stream: Add do_change_can_remove_subscribers_group and field to objects.

This commit adds do_change_can_remove_subscriber_group function for
changing can_remove_subscribers_group field of a stream. We also add
can_remove_subscribers_group_id field to stream and subscription
objects.

This function will be helpful for writing tests in next commit.
We would add API and UI support to change this setting in further
commits.

frontend_tests/node_tests/lib/events.js

@@ -50,6 +50,7 @@ exports.test_streams = {
         is_web_public: false,
         message_retention_days: null,
         stream_post_policy: 1,
+        can_remove_subscribers_group_id: 2,
     },
     test: {
         name: "test",
@@ -64,6 +65,7 @@ exports.test_streams = {
         is_announcement_only: false,
         message_retention_days: null,
         stream_post_policy: 1,
+        can_remove_subscribers_group_id: 2,
     },
 };
 

templates/zerver/api/changelog.md

@@ -20,6 +20,13 @@ format used by the Zulip server that they are interacting with.
 
 ## Changes in Zulip 6.0
 
+**Feature level 142**
+
+* [`GET users/me/subscriptions`](/api/get-subscriptions), [`GET
+  /streams`](/api/get-streams), [`POST /register`](/api/register-queue),
+  [`GET /events`](/api/get-events): Added `can_remove_subscribers_group_id`
+  field to Stream and Subscription objects.
+
 **Feature level 141**
 
 * [`POST /register`](/api/register-queue), [`PATCH

version.py

@@ -33,7 +33,7 @@ DESKTOP_WARNING_VERSION = "5.4.3"
 # Changes should be accompanied by documentation explaining what the
 # new level means in templates/zerver/api/changelog.md, as well as
 # "**Changes**" entries in the endpoint's documentation in `zulip.yaml`.
-API_FEATURE_LEVEL = 141
+API_FEATURE_LEVEL = 142
 
 # Bump the minor PROVISION_VERSION to indicate that folks should provision
 # only when going from an old version of the code to a newer version. Bump

zerver/actions/streams.py

@@ -68,6 +68,7 @@ from zerver.models import (
     Recipient,
     Stream,
     Subscription,
+    UserGroup,
     UserProfile,
     active_non_guest_user_ids,
     get_system_bot,
@@ -289,6 +290,7 @@ def send_subscription_add_events(
                 stream_weekly_traffic=stream_info.stream_weekly_traffic,
                 subscribers=stream_info.subscribers,
                 # Fields from Stream.API_FIELDS
+                can_remove_subscribers_group_id=stream_dict["can_remove_subscribers_group_id"],
                 date_created=stream_dict["date_created"],
                 description=stream_dict["description"],
                 first_message_id=stream_dict["first_message_id"],
@@ -1317,3 +1319,39 @@ def do_change_stream_message_retention_days(
         old_value=old_message_retention_days_value,
         new_value=message_retention_days,
     )
+
+
+def do_change_can_remove_subscribers_group(
+    stream: Stream, user_group: UserGroup, *, acting_user: Optional[UserProfile] = None
+) -> None:
+    old_user_group = stream.can_remove_subscribers_group
+    old_user_group_id = None
+    if old_user_group is not None:
+        old_user_group_id = old_user_group.id
+
+    stream.can_remove_subscribers_group = user_group
+    stream.save()
+    RealmAuditLog.objects.create(
+        realm=stream.realm,
+        acting_user=acting_user,
+        modified_stream=stream,
+        event_type=RealmAuditLog.STREAM_CAN_REMOVE_SUBSCRIBERS_GROUP_CHANGED,
+        event_time=timezone_now(),
+        extra_data=orjson.dumps(
+            {
+                RealmAuditLog.OLD_VALUE: old_user_group_id,
+                RealmAuditLog.NEW_VALUE: user_group.id,
+            }
+        ).decode(),
+    )
+    event = dict(
+        op="update",
+        type="stream",
+        property="can_remove_subscribers_group_id",
+        value=user_group.id,
+        stream_id=stream.id,
+        name=stream.name,
+    )
+    transaction.on_commit(
+        lambda: send_event(stream.realm, event, can_access_stream_user_ids(stream))
+    )

zerver/lib/event_schema.py

@@ -50,6 +50,7 @@ from zerver.models import Realm, RealmUserDefault, Stream, UserProfile
 # These fields are used for "stream" events, and are included in the
 # larger "subscription" events that also contain personal settings.
 basic_stream_fields = [
+    ("can_remove_subscribers_group_id", int),
     ("date_created", int),
     ("description", str),
     ("first_message_id", OptionalType(int)),
@@ -1287,6 +1288,9 @@ def check_stream_update(
     elif prop == "stream_post_policy":
         assert extra_keys == set()
         assert value in Stream.STREAM_POST_POLICY_TYPES
+    elif prop == "can_remove_subscribers_group_id":
+        assert extra_keys == set()
+        assert isinstance(value, int)
     else:
         raise AssertionError(f"Unknown property: {prop}")
 

zerver/lib/subscription_info.py

@@ -40,6 +40,7 @@ def get_web_public_subs(realm: Realm) -> SubscriptionInfo:
     subscribed = []
     for stream in get_web_public_streams_queryset(realm):
         # Add Stream fields.
+        can_remove_subscribers_group_id = stream.can_remove_subscribers_group_id
         date_created = datetime_to_timestamp(stream.date_created)
         description = stream.description
         first_message_id = stream.first_message_id
@@ -71,6 +72,7 @@ def get_web_public_subs(realm: Realm) -> SubscriptionInfo:
 
         sub = SubscriptionStreamDict(
             audible_notifications=audible_notifications,
+            can_remove_subscribers_group_id=can_remove_subscribers_group_id,
             color=color,
             date_created=date_created,
             description=description,
@@ -110,6 +112,7 @@ def build_stream_dict_for_sub(
     recent_traffic: Dict[int, int],
 ) -> SubscriptionStreamDict:
     # Handle Stream.API_FIELDS
+    can_remove_subscribers_group_id = raw_stream_dict["can_remove_subscribers_group_id"]
     date_created = datetime_to_timestamp(raw_stream_dict["date_created"])
     description = raw_stream_dict["description"]
     first_message_id = raw_stream_dict["first_message_id"]
@@ -153,6 +156,7 @@ def build_stream_dict_for_sub(
     # Our caller may add a subscribers field.
     return SubscriptionStreamDict(
         audible_notifications=audible_notifications,
+        can_remove_subscribers_group_id=can_remove_subscribers_group_id,
         color=color,
         date_created=date_created,
         description=description,
@@ -182,6 +186,7 @@ def build_stream_dict_for_never_sub(
     raw_stream_dict: RawStreamDict,
     recent_traffic: Dict[int, int],
 ) -> NeverSubscribedStreamDict:
+    can_remove_subscribers_group_id = raw_stream_dict["can_remove_subscribers_group_id"]
     date_created = datetime_to_timestamp(raw_stream_dict["date_created"])
     description = raw_stream_dict["description"]
     first_message_id = raw_stream_dict["first_message_id"]
@@ -202,6 +207,7 @@ def build_stream_dict_for_never_sub(
 
     # Our caller may add a subscribers field.
     return NeverSubscribedStreamDict(
+        can_remove_subscribers_group_id=can_remove_subscribers_group_id,
         date_created=date_created,
         description=description,
         first_message_id=first_message_id,

zerver/lib/types.py

@@ -177,6 +177,7 @@ class RawStreamDict(TypedDict):
     are needed to encode the stream for the API.
     """
 
+    can_remove_subscribers_group_id: int
     date_created: datetime.datetime
     description: str
     email_token: str
@@ -216,6 +217,7 @@ class SubscriptionStreamDict(TypedDict):
     """
 
     audible_notifications: Optional[bool]
+    can_remove_subscribers_group_id: int
     color: str
     date_created: int
     description: str
@@ -242,6 +244,7 @@ class SubscriptionStreamDict(TypedDict):
 
 
 class NeverSubscribedStreamDict(TypedDict):
+    can_remove_subscribers_group_id: int
     date_created: int
     description: str
     first_message_id: Optional[int]
@@ -264,6 +267,7 @@ class APIStreamDict(TypedDict):
     with few exceptions and possible additional fields.
     """
 
+    can_remove_subscribers_group_id: int
     date_created: int
     description: str
     first_message_id: Optional[int]

zerver/models.py

@@ -2552,6 +2552,7 @@ class Stream(models.Model):
         "name",
         "rendered_description",
         "stream_post_policy",
+        "can_remove_subscribers_group_id",
     ]
 
     @staticmethod
@@ -2561,6 +2562,7 @@ class Stream(models.Model):
 
     def to_dict(self) -> APIStreamDict:
         return APIStreamDict(
+            can_remove_subscribers_group_id=self.can_remove_subscribers_group_id,
             date_created=datetime_to_timestamp(self.date_created),
             description=self.description,
             first_message_id=self.first_message_id,
@@ -4364,6 +4366,7 @@ class AbstractRealmAuditLog(models.Model):
     STREAM_REACTIVATED = 604
     STREAM_MESSAGE_RETENTION_DAYS_CHANGED = 605
     STREAM_PROPERTY_CHANGED = 607
+    STREAM_CAN_REMOVE_SUBSCRIBERS_GROUP_CHANGED = 608
 
     # The following values are only for RemoteZulipServerAuditLog
     # Values should be exactly 10000 greater than the corresponding

zerver/openapi/zulip.yaml

@@ -644,6 +644,7 @@ paths:
                                         "in_home_view": true,
                                         "email_address": "test_stream.af64447e9e39374841063747ade8e6b0.show-sender@testserver",
                                         "stream_weekly_traffic": null,
+                                        "can_remove_subscribers_group_id": 2,
                                         "subscribers": [10],
                                       },
                                     ],
@@ -1143,6 +1144,7 @@ paths:
                                         "first_message_id": null,
                                         "message_retention_days": null,
                                         "is_announcement_only": false,
+                                        "can_remove_subscribers_group_id": 2,
                                       },
                                     ],
                                   "id": 0,
@@ -1188,6 +1190,7 @@ paths:
                                         "first_message_id": null,
                                         "message_retention_days": null,
                                         "is_announcement_only": false,
+                                        "can_remove_subscribers_group_id": 2,
                                       },
                                     ],
                                   "id": 0,
@@ -1745,6 +1748,7 @@ paths:
                                               "first_message_id": 1,
                                               "message_retention_days": null,
                                               "is_announcement_only": false,
+                                              "can_remove_subscribers_group_id": 2,
                                             },
                                             {
                                               "name": "Denmark",
@@ -1758,6 +1762,7 @@ paths:
                                               "first_message_id": 4,
                                               "message_retention_days": null,
                                               "is_announcement_only": false,
+                                              "can_remove_subscribers_group_id": 2,
                                             },
                                             {
                                               "name": "Verona",
@@ -1771,6 +1776,7 @@ paths:
                                               "first_message_id": 6,
                                               "message_retention_days": null,
                                               "is_announcement_only": false,
+                                              "can_remove_subscribers_group_id": 2,
                                             },
                                           ],
                                       },
@@ -1815,6 +1821,7 @@ paths:
                                         "first_message_id": 1,
                                         "message_retention_days": null,
                                         "is_announcement_only": false,
+                                        "can_remove_subscribers_group_id": 2,
                                       },
                                     ],
                                   "id": 0,
@@ -10089,6 +10096,7 @@ paths:
                                 first_message_id:
                                   nullable: true
                                 is_announcement_only: {}
+                                can_remove_subscribers_group_id: {}
                                 stream_weekly_traffic:
                                   type: integer
                                   nullable: true
@@ -13879,6 +13887,7 @@ paths:
                                 first_message_id:
                                   nullable: true
                                 is_announcement_only: {}
+                                can_remove_subscribers_group_id: {}
                                 is_default:
                                   type: boolean
                                   description: |
@@ -13989,6 +13998,7 @@ paths:
                             "rendered_description": "<p>A Scandinavian country</p>",
                             "stream_id": 7,
                             "stream_post_policy": 1,
+                            "can_remove_subscribers_group_id": 2,
                           },
                       }
         "400":
@@ -15075,6 +15085,7 @@ components:
             first_message_id:
               nullable: true
             is_announcement_only: {}
+            can_remove_subscribers_group_id: {}
     BasicStreamBase:
       type: object
       description: |
@@ -15176,6 +15187,13 @@ components:
 
             **Changes**: Deprecated in Zulip 3.0 (feature level 1). Clients
             should use `stream_post_policy` instead.
+        can_remove_subscribers_group_id:
+          type: integer
+          description: |
+            ID of the user group whose members are allowed to unsubscribe others
+            from the stream.
+
+            **Changes**: New in Zulip 6.0 (feature level 142).
     BasicBot:
       allOf:
         - $ref: "#/components/schemas/BasicBotBase"
@@ -15792,6 +15810,13 @@ components:
 
             Null means the stream was recently created and there is
             insufficient data to estimate the average traffic.
+        can_remove_subscribers_group_id:
+          type: integer
+          description: |
+            ID of the user group whose members are allowed to unsubscribe others
+            from the stream.
+
+            **Changes**: New in Zulip 6.0 (feature level 142).
     DefaultStreamGroup:
       type: object
       description: |

zerver/tests/test_events.py

@@ -79,6 +79,7 @@ from zerver.actions.realm_settings import (
 from zerver.actions.streams import (
     bulk_add_subscriptions,
     bulk_remove_subscriptions,
+    do_change_can_remove_subscribers_group,
     do_change_stream_description,
     do_change_stream_message_retention_days,
     do_change_stream_permission,
@@ -2885,6 +2886,17 @@ class SubscribeActionTest(BaseAction):
         events = self.verify_action(action, include_subscribers=include_subscribers, num_events=2)
         check_stream_update("events[0]", events[0])
 
+        moderators_group = UserGroup.objects.get(
+            name=UserGroup.MODERATORS_GROUP_NAME,
+            is_system_group=True,
+            realm=self.user_profile.realm,
+        )
+        action = lambda: do_change_can_remove_subscribers_group(
+            stream, moderators_group, acting_user=self.example_user("hamlet")
+        )
+        events = self.verify_action(action, include_subscribers=include_subscribers, num_events=1)
+        check_stream_update("events[0]", events[0])
+
         # Subscribe to a totally new invite-only stream, so it's just Hamlet on it
         stream = self.make_stream("private", self.user_profile.realm, invite_only=True)
         stream.message_retention_days = 10