Suppose I have two content typs, "Job Listing" and "Job Application". A job application has a field (using the CCK module) to reference the job listing (a required field). Suppose the job application has a field "Status" with values like "new", "accepted", "rejected".
I would like to set permissions so that the job application status can only be set by the creator of the job listing it corresponds to. If there is an addon that can do this great. I would also like general direction as to how a custom addon might implement this.
(I am following the scenario in Ch. 3 of O'Reilly's "Using Drupal")
I don't know if there is a module for this but this can be done pretty easily with some custom code though.
hook_form_alter to add your own validate handler to the node_edit form for the application content type.