Merge ~adam-collard/maas:2.8-fix-1884112-count-aggregates into maas:2.8

[Adam Collard]

[2.8 backport] Use distinct=True to avoid Django gotcha with multiple aggregations

Fixes LP:1884112, work around https://code.djangoproject.com/ticket/10060

[Adam Collard (adam-collard)]

review: Approve

diff --git a/src/maasserver/websockets/handlers/tests/test_user.py b/src/maasserver/websockets/handlers/tests/test_user.py
index 2eaecaa..f62c79c 100644
--- a/src/maasserver/websockets/handlers/tests/test_user.py
+++ b/src/maasserver/websockets/handlers/tests/test_user.py
@@ -1,4 +1,4 @@
-# Copyright 2015-2018 Canonical Ltd.  This software is licensed under the
+# Copyright 2015-2020 Canonical Ltd.  This software is licensed under the
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 """Tests for `maasserver.websockets.handlers.user`"""
@@ -10,6 +10,7 @@ import datetime
 from django.contrib.auth.models import User
 from testtools.testcase import TestCase
 
+from maasserver.enum import NODE_STATUS
 from maasserver.models.event import Event
 from maasserver.models.user import SYSTEM_USERS
 from maasserver.permissions import (
@@ -64,15 +65,17 @@ class TestUserHandler(MAASServerTestCase):
         # testtools' assertRaises predates unittest's which has
         # support for context-manager
         self.assertRaises = super(TestCase, self).assertRaises
+        # likewise assertEqual in unittest has gotten much better
+        self.assertEqual = super(TestCase, self).assertEqual
 
-    def dehydrate_user(self, user, sshkeys_count=0, for_self=False):
+    def dehydrate_user(self, user, for_self=False):
         data = {
             "id": user.id,
             "username": user.username,
             "last_name": user.last_name,
             "email": user.email,
             "is_superuser": user.is_superuser,
-            "sshkeys_count": sshkeys_count,
+            "sshkeys_count": user.sshkey_set.count(),
             "last_login": dehydrate_datetime(user.last_login),
             "is_local": user.userprofile.is_local,
             "completed_intro": user.userprofile.completed_intro,
@@ -163,6 +166,21 @@ class TestUserHandler(MAASServerTestCase):
             [self.dehydrate_user(user, for_self=True)], handler.list({})
         )
 
+    def test_list_with_sshkeys_and_machines(self):
+        user, keys = factory.make_user_with_keys()
+        num_machines = 3
+        for _ in range(num_machines):
+            node = factory.make_Node(status=NODE_STATUS.READY)
+            node.acquire(user)
+        handler = UserHandler(user, {}, None)
+        users_from_ws = handler.list({})
+        self.assertEqual(
+            [self.dehydrate_user(user, for_self=True)], users_from_ws
+        )
+        user_from_ws = users_from_ws[0]
+        self.assertEqual(user_from_ws["sshkeys_count"], len(keys))
+        self.assertEqual(user_from_ws["machines_count"], num_machines)
+
     def test_auth_user(self):
         user = factory.make_User()
         handler = UserHandler(user, {}, None)
diff --git a/src/maasserver/websockets/handlers/user.py b/src/maasserver/websockets/handlers/user.py
index 97f14fd..cba0ce6 100644
--- a/src/maasserver/websockets/handlers/user.py
+++ b/src/maasserver/websockets/handlers/user.py
@@ -1,4 +1,4 @@
-# Copyright 2015-2018 Canonical Ltd.  This software is licensed under the
+# Copyright 2015-2020 Canonical Ltd.  This software is licensed under the
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 """The user handler for the WebSocket connection."""
@@ -35,7 +35,8 @@ class UserHandler(Handler):
         queryset = (
             User.objects.filter(is_active=True)
             .annotate(
-                sshkeys_count=Count("sshkey"), machines_count=Count("node")
+                sshkeys_count=Count("sshkey", distinct=True),
+                machines_count=Count("node", distinct=True),
             )
             .select_related("userprofile")
         )