utils: Rework how notifications are selected

The current method of filtering valid patches from invalid ones is
effective, but incompatible with forthcoming rework that splits
the 'Patch' model into two models. Rework this, removing the
soon-to-be non-existant 'User.patch' reference.

Signed-off-by: Stephen Finucane <stephen.finucane@intel.com>

diff --git a/patchwork/utils.py b/patchwork/utils.py
index 2070131c9897ab48733c7e21699fbf29b6d33e28..b496af49ea019b0d1260959e6226a690f7adaae2 100644 (file)
--- a/patchwork/utils.py
+++ b/patchwork/utils.py
@@ -26,7 +26,7 @@ from django.conf import settings
 from django.contrib.auth.models import User
 from django.contrib.sites.models import Site
 from django.core.mail import EmailMessage
-from django.db.models import Max, Q, F
+from django.db.models import Count, Q, F
 
 from patchwork.compat import render_to_string
 from patchwork.models import (PatchChangeNotification, EmailOptout,
@@ -37,14 +37,16 @@ def send_notifications():
     date_limit = datetime.datetime.now() - datetime.timedelta(
         minutes=settings.NOTIFICATION_DELAY_MINUTES)
 
-    # This gets funky: we want to filter out any notifications that should
-    # be grouped with other notifications that aren't ready to go out yet. To
-    # do that, we join back onto PatchChangeNotification (PCN -> Patch ->
-    # Person -> Patch -> max(PCN.last_modified)), filtering out any maxima
-    # that are with the date_limit.
-    qs = PatchChangeNotification.objects.annotate(
-        m=Max('patch__submitter__patch__patchchangenotification'
-              '__last_modified')).filter(m__lt=date_limit)
+    # We delay sending notifications to a user if they have other
+    # notifications that are still in the "pending" state. To do this,
+    # we compare the total number of patch change notifications queued
+    # for each user against the number of "ready" notifications.
+    qs = PatchChangeNotification.objects.all()
+    qs2 = PatchChangeNotification.objects\
+        .filter(last_modified__lt=date_limit)\
+        .values('patch__submitter')\
+        .annotate(count=Count('patch__submitter'))
+    qs2 = {elem['patch__submitter']: elem['count'] for elem in qs2}
 
     groups = itertools.groupby(qs.order_by('patch__submitter'),
                                lambda n: n.patch.submitter)
@@ -53,6 +55,10 @@ def send_notifications():
 
     for (recipient, notifications) in groups:
         notifications = list(notifications)
+
+        if recipient.id not in qs2 or qs2[recipient.id] < len(notifications):
+            continue
+
         projects = set([n.patch.project.linkname for n in notifications])
 
         def delete_notifications():