From 79971e14c7e55d9908ffd9ede2aa2e73893be076 Mon Sep 17 00:00:00 2001
From: Jennifer Richards <jennifer@painless-security.com>
Date: Tue, 1 Dec 2020 17:37:09 +0000
Subject: [PATCH] Allow cancellation of individual sessions of multi-session
 interim meeting. Fixes #2959. Commit ready for merge.  - Legacy-Id: 18724

---
 ietf/meeting/ajax.py                          |   8 +-
 ietf/meeting/helpers.py                       |  41 +-
 ietf/meeting/models.py                        |  71 ++-
 ietf/meeting/tests_views.py                   | 584 ++++++++++++++++--
 ietf/meeting/urls.py                          |   1 +
 ietf/meeting/utils.py                         |  44 +-
 ietf/meeting/views.py                         | 103 ++-
 ietf/secr/meetings/views.py                   |   5 +-
 .../meeting/interim_announcement.txt          |   4 +-
 ietf/templates/meeting/interim_info.txt       |   2 +-
 ...> interim_meeting_cancellation_notice.txt} |   0
 .../meeting/interim_request_cancel.html       |   7 +-
 .../meeting/interim_request_details.html      |  29 +-
 .../interim_session_cancellation_notice.txt   |   7 +
 14 files changed, 789 insertions(+), 117 deletions(-)
 rename ietf/templates/meeting/{interim_cancellation_notice.txt => interim_meeting_cancellation_notice.txt} (100%)
 create mode 100644 ietf/templates/meeting/interim_session_cancellation_notice.txt

diff --git a/ietf/meeting/ajax.py b/ietf/meeting/ajax.py
index 44e838deb..d58d7a528 100644
--- a/ietf/meeting/ajax.py
+++ b/ietf/meeting/ajax.py
@@ -11,8 +11,6 @@ from ietf.ietfauth.utils import role_required, has_role
 from ietf.meeting.helpers import get_meeting, get_schedule, schedule_permissions, get_person_by_email, get_schedule_by_name
 from ietf.meeting.models import TimeSlot, Session, Schedule, Room, Constraint, SchedTimeSessAssignment, ResourceAssociation
 from ietf.meeting.views import edit_timeslots, edit_schedule
-from ietf.meeting.utils import only_sessions_that_can_meet
-from ietf.meeting.utils import add_event_info_to_session_qs
 
 import debug                            # pyflakes:ignore
 
@@ -433,11 +431,7 @@ def session_json(request, num, sessionid):
 def sessions_json(request, num):
     meeting = get_meeting(num)
 
-    sessions = add_event_info_to_session_qs(
-        only_sessions_that_can_meet(meeting.session_set),
-        requested_time=True,
-        requested_by=True,
-    )
+    sessions = meeting.session_set.that_can_meet().with_requested_time().with_requested_by()
 
     sess1_dict = [ x.json_dict(request.build_absolute_uri('/')) for x in sessions ]
     return HttpResponse(json.dumps(sess1_dict, sort_keys=True, indent=2),
diff --git a/ietf/meeting/helpers.py b/ietf/meeting/helpers.py
index db766c5ab..d7a3a2a8c 100644
--- a/ietf/meeting/helpers.py
+++ b/ietf/meeting/helpers.py
@@ -467,7 +467,8 @@ def get_announcement_initial(meeting, is_change=False):
         type = 'BOF'
 
     assignments = SchedTimeSessAssignment.objects.filter(
-        schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None]
+        schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None],
+        session__in=meeting.session_set.not_canceled()
     ).order_by('timeslot__time')
 
     initial['subject'] = '{name} ({acronym}) {type} {desc} Meeting: {date}{change}'.format(
@@ -614,7 +615,7 @@ def send_interim_announcement_request(meeting):
               context,
               cc_list)
 
-def send_interim_cancellation_notice(meeting):
+def send_interim_meeting_cancellation_notice(meeting):
     """Sends an email that a scheduled interim meeting has been cancelled."""
     session = meeting.session_set.first()
     group = session.group
@@ -627,9 +628,39 @@ def send_interim_cancellation_notice(meeting):
         date=meeting.date.strftime('%Y-%m-%d'))
     start_time = session.official_timeslotassignment().timeslot.time
     end_time = start_time + session.requested_duration
-    from ietf.meeting.utils import add_event_info_to_session_qs
-    is_multi_day = add_event_info_to_session_qs(meeting.session_set.all()).filter(current_status='sched').count() > 1
-    template = 'meeting/interim_cancellation_notice.txt'
+    is_multi_day = session.meeting.session_set.with_current_status().filter(current_status='sched').count() > 1
+    template = 'meeting/interim_meeting_cancellation_notice.txt'
+    context = locals()
+    send_mail(None,
+              to_email,
+              from_email,
+              subject,
+              template,
+              context,
+              cc=cc_list)
+
+
+def send_interim_session_cancellation_notice(session):
+    """Sends an email that one session of a scheduled interim meeting has been cancelled."""
+    group = session.group
+    start_time = session.official_timeslotassignment().timeslot.time
+    end_time = start_time + session.requested_duration
+    (to_email, cc_list) = gather_address_lists('interim_cancelled',group=group)
+    from_email = settings.INTERIM_ANNOUNCE_FROM_EMAIL_PROGRAM if group.type_id=='program' else settings.INTERIM_ANNOUNCE_FROM_EMAIL_DEFAULT
+
+    if session.name:
+        description = '"%s" session' % session.name
+    else:
+        description = 'interim meeting session'
+
+    subject = '{group} ({acronym}) {type} {description} cancelled (was {date})'.format(
+        group=group.name,
+        acronym=group.acronym,
+        type=group.type.slug.upper(),
+        description=description,
+        date=start_time.date().strftime('%Y-%m-%d'))
+    is_multi_day = session.meeting.session_set.with_current_status().filter(current_status='sched').count() > 1
+    template = 'meeting/interim_session_cancellation_notice.txt'
     context = locals()
     send_mail(None,
               to_email,
diff --git a/ietf/meeting/models.py b/ietf/meeting/models.py
index dd3a976a7..6a49a0590 100644
--- a/ietf/meeting/models.py
+++ b/ietf/meeting/models.py
@@ -17,7 +17,8 @@ import debug                            # pyflakes:ignore
 
 from django.core.validators import MinValueValidator, RegexValidator
 from django.db import models
-from django.db.models import Max
+from django.db.models import Max, Subquery, OuterRef, TextField, Value
+from django.db.models.functions import Coalesce
 from django.conf import settings
 # mostly used by json_dict()
 #from django.template.defaultfilters import slugify, date as date_format, time as time_format
@@ -924,12 +925,78 @@ class SessionPresentation(models.Model):
 constraint_cache_uses = 0
 constraint_cache_initials = 0
 
+class SessionQuerySet(models.QuerySet):
+    def with_current_status(self):
+        """Annotate session with its current status
+        
+        Adds current_status, containing the text representation of the status.
+        """
+        return self.annotate(
+            # coalesce with '' to avoid nulls which give funny
+            # results, e.g. .exclude(current_status='canceled') also
+            # skips rows with null in them
+            current_status=Coalesce(
+                Subquery(
+                    SchedulingEvent.objects.filter(
+                        session=OuterRef('pk')
+                    ).order_by(
+                        '-time', '-id'
+                    ).values('status')[:1]),
+                Value(''), 
+                output_field=TextField()),
+        )
+
+    def with_requested_by(self):
+        """Annotate session with requested_by field
+        
+        Adds requested_by field - pk of the Person who made the request
+        """
+        return self.annotate(
+            requested_by=Subquery(
+                SchedulingEvent.objects.filter(
+                    session=OuterRef('pk')
+                ).order_by(
+                    'time', 'id'
+                ).values('by')[:1]),
+        )
+
+    def with_requested_time(self):
+        """Annotate session with requested_time field"""
+        return self.annotate(
+            requested_time=Subquery(
+                SchedulingEvent.objects.filter(
+                    session=OuterRef('pk')
+                ).order_by(
+                    'time', 'id'
+                ).values('time')[:1]),
+        )
+
+    def not_canceled(self):
+        """Queryset containing all sessions not canceled
+                
+        Results annotated with current_status
+        """
+        return self.with_current_status().exclude(current_status__in=Session.CANCELED_STATUSES)
+
+    def that_can_meet(self):
+        """Queryset containing sessions that can meet
+        
+        Results annotated with current_status
+        """
+        return self.with_current_status().exclude(
+            current_status__in=['notmeet', 'disappr', 'deleted', 'apprw']
+        ).filter(
+            type__slug='regular'
+        )
+
+
 class Session(models.Model):
     """Session records that a group should have a session on the
     meeting (time and location is stored in a TimeSlot) - if multiple
     timeslots are needed, multiple sessions will have to be created.
     Training sessions and similar are modeled by filling in a
     responsible group (e.g. Edu team) and filling in the name."""
+    objects = SessionQuerySet.as_manager()  # sets default query manager
     meeting = ForeignKey(Meeting)
     name = models.CharField(blank=True, max_length=255, help_text="Name of session, in case the session has a purpose rather than just being a group meeting.")
     short = models.CharField(blank=True, max_length=32, help_text="Short version of 'name' above, for use in filenames.")
@@ -951,6 +1018,8 @@ class Session(models.Model):
 
     unique_constraints_dict = None
 
+    CANCELED_STATUSES = ['canceled', 'canceledpa']
+    
     # Should work on how materials are captured so that deleted things are no longer associated with the session
     # (We can keep the information about something being added to and removed from a session in the document's history)
     def get_material(self, material_type, only_one):
diff --git a/ietf/meeting/tests_views.py b/ietf/meeting/tests_views.py
index d965106da..a3e9e0a91 100644
--- a/ietf/meeting/tests_views.py
+++ b/ietf/meeting/tests_views.py
@@ -33,7 +33,7 @@ from ietf.group.utils import can_manage_group
 from ietf.person.models import Person
 from ietf.meeting.helpers import can_approve_interim_request, can_view_interim_request
 from ietf.meeting.helpers import send_interim_approval_request
-from ietf.meeting.helpers import send_interim_cancellation_notice
+from ietf.meeting.helpers import send_interim_meeting_cancellation_notice, send_interim_session_cancellation_notice
 from ietf.meeting.helpers import send_interim_minutes_reminder, populate_important_dates, update_important_dates
 from ietf.meeting.models import Session, TimeSlot, Meeting, SchedTimeSessAssignment, Schedule, SessionPresentation, SlideSubmission, SchedulingEvent, Room, Constraint, ConstraintName
 from ietf.meeting.test_data import make_meeting_test_data, make_interim_meeting, make_interim_test_data
@@ -1934,67 +1934,288 @@ class InterimTests(TestCase):
 
     # test_interim_announce subsumed by test_appears_on_announce
 
-    def test_interim_skip_announcement(self):
+    def do_interim_skip_announcement_test(self, base_session=False, extra_session=False, canceled_session=False):
         make_meeting_test_data()
         group = Group.objects.get(acronym='irg')
         date = datetime.date.today() + datetime.timedelta(days=30)
         meeting = make_interim_meeting(group=group, date=date, status='scheda')
+        session = meeting.session_set.first()
+        if base_session:
+            base_session = SessionFactory(meeting=meeting, status_id='apprw', add_to_schedule=False)
+            meeting.schedule.base = Schedule.objects.create(
+                meeting=meeting, owner=PersonFactory(), name="base", visible=True, public=True
+            )
+            SchedTimeSessAssignment.objects.create(
+                timeslot=TimeSlotFactory.create(meeting=meeting),
+                session=base_session,
+                schedule=meeting.schedule.base,
+            )
+            meeting.schedule.save()
+        if extra_session:
+            extra_session = SessionFactory(meeting=meeting, status_id='scheda')
+        if canceled_session:
+            canceled_session = SessionFactory(meeting=meeting, status_id='canceledpa')
         url = urlreverse("ietf.meeting.views.interim_skip_announcement", kwargs={'number': meeting.number})
         login_testing_unauthorized(self, "secretary", url)
         r = self.client.get(url)
         self.assertEqual(r.status_code, 200)
-        
+
         # check post
         len_before = len(outbox)
         r = self.client.post(url)
         self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_announce'))
-        self.assertEqual(add_event_info_to_session_qs(meeting.session_set).first().current_status, 'sched')
+        meeting_sessions = meeting.session_set.with_current_status()
+        self.assertEqual(meeting_sessions.get(pk=session.pk).current_status, 'sched')
+        if base_session:
+            self.assertEqual(meeting_sessions.get(pk=base_session.pk).current_status, 'sched')            
+        if extra_session:
+            self.assertEqual(meeting_sessions.get(pk=extra_session.pk).current_status, 'sched')
+        if canceled_session:
+            self.assertEqual(meeting_sessions.get(pk=canceled_session.pk).current_status, 'canceledpa')
         self.assertEqual(len(outbox), len_before)
-        
-    def test_interim_send_announcement(self):
+
+    def test_interim_skip_announcement(self):
+        """skip_announcement should move single session to sched state"""
+        self.do_interim_skip_announcement_test()
+
+    def test_interim_skip_announcement_with_base_sched(self):
+        """skip_announcement should move single session to sched state"""
+        self.do_interim_skip_announcement_test(base_session=True)
+
+    def test_interim_skip_announcement_with_extra_session(self):
+        """skip_announcement should move multiple sessions to sched state"""
+        self.do_interim_skip_announcement_test(extra_session=True)
+
+    def test_interim_skip_announcement_with_extra_session_and_base_sched(self):
+        """skip_announcement should move multiple sessions to sched state"""
+        self.do_interim_skip_announcement_test(extra_session=True, base_session=True)
+
+    def test_interim_skip_announcement_with_canceled_session(self):
+        """skip_announcement should not schedule a canceled session"""
+        self.do_interim_skip_announcement_test(canceled_session=True)
+
+    def test_interim_skip_announcement_with_canceled_session_and_base_sched(self):
+        """skip_announcement should not schedule a canceled session"""
+        self.do_interim_skip_announcement_test(canceled_session=True, base_session=True)
+
+    def test_interim_skip_announcement_with_extra_and_canceled_sessions(self):
+        """skip_announcement should schedule multiple sessions and leave canceled session alone"""
+        self.do_interim_skip_announcement_test(extra_session=True, canceled_session=True)
+
+    def test_interim_skip_announcement_with_extra_and_canceled_sessions_and_base_sched(self):
+        """skip_announcement should schedule multiple sessions and leave canceled session alone"""
+        self.do_interim_skip_announcement_test(extra_session=True, canceled_session=True, base_session=True)
+
+    def do_interim_send_announcement_test(self, base_session=False, extra_session=False, canceled_session=False):
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw').first()
+        meeting = session.meeting
         meeting.time_zone = 'America/Los_Angeles'
         meeting.save()
 
+        if base_session:
+            base_session = SessionFactory(meeting=meeting, status_id='apprw', add_to_schedule=False)
+            meeting.schedule.base = Schedule.objects.create(
+                meeting=meeting, owner=PersonFactory(), name="base", visible=True, public=True
+            )
+            SchedTimeSessAssignment.objects.create(
+                timeslot=TimeSlotFactory.create(meeting=meeting),
+                session=base_session,
+                schedule=meeting.schedule.base,
+            )
+            meeting.schedule.save()
+        if extra_session:
+            extra_session = SessionFactory(meeting=meeting, status_id='apprw')
+        if canceled_session:
+            canceled_session = SessionFactory(meeting=meeting, status_id='canceledpa')
+
         url = urlreverse("ietf.meeting.views.interim_send_announcement", kwargs={'number': meeting.number})
         login_testing_unauthorized(self, "secretary", url)
         r = self.client.get(url)
         self.assertEqual(r.status_code, 200)
         initial = r.context['form'].initial
+
         # send announcement
         len_before = len(outbox)
         r = self.client.post(url, initial)
         self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_announce'))
         self.assertEqual(len(outbox), len_before + 1)
-        self.assertIn('WG Virtual Meeting', outbox[-1]['Subject'])
-        self.assertIn('09:00 to 09:20 America/Los_Angeles', get_payload_text(outbox[-1]))
+        announcement_msg = outbox[-1]
+        announcement_text = get_payload_text(announcement_msg)
+        self.assertIn('WG Virtual Meeting', announcement_msg['Subject'])
+        self.assertIn('09:00 to 09:20 America/Los_Angeles', announcement_text)
+        for sess in [session, base_session, extra_session]:
+            if sess:
+                timeslot = sess.official_timeslotassignment().timeslot
+                self.assertIn(timeslot.time.strftime('%Y-%m-%d'), announcement_text)
+                self.assertIn(
+                    '(%s to %s UTC)' % (
+                        timeslot.utc_start_time().strftime('%H:%M'),timeslot.utc_end_time().strftime('%H:%M')
+                    ), announcement_text)
+        # Count number of sessions listed
+        if base_session and extra_session:
+            expected_session_matches = 3
+        elif base_session or extra_session:
+            expected_session_matches = 2
+        else:
+            expected_session_matches = 0  # no session list when only one session
+        session_matches = re.findall(r'Session \d+:', announcement_text)
+        self.assertEqual(len(session_matches), expected_session_matches) 
 
-        timeslot = meeting.session_set.first().official_timeslotassignment().timeslot
-        self.assertIn('(%s to %s UTC)'%(timeslot.utc_start_time().strftime('%H:%M'),timeslot.utc_end_time().strftime('%H:%M')), get_payload_text(outbox[-1]))
+        meeting_sessions = meeting.session_set.with_current_status()
+        self.assertEqual(meeting_sessions.get(pk=session.pk).current_status, 'sched')
+        if base_session:
+            self.assertEqual(meeting_sessions.get(pk=base_session.pk).current_status, 'sched')
+        if extra_session:
+            self.assertEqual(meeting_sessions.get(pk=extra_session.pk).current_status, 'sched')
+        if canceled_session:
+            self.assertEqual(meeting_sessions.get(pk=canceled_session.pk).current_status, 'canceledpa')
 
-    def test_interim_approve_by_ad(self):
+    def test_interim_send_announcement(self):
+        self.do_interim_send_announcement_test()
+
+    def test_interim_send_announcement_with_base_sched(self):
+        self.do_interim_send_announcement_test(base_session=True)
+
+    def test_interim_send_announcement_with_extra_session(self):
+        self.do_interim_send_announcement_test(extra_session=True)
+
+    def test_interim_send_announcement_with_extra_session_and_base_sched(self):
+        self.do_interim_send_announcement_test(extra_session=True, base_session=True)
+
+    def test_interim_send_announcement_with_canceled_session(self):
+        self.do_interim_send_announcement_test(canceled_session=True)
+
+    def test_interim_send_announcement_with_canceled_session_and_base_sched(self):
+        self.do_interim_send_announcement_test(canceled_session=True, base_session=True)
+
+    def test_interim_send_announcement_with_extra_and_canceled_sessions(self):
+        self.do_interim_send_announcement_test(extra_session=True, canceled_session=True)
+
+    def test_interim_send_announcement_with_extra_and_canceled_sessions_and_base_sched(self):
+        self.do_interim_send_announcement_test(extra_session=True, canceled_session=True, base_session=True)
+
+    def do_interim_approve_by_ad_test(self, base_session=False, extra_session=False, canceled_session=False):
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw').first()
+        meeting = session.meeting
+
+        if base_session:
+            base_session = SessionFactory(meeting=meeting, status_id='apprw', add_to_schedule=False)
+            meeting.schedule.base = Schedule.objects.create(
+                meeting=meeting, owner=PersonFactory(), name="base", visible=True, public=True
+            )
+            SchedTimeSessAssignment.objects.create(
+                timeslot=TimeSlotFactory.create(meeting=meeting),
+                session=base_session,
+                schedule=meeting.schedule.base,
+            )
+            meeting.schedule.save()
+        if extra_session:
+            extra_session = SessionFactory(meeting=meeting, status_id='apprw')
+        if canceled_session:
+            canceled_session = SessionFactory(meeting=meeting, status_id='canceledpa')
+
         url = urlreverse('ietf.meeting.views.interim_request_details', kwargs={'number': meeting.number})
         length_before = len(outbox)
         login_testing_unauthorized(self, "ad", url)
         r = self.client.post(url, {'approve': 'approve'})
         self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_pending'))
-        for session in add_event_info_to_session_qs(meeting.session_set.all()):
-            self.assertEqual(session.current_status, 'scheda')
+
+        for sess in [session, base_session, extra_session]:
+            if sess:
+                self.assertEqual(Session.objects.with_current_status().get(pk=sess.pk).current_status,
+                                 'scheda')
+        if canceled_session:
+            self.assertEqual(Session.objects.with_current_status().get(pk=canceled_session.pk).current_status,
+                             'canceledpa')
         self.assertEqual(len(outbox), length_before + 1)
         self.assertIn('ready for announcement', outbox[-1]['Subject'])
 
-    def test_interim_approve_by_secretariat(self):
+    def test_interim_approve_by_ad(self):
+        self.do_interim_approve_by_ad_test()
+
+    def test_interim_approve_by_ad_with_base_sched(self):
+        self.do_interim_approve_by_ad_test(base_session=True)
+
+    def test_interim_approve_by_ad_with_extra_session(self):
+        self.do_interim_approve_by_ad_test(extra_session=True)
+
+    def test_interim_approve_by_ad_with_extra_session_and_base_sched(self):
+        self.do_interim_approve_by_ad_test(extra_session=True, base_session=True)
+
+    def test_interim_approve_by_ad_with_canceled_session(self):
+        self.do_interim_approve_by_ad_test(canceled_session=True)
+
+    def test_interim_approve_by_ad_with_canceled_session_and_base_sched(self):
+        self.do_interim_approve_by_ad_test(canceled_session=True, base_session=True)
+
+    def test_interim_approve_by_ad_with_extra_and_canceled_sessions(self):
+        self.do_interim_approve_by_ad_test(extra_session=True, canceled_session=True)
+
+    def test_interim_approve_by_ad_with_extra_and_canceled_sessions_and_base_sched(self):
+        self.do_interim_approve_by_ad_test(extra_session=True, canceled_session=True, base_session=True)
+
+    def do_interim_approve_by_secretariat_test(self, base_session=False, extra_session=False, canceled_session=False):
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw').first()
+        meeting = session.meeting
+        if base_session:
+            base_session = SessionFactory(meeting=meeting, status_id='apprw', add_to_schedule=False)
+            meeting.schedule.base = Schedule.objects.create(
+                meeting=meeting, owner=PersonFactory(), name="base", visible=True, public=True
+            )
+            SchedTimeSessAssignment.objects.create(
+                timeslot=TimeSlotFactory.create(meeting=meeting),
+                session=base_session,
+                schedule=meeting.schedule.base,
+            )
+            meeting.schedule.save()
+        if extra_session:
+            extra_session = SessionFactory(meeting=meeting, status_id='apprw')
+        if canceled_session:
+            canceled_session = SessionFactory(meeting=meeting, status_id='canceledpa')
+
         url = urlreverse('ietf.meeting.views.interim_request_details', kwargs={'number': meeting.number})
+        length_before = len(outbox)
         login_testing_unauthorized(self, "secretary", url)
         r = self.client.post(url, {'approve': 'approve'})
         self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_send_announcement', kwargs={'number': meeting.number}))
-        for session in add_event_info_to_session_qs(meeting.session_set.all()):
-            self.assertEqual(session.current_status, 'scheda')
+        for sess in [session, base_session, extra_session]:
+            if sess:
+                self.assertEqual(Session.objects.with_current_status().get(pk=sess.pk).current_status,
+                                 'scheda')
+        if canceled_session:
+            self.assertEqual(Session.objects.with_current_status().get(pk=canceled_session.pk).current_status,
+                             'canceledpa')
+        self.assertEqual(len(outbox), length_before)
+
+    def test_interim_approve_by_secretariat(self):
+        self.do_interim_approve_by_secretariat_test()
+
+    def test_interim_approve_by_secretariat_with_base_sched(self):
+        self.do_interim_approve_by_secretariat_test(base_session=True)
+
+    def test_interim_approve_by_secretariat_with_extra_session(self):
+        self.do_interim_approve_by_secretariat_test(extra_session=True)
+
+    def test_interim_approve_by_secretariat_with_extra_session_and_base_sched(self):
+        self.do_interim_approve_by_secretariat_test(extra_session=True, base_session=True)
+
+    def test_interim_approve_by_secretariat_with_canceled_session(self):
+        self.do_interim_approve_by_secretariat_test(canceled_session=True)
+
+    def test_interim_approve_by_secretariat_with_canceled_session_and_base_sched(self):
+        self.do_interim_approve_by_secretariat_test(canceled_session=True, base_session=True)
+
+    def test_interim_approve_by_secretariat_with_extra_and_canceled_sessions(self):
+        self.do_interim_approve_by_secretariat_test(extra_session=True, canceled_session=True)
+
+    def test_interim_approve_by_secretariat_with_extra_and_canceled_sessions_and_base_sched(self):
+        self.do_interim_approve_by_secretariat_test(extra_session=True, canceled_session=True, base_session=True)
 
     def test_past(self):
         today = datetime.date.today()
@@ -2387,6 +2608,10 @@ class InterimTests(TestCase):
         meeting_count_before = Meeting.objects.filter(type='interim').count()
         date = datetime.date.today() + datetime.timedelta(days=30)
         date2 = date + datetime.timedelta(days=1)
+        # ensure dates are in the same year
+        if date.year != date2.year:
+            date += datetime.timedelta(days=1)
+            date2 += datetime.timedelta(days=1)
         time = datetime.datetime.now().time().replace(microsecond=0,second=0)
         dt = datetime.datetime.combine(date, time)
         dt2 = datetime.datetime.combine(date2, time)
@@ -2536,7 +2761,8 @@ class InterimTests(TestCase):
 
     def test_interim_request_details(self):
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
+        meeting = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw').first().meeting
         url = urlreverse('ietf.meeting.views.interim_request_details',kwargs={'number':meeting.number})
         login_testing_unauthorized(self,"secretary",url)
         r = self.client.get(url)
@@ -2568,51 +2794,317 @@ class InterimTests(TestCase):
         q = PyQuery(r.content)
         self.assertEqual(len(q("a.btn:contains('Announce')")),2)
 
-    def test_interim_request_disapprove(self):
+    def test_interim_request_details_cancel(self):
+        """Test access to cancel meeting / session features"""
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
+        mars_sessions = Session.objects.with_current_status(
+        ).filter(
+            meeting__type='interim',
+            group__acronym='mars',
+        )
+        meeting_apprw = mars_sessions.filter(current_status='apprw').first().meeting
+        meeting_sched = mars_sessions.filter(current_status='sched').first().meeting
+        # All these roles should have access to cancel the request
+        usernames_and_passwords = (
+            ('marschairman', 'marschairman+password'),
+            ('secretary', 'secretary+password')
+        )
+        
+        # Start with one session - there should not be any cancel session buttons
+        for meeting in (meeting_apprw, meeting_sched):
+            url = urlreverse('ietf.meeting.views.interim_request_details', 
+                             kwargs={'number': meeting.number})
+
+            for username, password in usernames_and_passwords:
+                self.client.login(username=username, password=password)
+                r = self.client.get(url)
+                self.assertEqual(r.status_code, 200)
+                q = PyQuery(r.content)
+
+                cancel_meeting_btns = q("a.btn:contains('Cancel Meeting')")
+                self.assertEqual(len(cancel_meeting_btns), 1,
+                                 'Should be exactly one cancel meeting button for user %s' % username)
+                self.assertEqual(cancel_meeting_btns.eq(0).attr('href'),
+                                 urlreverse('ietf.meeting.views.interim_request_cancel',
+                                            kwargs={'number': meeting.number}),
+                                 'Cancel meeting points to wrong URL')
+
+                self.assertEqual(len(q("a.btn:contains('Cancel Session')")), 0,
+                                 'Should be no cancel session buttons for user %s' % username)
+
+        # Add a second session
+        SessionFactory(meeting=meeting_apprw, status_id='apprw')
+        SessionFactory(meeting=meeting_sched, status_id='sched')
+
+        for meeting in (meeting_apprw, meeting_sched):
+            url = urlreverse('ietf.meeting.views.interim_request_details',
+                             kwargs={'number': meeting.number})
+
+            for username, password in usernames_and_passwords:
+                self.client.login(username=username, password=password)
+                r = self.client.get(url)
+                self.assertEqual(r.status_code, 200)
+                q = PyQuery(r.content)
+                cancel_meeting_btns = q("a.btn:contains('Cancel Meeting')")
+                self.assertEqual(len(cancel_meeting_btns), 1,
+                                 'Should be exactly one cancel meeting button for user %s' % username)
+                self.assertEqual(cancel_meeting_btns.eq(0).attr('href'),
+                                 urlreverse('ietf.meeting.views.interim_request_cancel',
+                                            kwargs={'number': meeting.number}),
+                                 'Cancel meeting button points to wrong URL')
+
+                cancel_session_btns = q("a.btn:contains('Cancel Session')")
+                self.assertEqual(len(cancel_session_btns), 2,
+                                 'Should be two cancel session buttons for user %s' % username)
+                hrefs = [btn.attr('href') for btn in cancel_session_btns.items()]
+                for index, session in enumerate(meeting.session_set.all()):
+                    self.assertIn(urlreverse('ietf.meeting.views.interim_request_session_cancel',
+                                             kwargs={'sessionid': session.pk}),
+                                  hrefs,
+                                  'Session missing a link to its cancel URL')
+
+    def test_interim_request_details_status(self):
+        """Test statuses on the interim request details page"""
+        make_interim_test_data()
+        some_person = PersonFactory()
+        self.client.login(username='marschairman', password='marschairman+password')
+        # These are the first sessions for each meeting - hang on to them
+        sessions = list(
+            Session.objects.with_current_status().filter(meeting__type='interim', group__acronym='mars')
+        )
+
+        # Hack: change the name for the 'canceled' session status so we can tell it apart
+        # from the 'canceledpa' session status more easily
+        canceled_status = SessionStatusName.objects.get(slug='canceled')
+        canceled_status.name = 'This is cancelled'
+        canceled_status.save()
+        canceledpa_status = SessionStatusName.objects.get(slug='canceledpa')
+        notmeet_status = SessionStatusName.objects.get(slug='notmeet')
+
+        # Simplest case - single session for each meeting
+        for session in [Session.objects.with_current_status().get(pk=s.pk) for s in sessions]:
+            url = urlreverse('ietf.meeting.views.interim_request_details',
+                             kwargs={'number': session.meeting.number})
+            r = self.client.get(url)
+            self.assertEqual(r.status_code, 200)
+            q = PyQuery(r.content)
+            status = SessionStatusName.objects.get(slug=session.current_status)
+            self.assertEqual(
+                len(q("dd:contains('%s')" % status.name)),
+                1  # once - for the meeting status, no session status shown when only one session
+            )
+
+        # Now add a second session with a different status - it should not change meeting status
+        for session in [Session.objects.with_current_status().get(pk=s.pk) for s in sessions]:
+            SessionFactory(meeting=session.meeting, status_id=notmeet_status.pk)
+            url = urlreverse('ietf.meeting.views.interim_request_details',
+                             kwargs={'number': session.meeting.number})
+            r = self.client.get(url)
+            self.assertEqual(r.status_code, 200)
+            q = PyQuery(r.content)
+            status = SessionStatusName.objects.get(slug=session.current_status)
+            self.assertEqual(
+                len(q("dd:contains('%s')" % status.name)),
+                2  # twice - once as the meeting status, once as the session status
+            )
+            self.assertEqual(
+                len(q("dd:contains('%s')" % notmeet_status.name)),
+                1  # only for the session status
+            )
+
+        # Now cancel the first session - second meeting status should be shown for meeting
+        for session in [Session.objects.with_current_status().get(pk=s.pk) for s in sessions]:
+            # Use 'canceledpa' here and 'canceled' later
+            SchedulingEvent.objects.create(session=session,
+                                           status=canceledpa_status,
+                                           by=some_person)
+            url = urlreverse('ietf.meeting.views.interim_request_details',
+                             kwargs={'number': session.meeting.number})
+            r = self.client.get(url)
+            self.assertEqual(r.status_code, 200)
+            q = PyQuery(r.content)
+            self.assertEqual(
+                len(q("dd:contains('%s')" % canceledpa_status.name)),
+                1  # only for the session status
+            )
+            self.assertEqual(
+                len(q("dd:contains('%s')" % notmeet_status.name)),
+                2  # twice - once as the meeting status, once as the session status
+            )
+
+        # Now cancel the second session - first meeting status should be shown for meeting again
+        for session in [Session.objects.with_current_status().get(pk=s.pk) for s in sessions]:
+            second_session = session.meeting.session_set.exclude(pk=session.pk).first()
+            # use canceled so we can differentiate between the first and second session statuses
+            SchedulingEvent.objects.create(session=second_session,
+                                           status=canceled_status,
+                                           by=some_person)
+            url = urlreverse('ietf.meeting.views.interim_request_details',
+                             kwargs={'number': session.meeting.number})
+            r = self.client.get(url)
+            self.assertEqual(r.status_code, 200)
+            q = PyQuery(r.content)
+            self.assertEqual(
+                len(q("dd:contains('%s')" % canceledpa_status.name)),
+                2  # twice - once as the meeting status, once as the session status
+            )
+            self.assertEqual(
+                len(q("dd:contains('%s')" % canceled_status.name)),
+                1  # only as the session status
+            )
+
+    def do_interim_request_disapprove_test(self, extra_session=False, canceled_session=False):
+        make_interim_test_data()
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw').first()
+        meeting = session.meeting
+        if extra_session:
+            extra_session = SessionFactory(meeting=meeting, status_id='apprw')
+        if canceled_session:
+            canceled_session = SessionFactory(meeting=meeting, status_id='canceledpa')
+
         url = urlreverse('ietf.meeting.views.interim_request_details',kwargs={'number':meeting.number})
         login_testing_unauthorized(self,"secretary",url)
         r = self.client.post(url,{'disapprove':'Disapprove'})
         self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_pending'))
-        for session in add_event_info_to_session_qs(meeting.session_set.all()):
-            self.assertEqual(session.current_status,'disappr')
+        for sess in [session, extra_session]:
+            if sess:
+                self.assertEqual(Session.objects.with_current_status().get(pk=sess.pk).current_status,
+                                 'disappr')
+        if canceled_session:
+            self.assertEqual(Session.objects.with_current_status().get(pk=canceled_session.pk).current_status,
+                             'canceledpa')
+
+    def test_interim_request_disapprove(self):
+        self.do_interim_request_disapprove_test()
+
+    def test_interim_request_disapprove_with_extra_session(self):
+        self.do_interim_request_disapprove_test(extra_session=True)
+
+    def test_interim_request_disapprove_with_canceled_session(self):
+        self.do_interim_request_disapprove_test(canceled_session=True)
+
+    def test_interim_request_disapprove_with_extra_and_canceled_sessions(self):
+        self.do_interim_request_disapprove_test(extra_session=True, canceled_session=True)
 
     def test_interim_request_cancel(self):
+        """Test that interim request cancel function works
+        
+        Does not test that UI buttons are present, that is handled elsewhere.
+        """
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='apprw').first().meeting
-        url = urlreverse('ietf.meeting.views.interim_request_details', kwargs={'number': meeting.number})
-        self.client.login(username="marschairman", password="marschairman+password")
-        r = self.client.get(url)
-        self.assertEqual(r.status_code, 200)
-        q = PyQuery(r.content)
-        self.assertEqual(len(q("a.btn:contains('Cancel')")), 1)
+        meeting = Session.objects.with_current_status(
+        ).filter(
+            meeting__type='interim',
+            group__acronym='mars',
+            current_status='apprw',
+        ).first().meeting
+
         # ensure fail unauthorized
         url = urlreverse('ietf.meeting.views.interim_request_cancel', kwargs={'number': meeting.number})
         comments = 'Bob cannot make it'
         self.client.login(username="ameschairman", password="ameschairman+password")
         r = self.client.post(url, {'comments': comments})
         self.assertEqual(r.status_code, 403)
+
         # test cancelling before announcement
         self.client.login(username="marschairman", password="marschairman+password")
         length_before = len(outbox)
         r = self.client.post(url, {'comments': comments})
         self.assertRedirects(r, urlreverse('ietf.meeting.views.upcoming'))
-        for session in add_event_info_to_session_qs(meeting.session_set.all()):
+        for session in meeting.session_set.with_current_status():
             self.assertEqual(session.current_status,'canceledpa')
             self.assertEqual(session.agenda_note, comments)
         self.assertEqual(len(outbox), length_before)     # no email notice
+
         # test cancelling after announcement
         meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='sched').first().meeting
         url = urlreverse('ietf.meeting.views.interim_request_cancel', kwargs={'number': meeting.number})
         r = self.client.post(url, {'comments': comments})
         self.assertRedirects(r, urlreverse('ietf.meeting.views.upcoming'))
-        for session in add_event_info_to_session_qs(meeting.session_set.all()):
+        for session in meeting.session_set.with_current_status():
             self.assertEqual(session.current_status,'canceled')
             self.assertEqual(session.agenda_note, comments)
         self.assertEqual(len(outbox), length_before + 1)
         self.assertIn('Interim Meeting Cancelled', outbox[-1]['Subject'])
 
+    def test_interim_request_session_cancel(self):
+        """Test that interim meeting session cancellation functions
+
+        Does not test that UI buttons are present, that is handled elsewhere.
+        """
+        make_interim_test_data()
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='apprw',).first()
+        meeting = session.meeting
+        comments = 'Bob cannot make it'
+        
+        # Should not be able to cancel when there is only one session
+        self.client.login(username="marschairman", password="marschairman+password")
+        url = urlreverse('ietf.meeting.views.interim_request_session_cancel', kwargs={'sessionid': session.pk})
+        r = self.client.post(url, {'comments': comments})
+        self.assertEqual(r.status_code, 409)
+
+        # Add a second session
+        SessionFactory(meeting=meeting, status_id='apprw')
+
+        # ensure fail unauthorized
+        url = urlreverse('ietf.meeting.views.interim_request_session_cancel', kwargs={'sessionid': session.pk})
+        self.client.login(username="ameschairman", password="ameschairman+password")
+        r = self.client.post(url, {'comments': comments})
+        self.assertEqual(r.status_code, 403)
+        
+        # test cancelling before announcement
+        self.client.login(username="marschairman", password="marschairman+password")
+        length_before = len(outbox)
+        canceled_count_before = meeting.session_set.with_current_status().filter(
+            current_status__in=['canceled', 'canceledpa']).count()
+        r = self.client.post(url, {'comments': comments})
+        self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_request_details', 
+                                           kwargs={'number': meeting.number}))
+        # This session should be canceled...
+        sessions = meeting.session_set.with_current_status()
+        session = sessions.filter(id=session.pk).first()  # reload our session info
+        self.assertEqual(session.current_status, 'canceledpa')
+        self.assertEqual(session.agenda_note, comments)
+        # But others should not - count should have changed by only 1
+        self.assertEqual(
+            sessions.filter(current_status__in=['canceled', 'canceledpa']).count(),
+            canceled_count_before + 1
+        )
+        self.assertEqual(len(outbox), length_before)     # no email notice
+
+        # test cancelling after announcement
+        session = Session.objects.with_current_status().filter(
+            meeting__type='interim', group__acronym='mars', current_status='sched').first()
+        meeting = session.meeting
+        
+        # Try to cancel when there's only one session in the meeting
+        url = urlreverse('ietf.meeting.views.interim_request_session_cancel', kwargs={'sessionid': session.pk})
+        r = self.client.post(url, {'comments': comments})
+        self.assertEqual(r.status_code, 409)
+
+        # Add another session
+        SessionFactory(meeting=meeting, status_id='sched')  # two sessions so canceling a session makes sense
+
+        canceled_count_before = meeting.session_set.with_current_status().filter(
+            current_status__in=['canceled', 'canceledpa']).count()
+        r = self.client.post(url, {'comments': comments})
+        self.assertRedirects(r, urlreverse('ietf.meeting.views.interim_request_details',
+                                           kwargs={'number': meeting.number}))
+        # This session should be canceled...
+        sessions = meeting.session_set.with_current_status()
+        session = sessions.filter(id=session.pk).first()  # reload our session info
+        self.assertEqual(session.current_status, 'canceled')
+        self.assertEqual(session.agenda_note, comments)
+        # But others should not - count should have changed by only 1
+        self.assertEqual(
+            sessions.filter(current_status__in=['canceled', 'canceledpa']).count(),
+            canceled_count_before + 1
+        )
+        self.assertEqual(len(outbox), length_before + 1)     # email notice sent
+        self.assertIn('session cancelled', outbox[-1]['Subject'])
+
     def test_interim_request_edit_no_notice(self):
         '''Edit a request.  No notice should go out if it hasn't been announced yet'''
         make_interim_test_data()
@@ -2716,14 +3208,32 @@ class InterimTests(TestCase):
         self.assertEqual(len(outbox),length_before+1)
         self.assertIn('New Interim Meeting Request', outbox[-1]['Subject'])
 
-    def test_send_interim_cancellation_notice(self):
+    def test_send_interim_meeting_cancellation_notice(self):
         make_interim_test_data()
-        meeting = add_event_info_to_session_qs(Session.objects.filter(meeting__type='interim', group__acronym='mars')).filter(current_status='sched').first().meeting
+        meeting = Session.objects.with_current_status(
+        ).filter(
+            meeting__type='interim',
+            group__acronym='mars',
+            current_status='sched',
+        ).first().meeting
         length_before = len(outbox)
-        send_interim_cancellation_notice(meeting=meeting)
-        self.assertEqual(len(outbox),length_before+1)
+        send_interim_meeting_cancellation_notice(meeting)
+        self.assertEqual(len(outbox),length_before + 1)
         self.assertIn('Interim Meeting Cancelled', outbox[-1]['Subject'])
 
+    def test_send_interim_session_cancellation_notice(self):
+        make_interim_test_data()
+        session = Session.objects.with_current_status(
+        ).filter(
+            meeting__type='interim',
+            group__acronym='mars',
+            current_status='sched',
+        ).first()
+        length_before = len(outbox)
+        send_interim_session_cancellation_notice(session)
+        self.assertEqual(len(outbox), length_before + 1)
+        self.assertIn('session cancelled', outbox[-1]['Subject'])
+
     def test_send_interim_minutes_reminder(self):
         make_meeting_test_data()
         group = Group.objects.get(acronym='mars')
diff --git a/ietf/meeting/urls.py b/ietf/meeting/urls.py
index c914a5ceb..a8c627dc9 100644
--- a/ietf/meeting/urls.py
+++ b/ietf/meeting/urls.py
@@ -118,6 +118,7 @@ urlpatterns = [
     url(r'^interim/request/(?P<number>[A-Za-z0-9._+-]+)/?$', views.interim_request_details),
     url(r'^interim/request/(?P<number>[A-Za-z0-9._+-]+)/edit/?$', views.interim_request_edit),
     url(r'^interim/request/(?P<number>[A-Za-z0-9._+-]+)/cancel/?$', views.interim_request_cancel),
+    url(r'^interim/session/(?P<sessionid>[A-Za-z0-9._+-]+)/cancel/?$', views.interim_request_session_cancel),
     url(r'^interim/pending/?$', views.interim_pending),
     url(r'^requests.html$', RedirectView.as_view(url='/meeting/requests', permanent=True)),
     url(r'^past/?$', views.past),
diff --git a/ietf/meeting/utils.py b/ietf/meeting/utils.py
index 27567541b..0ff7115ba 100644
--- a/ietf/meeting/utils.py
+++ b/ietf/meeting/utils.py
@@ -12,7 +12,6 @@ from urllib.error import HTTPError
 
 from django.conf import settings
 from django.template.loader import render_to_string
-from django.db.models.expressions import Subquery, OuterRef
 from django.utils.html import format_html
 from django.utils.safestring import mark_safe
 
@@ -48,7 +47,7 @@ def session_requested_by(session):
     return None
 
 def current_session_status(session):
-    last_event = SchedulingEvent.objects.filter(session=session).order_by('-time', '-id').first()
+    last_event = SchedulingEvent.objects.filter(session=session).select_related('status').order_by('-time', '-id').first()
     if last_event:
         return last_event.status
 
@@ -220,34 +219,18 @@ def condition_slide_order(session):
 def add_event_info_to_session_qs(qs, current_status=True, requested_by=False, requested_time=False):
     """Take a session queryset and add attributes computed from the
     scheduling events. A queryset is returned and the added attributes
-    can be further filtered on."""
-    from django.db.models import TextField, Value
-    from django.db.models.functions import Coalesce
+    can be further filtered on.
+    
+    Treat this method as deprecated. Use the SessionQuerySet methods directly, chaining if needed.
+    """
     if current_status:
-        qs = qs.annotate(
-            # coalesce with '' to avoid nulls which give funny
-            # results, e.g. .exclude(current_status='canceled') also
-            # skips rows with null in them
-            current_status=Coalesce(Subquery(SchedulingEvent.objects.filter(session=OuterRef('pk')).order_by('-time', '-id').values('status')[:1]), Value(''), output_field=TextField()),
-        )
+        qs = qs.with_current_status()
 
     if requested_by:
-        qs = qs.annotate(
-            requested_by=Subquery(SchedulingEvent.objects.filter(session=OuterRef('pk')).order_by('time', 'id').values('by')[:1]),
-        )
+        qs = qs.with_requested_by()
 
     if requested_time:
-        qs = qs.annotate(
-            requested_time=Subquery(SchedulingEvent.objects.filter(session=OuterRef('pk')).order_by('time', 'id').values('time')[:1]),
-        )
-
-    return qs
-
-def only_sessions_that_can_meet(session_qs):
-    qs = add_event_info_to_session_qs(session_qs).exclude(current_status__in=['notmeet', 'disappr', 'deleted', 'apprw'])
-
-    # Restrict graphical scheduling to meeting requests (Sessions) of type 'regular' for now
-    qs = qs.filter(type__slug='regular')
+        qs = qs.with_requested_time()
 
     return qs
 
@@ -279,9 +262,14 @@ def data_for_meetings_overview(meetings, interim_status=None):
     for m in meetings:
         m.sessions = []
 
-    sessions = add_event_info_to_session_qs(
-        Session.objects.filter(meeting__in=meetings).order_by('meeting', 'pk')
-    ).select_related('group', 'group__parent')
+    sessions = Session.objects.filter(
+        meeting__in=meetings
+    ).order_by(
+        'meeting', 'pk'
+    ).with_current_status(
+    ).select_related(
+        'group', 'group__parent'
+    )
 
     meeting_dict = {m.pk: m for m in meetings}
     for s in sessions.iterator():
diff --git a/ietf/meeting/views.py b/ietf/meeting/views.py
index 2ddb3d727..8c75c425f 100644
--- a/ietf/meeting/views.py
+++ b/ietf/meeting/views.py
@@ -72,7 +72,7 @@ from ietf.meeting.helpers import can_view_interim_request, can_approve_interim_r
 from ietf.meeting.helpers import can_edit_interim_request
 from ietf.meeting.helpers import can_request_interim_meeting, get_announcement_initial
 from ietf.meeting.helpers import sessions_post_save, is_interim_meeting_approved
-from ietf.meeting.helpers import send_interim_cancellation_notice
+from ietf.meeting.helpers import send_interim_meeting_cancellation_notice, send_interim_session_cancellation_notice
 from ietf.meeting.helpers import send_interim_approval
 from ietf.meeting.helpers import send_interim_approval_request
 from ietf.meeting.helpers import send_interim_announcement_request
@@ -2108,7 +2108,7 @@ def get_sessions(num, acronym):
     if not sessions:
         sessions = Session.objects.filter(meeting=meeting,short=acronym,type__in=['regular','plenary','other']) 
 
-    sessions = add_event_info_to_session_qs(sessions)
+    sessions = sessions.with_current_status()
 
     return sorted(sessions, key=lambda s: session_time_for_sorting(s, use_meeting_date=False))
 
@@ -2142,15 +2142,15 @@ def session_details(request, num, acronym):
                 session.times = [ x.timeslot.utc_start_time() for x in ss ]                
             else:
                 session.times = [ x.timeslot.local_start_time() for x in ss ]
-            session.cancelled = session.current_status == 'canceled'
+            session.cancelled = session.current_status in Session.CANCELED_STATUSES
             session.status = ''
         elif meeting.type_id=='interim':
             session.times = [ meeting.date ]
-            session.cancelled = session.current_status == 'canceled'
+            session.cancelled = session.current_status in Session.CANCELED_STATUSES
             session.status = ''
         else:
             session.times = []
-            session.cancelled = session.current_status == 'canceled'
+            session.cancelled = session.current_status in Session.CANCELED_STATUSES
             session.status = status_names.get(session.current_status, session.current_status)
 
         session.filtered_artifacts = list(session.sessionpresentation_set.filter(document__type__slug__in=['agenda','minutes','bluesheets']))
@@ -2987,7 +2987,8 @@ def interim_send_announcement(request, number):
         if form.is_valid():
             message = form.save(user=request.user)
             message.related_groups.add(group)
-            for session in meeting.session_set.all():
+            for session in meeting.session_set.not_canceled():
+                
                 SchedulingEvent.objects.create(
                     session=session,
                     status=SessionStatusName.objects.get(slug='sched'),
@@ -3012,7 +3013,7 @@ def interim_skip_announcement(request, number):
     meeting = get_object_or_404(Meeting, number=number)
 
     if request.method == 'POST':
-        for session in meeting.session_set.all():
+        for session in meeting.session_set.not_canceled():
             SchedulingEvent.objects.create(
                 session=session,
                 status=SessionStatusName.objects.get(slug='sched'),
@@ -3156,7 +3157,7 @@ def interim_request_cancel(request, number):
             was_scheduled = session_status.slug == 'sched'
 
             result_status = SessionStatusName.objects.get(slug='canceled' if was_scheduled else 'canceledpa')
-            for session in meeting.session_set.all():
+            for session in meeting.session_set.not_canceled():
                 SchedulingEvent.objects.create(
                     session=session,
                     status=result_status,
@@ -3164,7 +3165,7 @@ def interim_request_cancel(request, number):
                 )
 
             if was_scheduled:
-                send_interim_cancellation_notice(meeting)
+                send_interim_meeting_cancellation_notice(meeting)
 
             messages.success(request, 'Interim meeting cancelled')
             return redirect(upcoming)
@@ -3178,20 +3179,70 @@ def interim_request_cancel(request, number):
     })
 
 
+@login_required
+def interim_request_session_cancel(request, sessionid):
+    '''View for cancelling an interim meeting request'''
+    session = get_object_or_404(Session, pk=sessionid)
+    group = session.group
+    if not can_manage_group(request.user, group):
+        permission_denied(request, "You do not have permissions to cancel this session")
+    session_status = current_session_status(session)
+
+    if request.method == 'POST':
+        form = InterimCancelForm(request.POST)
+        if form.is_valid():
+            remaining_sessions = session.meeting.session_set.with_current_status().exclude(
+                current_status__in=['canceled', 'canceledpa']
+            )
+            if remaining_sessions.count() <= 1:
+                return HttpResponse('Cannot cancel only remaining session. Cancel the request instead.',
+                                    status=409)
+
+            if 'comments' in form.changed_data:
+                session.agenda_note=form.cleaned_data.get('comments')
+                session.save()
+
+            was_scheduled = session_status.slug == 'sched'
+
+            result_status = SessionStatusName.objects.get(slug='canceled' if was_scheduled else 'canceledpa')
+            SchedulingEvent.objects.create(
+                session=session,
+                status=result_status,
+                by=request.user.person,
+            )
+
+            if was_scheduled:
+                send_interim_session_cancellation_notice(session)
+
+            messages.success(request, 'Interim meeting session cancelled')
+            return redirect(interim_request_details, number=session.meeting.number)
+    else:
+        session_time = session.official_timeslotassignment().timeslot.time
+        form = InterimCancelForm(initial={'group': group.acronym, 'date': session_time.date()})
+
+    return render(request, "meeting/interim_request_cancel.html", {
+        "form": form,
+        "session": session,
+        "session_status": session_status,
+    })
+
+
 @login_required
 def interim_request_details(request, number):
     '''View details of an interim meeting request'''
     meeting = get_object_or_404(Meeting, number=number)
-    group = meeting.session_set.first().group
+    sessions_not_canceled = meeting.session_set.not_canceled()
+    first_session = meeting.session_set.first()  # first, whether or not canceled
+    group = first_session.group
+
     if not can_manage_group(request.user, group):
         permission_denied(request, "You do not have permissions to manage this meeting request")
-    sessions = meeting.session_set.all()
     can_edit = can_edit_interim_request(meeting, request.user)
     can_approve = can_approve_interim_request(meeting, request.user)
 
     if request.method == 'POST':
         if request.POST.get('approve') and can_approve_interim_request(meeting, request.user):
-            for session in meeting.session_set.all():
+            for session in sessions_not_canceled:
                 SchedulingEvent.objects.create(
                     session=session,
                     status=SessionStatusName.objects.get(slug='scheda'),
@@ -3204,7 +3255,7 @@ def interim_request_details(request, number):
                 send_interim_announcement_request(meeting)
                 return redirect(interim_pending)
         if request.POST.get('disapprove') and can_approve_interim_request(meeting, request.user):
-            for session in meeting.session_set.all():
+            for session in sessions_not_canceled:
                 SchedulingEvent.objects.create(
                     session=session,
                     status=SessionStatusName.objects.get(slug='disappr'),
@@ -3213,20 +3264,32 @@ def interim_request_details(request, number):
             messages.success(request, 'Interim meeting disapproved')
             return redirect(interim_pending)
 
-    first_session = sessions.first()
-    assignments = SchedTimeSessAssignment.objects.filter(schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None])
+    # Determine meeting status from non-canceled sessions, if any.
+    # N.b., meeting_status may be None after either of these code paths,
+    # though I am not sure what circumstances would cause this.
+    if sessions_not_canceled.count() > 0:
+        meeting_status = current_session_status(sessions_not_canceled.first())
+    else:
+        meeting_status = current_session_status(first_session)
+
+    meeting_assignments = SchedTimeSessAssignment.objects.filter(
+        schedule__in=[meeting.schedule, meeting.schedule.base if meeting.schedule else None]
+    ).select_related(
+        'session', 'timeslot'
+    )
+    for ma in meeting_assignments:
+        ma.status = current_session_status(ma.session)
+        ma.can_be_canceled = ma.status.slug in ('sched', 'scheda', 'apprw')
 
     return render(request, "meeting/interim_request_details.html", {
         "meeting": meeting,
-        "sessions": sessions,
-        "assignments": assignments,
-        "group": first_session.group,
+        "meeting_assignments": meeting_assignments,
+        "group": group,
         "requester": session_requested_by(first_session),
-        "session_status": current_session_status(first_session),
+        "meeting_status": meeting_status or SessionStatusName.objects.get(slug='canceled'),
         "can_edit": can_edit,
         "can_approve": can_approve})
 
-
 @login_required
 def interim_request_edit(request, number):
     '''Edit details of an interim meeting reqeust'''
diff --git a/ietf/secr/meetings/views.py b/ietf/secr/meetings/views.py
index bb599d0e0..0613b8c27 100644
--- a/ietf/secr/meetings/views.py
+++ b/ietf/secr/meetings/views.py
@@ -20,7 +20,6 @@ from ietf.meeting.forms import duration_string
 from ietf.meeting.helpers import get_meeting, make_materials_directories, populate_important_dates
 from ietf.meeting.models import Meeting, Session, Room, TimeSlot, SchedTimeSessAssignment, Schedule, SchedulingEvent
 from ietf.meeting.utils import add_event_info_to_session_qs
-from ietf.meeting.utils import only_sessions_that_can_meet
 from ietf.name.models import SessionStatusName
 from ietf.group.models import Group, GroupEvent
 from ietf.secr.meetings.blue_sheets import create_blue_sheets
@@ -662,9 +661,7 @@ def regular_sessions(request, meeting_id, schedule_name):
     meeting = get_object_or_404(Meeting, number=meeting_id)
     schedule = get_object_or_404(Schedule, meeting=meeting, name=schedule_name)
 
-    sessions = add_event_info_to_session_qs(
-        only_sessions_that_can_meet(meeting.session_set)
-    ).order_by('group__acronym')
+    sessions = meeting.session_set.that_can_meet().order_by('group__acronym')
 
     if request.method == 'POST':
         if 'cancel' in request.POST:
diff --git a/ietf/templates/meeting/interim_announcement.txt b/ietf/templates/meeting/interim_announcement.txt
index d832b7be7..074394099 100644
--- a/ietf/templates/meeting/interim_announcement.txt
+++ b/ietf/templates/meeting/interim_announcement.txt
@@ -1,11 +1,11 @@
 {% load ietf_filters %}{% if is_change %}MEETING DETAILS HAVE CHANGED.  SEE LATEST DETAILS BELOW.
 
 {% endif %}The {{ group.name }} ({{ group.acronym }}) {% if group.type.slug == 'wg' and group.state.slug == 'bof' %}BOF{% else %}{{group.type.name}}{% endif %} will hold
-{% if meeting.session_set.count == 1 %}a{% if meeting.city %}n {% else %} virtual {% endif %}interim meeting on {{ meeting.date }} from {{ assignments.first.timeslot.time | date:"H:i" }} to {{ assignments.first.timeslot.end_time | date:"H:i" }} {{ meeting.time_zone}}{% if meeting.time_zone != 'UTC' %} ({{ assignments.first.timeslot.utc_start_time | date:"H:i" }} to {{ assignments.first.timeslot.utc_end_time | date:"H:i" }} UTC){% endif %}.
+{% if assignments.count == 1 %}a{% if meeting.city %}n {% else %} virtual {% endif %}interim meeting on {{ meeting.date }} from {{ assignments.first.timeslot.time | date:"H:i" }} to {{ assignments.first.timeslot.end_time | date:"H:i" }} {{ meeting.time_zone}}{% if meeting.time_zone != 'UTC' %} ({{ assignments.first.timeslot.utc_start_time | date:"H:i" }} to {{ assignments.first.timeslot.utc_end_time | date:"H:i" }} UTC){% endif %}.
 {% else %}a multi-day {% if not meeting.city %}virtual {% endif %}interim meeting.
 
 {% for assignment in assignments %}Session {{ forloop.counter }}:
-{{ assignment.timeslot.time | date:"Y-m-d" }}     {{ assignment.timeslot.time | date:"H:i" }} to {{ assignment.timeslot.end_time | date:"H:i" }}  {{ meeting.time_zone }}{% if meeting.time_zone != 'UTC' %}({{ assignment.timeslot.utc_start_time | date:"H:i" }} to {{ assignment.timeslot.utc_end_time | date:"H:i" }} UTC){% endif %}
+{{ assignment.timeslot.time | date:"Y-m-d" }}     {{ assignment.timeslot.time | date:"H:i" }} to {{ assignment.timeslot.end_time | date:"H:i" }} {{ meeting.time_zone }}{% if meeting.time_zone != 'UTC' %}({{ assignment.timeslot.utc_start_time | date:"H:i" }} to {{ assignment.timeslot.utc_end_time | date:"H:i" }} UTC){% endif %}
 {% endfor %}{% endif %}
 {% if meeting.city %}Meeting Location:
 {{ meeting.city }}, {{ meeting.country }}
diff --git a/ietf/templates/meeting/interim_info.txt b/ietf/templates/meeting/interim_info.txt
index 11903655d..4bb950b7d 100644
--- a/ietf/templates/meeting/interim_info.txt
+++ b/ietf/templates/meeting/interim_info.txt
@@ -8,7 +8,7 @@
 Country: {{ meeting.country }}
 {% else %}Meeting Type: Virtual Meeting{% endif %}
 
-{% for session in meeting.session_set.all %}Session {{ forloop.counter }}:
+{% for session in meeting.session_set.not_canceled %}Session {{ forloop.counter }}:
 
 Date: {{ session.official_timeslotassignment.timeslot.time|date:"Y-m-d" }}
 Start Time: {{ session.official_timeslotassignment.timeslot.time|date:"H:i" }} {{ meeting.time_zone }}
diff --git a/ietf/templates/meeting/interim_cancellation_notice.txt b/ietf/templates/meeting/interim_meeting_cancellation_notice.txt
similarity index 100%
rename from ietf/templates/meeting/interim_cancellation_notice.txt
rename to ietf/templates/meeting/interim_meeting_cancellation_notice.txt
diff --git a/ietf/templates/meeting/interim_request_cancel.html b/ietf/templates/meeting/interim_request_cancel.html
index 95f8d3c21..9e2c265e1 100644
--- a/ietf/templates/meeting/interim_request_cancel.html
+++ b/ietf/templates/meeting/interim_request_cancel.html
@@ -13,17 +13,18 @@
 
 {% block content %}
   {% origin %}
-  <h1>{% block title %}Cancel Interim Meeting {% if session_status != "sched" %}Request{% endif %}{% endblock %}</h1>
+  <h1>{% block title %}Cancel Interim {% if meeting %}Meeting{% else %}Session{% endif %} {% if session_status != "sched" %}Request{% endif %}{% endblock %}</h1>
 
   <form id="interim-request-cancel-form" role="form" method="post" class="form-horizontal">
     {% csrf_token %}
     
     {% bootstrap_form form layout='horizontal' %}
 
-    <div class="form-group"
+    <div class="form-group">
     {% buttons %}
       <button type="submit" class="btn btn-primary">Submit</button>
-      <a class="btn btn-default pull-right" href="{% url 'ietf.meeting.views.interim_request_details' number=meeting.number %}">Back</a>
+        {% if meeting %}<a class="btn btn-default pull-right" href="{% url 'ietf.meeting.views.interim_request_details' number=meeting.number %}">Back</a>
+        {% else %}<a class="btn btn-default pull-right" href="{% url 'ietf.meeting.views.interim_request_details' number=session.meeting.number %}">Back</a>{% endif %}
     {% endbuttons %}
     </div>
     
diff --git a/ietf/templates/meeting/interim_request_details.html b/ietf/templates/meeting/interim_request_details.html
index 3dda8ecbb..286a96ec0 100644
--- a/ietf/templates/meeting/interim_request_details.html
+++ b/ietf/templates/meeting/interim_request_details.html
@@ -19,18 +19,21 @@
     <dt>Requested By</dt>
     <dd>{{ requester }}
     <dt>Status</dt>
-    <dd>{{ session_status.name }}</dd>
+    <dd>{{ meeting_status.name }}</dd>
     <dt>City</dt>
     <dd>{{ meeting.city }}</dd>
     <dt>Country</dt>
     <dd>{{ meeting.country }}</dd>
     <dt>Timezone</dt>
     <dd>{{ meeting.time_zone }}</dd>
-    {% for assignment in assignments %}
+    {% for assignment in meeting_assignments %}
       <br>
+      {% if meeting_assignments|length > 1 %}
+          <dt>Session</dt><dd>{{ assignment.status.name }}</dd>
+      {% endif %}
       <dt>Date</dt>
       <dd>{{ assignment.timeslot.time|date:"Y-m-d" }}
-      <dt>Start Time</dt>
+        <dt>Start Time</dt>
       <dd>{{ assignment.timeslot.time|date:"H:i" }} {% if meeting.time_zone != 'UTC' %}( {{ assignment.timeslot.utc_start_time|date:"H:i"}} UTC ){% endif %}
       <dt>Duration</dt>
       <dd>{{ assignment.session.requested_duration|format_timedelta }}
@@ -38,36 +41,44 @@
       <dd>{{ assignment.session.remote_instructions }}
       <dt>Additional Info</dt>
       <dd>{{ assignment.session.agenda_note }}</dd>
+      {% if meeting_assignments|length > 1 %}
+      {% if can_edit and assignment.can_be_canceled %}
+        <dt>Actions</dt>
+        <dd><a class="btn btn-default btn-sm" href="{% url 'ietf.meeting.views.interim_request_session_cancel' sessionid=assignment.session.pk %}">Cancel Session</a></dd>
+      {% endif %}
+      {% endif %}
     {% endfor %}
   </dl>
 
   <form method="post">
   {% csrf_token %}
+  {%  with meeting_status.slug as status_slug %}    
   {% if can_edit %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_request_edit' number=meeting.number %}">Edit</a>
   {% endif %}
-  {% if can_approve and session_status.slug == 'apprw' %}
+  {% if can_approve and status_slug == 'apprw' %}
     <input class="btn btn-default" type="submit" value="Approve" name='approve' />
     <input class="btn btn-default" type="submit" value="Disapprove" name='disapprove' />
   {% endif %}
-  {% if user|has_role:"Secretariat" and session_status.slug == 'scheda' %}
+  {% if user|has_role:"Secretariat" and status_slug == 'scheda' %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_send_announcement' number=meeting.number %}">Announce</a>
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_skip_announcement' number=meeting.number %}">Skip Announcement</a>
   {% endif %}
   {% if can_edit %}
-    {% if session_status.slug == 'apprw' or session_status.slug == 'scheda' or session_status.slug == 'sched' %}
+    {% if status_slug == 'apprw' or status_slug == 'scheda' or status_slug == 'sched' %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_request_cancel' number=meeting.number %}">Cancel Meeting</a>
     {% endif %}
   {% endif %}
-  {% if session_status.slug == "apprw" %}
+  {% if status_slug == "apprw" %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_pending' %}">Back</a>
-  {% elif session_status.slug == "scheda" %}
+  {% elif status_slug == "scheda" %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.interim_announce' %}">Back</a>
-  {% elif session_status.slug == "sched" %}
+  {% elif status_slug == "sched" %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.session_details' num=meeting.number acronym=meeting.session_set.first.group.acronym %}">Back</a>
   {% else %}
         <a class="btn btn-default" href="{% url 'ietf.meeting.views.upcoming' %}">Back</a>
   {% endif %}
+  {% endwith %}
   </form>
 
 {% endblock %}
diff --git a/ietf/templates/meeting/interim_session_cancellation_notice.txt b/ietf/templates/meeting/interim_session_cancellation_notice.txt
new file mode 100644
index 000000000..7be4c612b
--- /dev/null
+++ b/ietf/templates/meeting/interim_session_cancellation_notice.txt
@@ -0,0 +1,7 @@
+{% load ams_filters %}
+{% if session.name %}The "{{ session.name }}"{% else %}A{% endif %} session of the {{ group.name }} ({{ group.acronym }}) {% if not session.meeting.city %}virtual {% endif %}{% if is_multi_day %}multi-day {% endif %}
+interim meeting has been cancelled. This session had been scheduled for {{ meeting.date|date:"Y-m-d" }} from {{ start_time|time:"H:i" }} to {{ end_time|time:"H:i" }} {{ meeting.time_zone }}.
+
+{{ session.agenda_note }}
+
+