fix: use ModelMultipleChoiceField for 'bethere' when hidden (#3894)

The select2-based fields do not behave well on the SubmissionForm when
hidden=True. The ModelMultipleChoiceField is enough for this case.

ietf/secr/sreq/forms.py

@@ -11,6 +11,7 @@ from ietf.group.models import Group
 from ietf.meeting.forms import sessiondetailsformset_factory
 from ietf.meeting.models import ResourceAssociation, Constraint
 from ietf.person.fields import SearchablePersonsField
+from ietf.person.models import Person
 from ietf.utils.html import clean_text_field
 from ietf.utils import log
 
@@ -154,10 +155,17 @@ class SessionForm(forms.Form):
         self.fields["resources"].choices = [(x.pk,x.desc) for x in ResourceAssociation.objects.filter(name__used=True).order_by('name__order') ]
 
         if self.hidden:
+            # replace all the widgets to start...
             for key in list(self.fields.keys()):
                 self.fields[key].widget = forms.HiddenInput()
+            # re-replace a couple special cases
             self.fields['resources'].widget = forms.MultipleHiddenInput()
             self.fields['timeranges'].widget = forms.MultipleHiddenInput()
+            # and entirely replace bethere - no need to support searching if input is hidden
+            self.fields['bethere'] = forms.ModelMultipleChoiceField(
+                widget=forms.MultipleHiddenInput, required=False,
+                queryset=Person.objects.all(),
+            )
 
     def wg_constraint_fields(self):
         """Iterates over wg constraint fields

ietf/secr/sreq/views.py

@@ -289,9 +289,8 @@ def confirm(request, acronym):
         return redirect('ietf.secr.sreq.views.main')
                 
     session_data = form.data.copy()
-    if 'bethere' in session_data:
-        person_id_list = [ id for id in form.data['bethere'].split(',') if id ]
-        session_data['bethere'] = Person.objects.filter(pk__in=person_id_list)
+    # use cleaned_data for the 'bethere' field so we get the Person instances
+    session_data['bethere'] = form.cleaned_data['bethere'] if 'bethere' in form.cleaned_data else []
     if session_data.get('session_time_relation'):
         session_data['session_time_relation_display'] = dict(Constraint.TIME_RELATION_CHOICES)[session_data['session_time_relation']]
     if session_data.get('joint_for_session'):