python - django - How to cross check ModelAdmin and its inlines? -

i have 2 models (modelparent , modelchild) same m2m fields on subject model. modelchild has foreign key on modelparent , modelchild defined inline modelparent on admin page.

### models.py ###   class subject(models.model):     pass    class modelparent(models.model):     subjects_parent = manytomanyfield(subject)    class modelchild(models.model):     parent = foreignkey(modelparent)     subjects_child = manytomanyfield(subject)  ### admin.py ###   class modelchildinline(admin.tabularinline):       model = modelchild    class modelparentadmin(admin.modeladmin):     inlines = [modelchildinline]    admin.site.register(modelparent, modelparentadmin) 

i have 1 important restriction though, modelchild's subjects_child field must not reference subject subject_parent subjects_parent.

so, if select same subject (in subject_parent , subject_child) on admin page both models, how can validate this? if 1 field changes validate against db, if both change (subject_parent , subject_child)? how can validate both forms before saving?

i have inherited new class named modeladminwithinline admin.modeladmin , modified methods add_view(...) , change_view(...) call function is_cross_valid(self, form, formsets), can validate forms together. both functions had:

#... if all_valid(formsets) , form_validated: #... 

changed to:

#... formsets_validated = all_valid(formsets) cross_validated = self.is_cross_valid(form, formsets) if formsets_validated , form_validated , cross_validated: #... 

the new function is_cross_valid(...) defined this:

def is_cross_valid(self, form, formsets):   return true 

so new class should work same modeladmin if don't change is_cross_valid(...) function.

now admin.py looks this:

###admin.py### class modeladminwithinline(admin.modeladmin):   def is_cross_valid(self, form, formsets):     return true    def add_view(self, request, form_url='', extra_context=none):     #modified code    def change_view(self, request, object_id, extra_context=none):     #modified code  class modelchildinline(admin.tabularinline):   model = modelchild  class modelparentadmin(modeladminwithinline):   inlines = [modelchildinline]    def is_cross_valid(self, form, formsets):     #do cross validation on forms     #for example, here particular validation:     valid = true      if hasattr(form, 'cleaned_data'):           subjects_parent = form.cleaned_data.get("subjects_parent")        #you can access forms formsets this:       formset in formsets:         formset_form in formset.forms:           if hasattr(formset_form, 'cleaned_data'):              subjects_child = formset_form.cleaned_data.get("subjects_child")             delete_form = formset_form.cleaned_data.get("delete")              if subjects_child , (delete_form == false):               subject in subjects_child:                 if subject in subjects_parent:                   valid = false                   #from here can still report errors in regular forms:                   if "subjects_child" in formset_form.cleaned_data.keys():                     formset_form._errors["subjects_child"] = errorlist([u"subject %s selected in parent modelparent" % subject])                     del formset_form.cleaned_data["subjects_child"]                   else:                     formset_form._errors["subjects_child"] += errorlist(u"subject %s selected in parent modelparent" % subject])        #return true on success or false otherwise.       return valid  admin.site.register(modelparent, modelparentadmin) 

the solution little bit hackish works :). errors show same regular modelform , modeladmin classes. django 1.2 (which should released shortly) should have model validation, hope problem solved more nicely.