in a group) controls the group 'b'
'c' (not in a group) controls the field 'd' (in group 'b')

If 'c' is triggered, but 'a' is not triggered, 'd' would be invisible, but still be considered triggered (and as such, require validation)

Almost all the problems arise from the fact that basic form validation (which is done by _form_validate) is not overridable. If we could find a way to skip _form_validation for fields that weren't activated, all would be simpler.

ps: explainfield is great, but I resolved to code this because I needed more flexibility, and when I had more flexibility, I found that I needed even more, and more...

Changing the category, as this should be considered a feature request.

There are now open issues on more specific features, like this: #344689: Nested conditional fields.