data_import: Set a default announcements channel for 3rd party imports.

For Slack, Mattermost and RocketChat, set the default announcement
channels if the sane default channel is available in the import.

The next commit will add a mechanism to choose an alternative default if
the expected channel name is not present.

Addresses the major part of #34984.

zerver/data_import/mattermost.py

@@ -140,7 +140,11 @@ def convert_user_data(
     user_handler.validate_user_emails()
 
 
+MATTERMOST_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME = "Town Square"
+
+
 def convert_channel_data(
+    realm: ZerverFieldsT,
     channel_data: list[ZerverFieldsT],
     user_data_map: dict[str, dict[str, Any]],
     subscriber_handler: SubscriberHandler,
@@ -149,6 +153,8 @@ def convert_channel_data(
     realm_id: int,
     team_name: str,
 ) -> list[ZerverFieldsT]:
+    zerver_realm = realm["zerver_realm"]
+
     channel_data_list = [d for d in channel_data if d["team"] == team_name]
 
     channel_members_map: dict[str, list[str]] = {}
@@ -223,6 +229,11 @@ def convert_channel_data(
             users=channel_users,
             stream_id=stream_id,
         )
+
+        if channel_dict["display_name"] == MATTERMOST_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME:
+            zerver_realm[0]["new_stream_announcements_stream"] = stream["id"]
+            zerver_realm[0]["zulip_update_announcements_stream"] = stream["id"]
+
         streams.append(stream)
     return streams
 
@@ -923,6 +934,7 @@ def do_convert_data(mattermost_data_dir: str, output_dir: str, masking_content:
         )
 
         zerver_stream = convert_channel_data(
+            realm=realm,
             channel_data=mattermost_data["channel"],
             user_data_map=username_to_user,
             subscriber_handler=subscriber_handler,

zerver/data_import/rocketchat.py

@@ -157,12 +157,18 @@ def get_stream_name(rc_channel: dict[str, Any]) -> str:
     return stream_name
 
 
+ROCKETCHAT_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME = "general"
+
+
 def convert_channel_data(
+    realm: ZerverFieldsT,
     room_id_to_room_map: dict[str, dict[str, Any]],
     team_id_to_team_map: dict[str, dict[str, Any]],
     stream_id_mapper: IdMapper[str],
     realm_id: int,
 ) -> list[ZerverFieldsT]:
+    zerver_realm = realm["zerver_realm"]
+
     streams = []
 
     for rc_room_id, channel_dict in room_id_to_room_map.items():
@@ -196,6 +202,11 @@ def convert_channel_data(
             invite_only=invite_only,
             stream_post_policy=stream_post_policy,
         )
+
+        if stream_name == ROCKETCHAT_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME:
+            zerver_realm[0]["new_stream_announcements_stream"] = stream["id"]
+            zerver_realm[0]["zulip_update_announcements_stream"] = stream["id"]
+
         streams.append(stream)
 
     return streams
@@ -1133,6 +1144,7 @@ def do_convert_data(rocketchat_data_dir: str, output_dir: str) -> None:
     )
 
     zerver_stream = convert_channel_data(
+        realm=realm,
         room_id_to_room_map=room_id_to_room_map,
         team_id_to_team_map=team_id_to_team_map,
         stream_id_mapper=stream_id_mapper,

zerver/data_import/slack.py

@@ -537,6 +537,9 @@ def get_user_timezone(user: ZerverFieldsT) -> str:
     return timezone
 
 
+SLACK_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME = "general"
+
+
 def channels_to_zerver_stream(
     slack_data_dir: str,
     realm_id: int,
@@ -558,6 +561,8 @@ def channels_to_zerver_stream(
     """
     logging.info("######### IMPORTING CHANNELS STARTED #########\n")
 
+    zerver_realm = realm["zerver_realm"]
+
     added_channels = {}
     added_mpims = {}
     dm_members = {}
@@ -619,6 +624,13 @@ def channels_to_zerver_stream(
             recipient_id_count += 1
             logging.info("%s -> created", channel["name"])
 
+            if channel["name"] == SLACK_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME:
+                zerver_realm[0]["new_stream_announcements_stream"] = stream["id"]
+                zerver_realm[0]["zulip_update_announcements_stream"] = stream["id"]
+                logging.info(
+                    "Using the channel %s as default announcements channel.", channel["name"]
+                )
+
             # TODO map Slack's pins to Zulip's stars
             # There is the security model that Slack's pins are known to the team owner
             # as evident from where it is stored at (channels)

zerver/tests/test_mattermost_importer.py

@@ -224,6 +224,9 @@ class MatterMostImporter(ZulipTestCase):
         user_id_mapper = IdMapper[str]()
         team_name = "gryffindor"
 
+        mock_realm_dict: ZerverFieldsT = dict(zerver_realm=[dict()])
+        zerver_realm = mock_realm_dict["zerver_realm"]
+
         convert_user_data(
             user_handler=user_handler,
             user_id_mapper=user_id_mapper,
@@ -232,15 +235,20 @@ class MatterMostImporter(ZulipTestCase):
             team_name=team_name,
         )
 
-        zerver_stream = convert_channel_data(
-            channel_data=mattermost_data["channel"],
-            user_data_map=username_to_user,
-            subscriber_handler=subscriber_handler,
-            stream_id_mapper=stream_id_mapper,
-            user_id_mapper=user_id_mapper,
-            realm_id=3,
-            team_name=team_name,
-        )
+        with patch(
+            "zerver.data_import.mattermost.MATTERMOST_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME",
+            "Gryffindor common room",
+        ):
+            zerver_stream = convert_channel_data(
+                realm=mock_realm_dict,
+                channel_data=mattermost_data["channel"],
+                user_data_map=username_to_user,
+                subscriber_handler=subscriber_handler,
+                stream_id_mapper=stream_id_mapper,
+                user_id_mapper=user_id_mapper,
+                realm_id=3,
+                team_name=team_name,
+            )
 
         self.assert_length(zerver_stream, 3)
 
@@ -252,6 +260,11 @@ class MatterMostImporter(ZulipTestCase):
         self.assertEqual(zerver_stream[0]["rendered_description"], "")
         self.assertEqual(zerver_stream[0]["realm"], 3)
 
+        self.assertEqual(
+            zerver_realm[0]["zulip_update_announcements_stream"], zerver_stream[0]["id"]
+        )
+        self.assertEqual(zerver_realm[0]["new_stream_announcements_stream"], zerver_stream[0]["id"])
+
         self.assertEqual(zerver_stream[1]["name"], "Gryffindor quidditch team")
         self.assertEqual(zerver_stream[1]["invite_only"], False)
         self.assertEqual(
@@ -293,7 +306,9 @@ class MatterMostImporter(ZulipTestCase):
 
         # Converting channel data when a user's `teams` value is `null`.
         username_to_user["ron"].update(teams=None)
+        mock_realm_dict = dict(zerver_realm=[dict()])
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             channel_data=mattermost_data["channel"],
             user_data_map=username_to_user,
             subscriber_handler=subscriber_handler,
@@ -320,7 +335,9 @@ class MatterMostImporter(ZulipTestCase):
         )
 
         team_name = "slytherin"
+        mock_realm_dict = dict(zerver_realm=[dict()])
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             channel_data=mattermost_data["channel"],
             user_data_map=username_to_user,
             subscriber_handler=subscriber_handler,

zerver/tests/test_rocketchat_importer.py

@@ -258,6 +258,8 @@ class RocketChatImporter(ZulipTestCase):
         fixture_dir_name = self.fixture_file_name("", "rocketchat_fixtures")
         rocketchat_data = rocketchat_data_to_dict(fixture_dir_name)
 
+        mock_realm_dict: ZerverFieldsT = dict(zerver_realm=[dict()])
+        zerver_realm = mock_realm_dict["zerver_realm"]
         realm_id = 3
         stream_id_mapper = IdMapper[str]()
 
@@ -280,6 +282,7 @@ class RocketChatImporter(ZulipTestCase):
             )
 
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             room_id_to_room_map=room_id_to_room_map,
             team_id_to_team_map=team_id_to_team_map,
             stream_id_mapper=stream_id_mapper,
@@ -298,6 +301,11 @@ class RocketChatImporter(ZulipTestCase):
         self.assertEqual(zerver_stream[0]["stream_post_policy"], 1)
         self.assertEqual(zerver_stream[0]["realm"], realm_id)
 
+        self.assertEqual(
+            zerver_realm[0]["zulip_update_announcements_stream"], zerver_stream[0]["id"]
+        )
+        self.assertEqual(zerver_realm[0]["new_stream_announcements_stream"], zerver_stream[0]["id"])
+
         # Private stream
         self.assertEqual(zerver_stream[1]["name"], "random")
         self.assertEqual(zerver_stream[1]["invite_only"], True)
@@ -328,6 +336,7 @@ class RocketChatImporter(ZulipTestCase):
         fixture_dir_name = self.fixture_file_name("", "rocketchat_fixtures")
         rocketchat_data = rocketchat_data_to_dict(fixture_dir_name)
 
+        mock_realm_dict: ZerverFieldsT = dict(zerver_realm=[dict()])
         realm_id = 3
         domain_name = "zulip.com"
 
@@ -365,6 +374,7 @@ class RocketChatImporter(ZulipTestCase):
             )
 
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             room_id_to_room_map=room_id_to_room_map,
             team_id_to_team_map=team_id_to_team_map,
             stream_id_mapper=stream_id_mapper,
@@ -413,6 +423,7 @@ class RocketChatImporter(ZulipTestCase):
         room_id_to_room_map[no_user_channel["_id"]] = no_user_channel
 
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             room_id_to_room_map=room_id_to_room_map,
             team_id_to_team_map=team_id_to_team_map,
             stream_id_mapper=stream_id_mapper,
@@ -537,6 +548,7 @@ class RocketChatImporter(ZulipTestCase):
         fixture_dir_name = self.fixture_file_name("", "rocketchat_fixtures")
         rocketchat_data = rocketchat_data_to_dict(fixture_dir_name)
 
+        mock_realm_dict: ZerverFieldsT = dict(zerver_realm=[dict()])
         realm_id = 3
         domain_name = "zulip.com"
 
@@ -575,6 +587,7 @@ class RocketChatImporter(ZulipTestCase):
             )
 
         zerver_stream = convert_channel_data(
+            realm=mock_realm_dict,
             room_id_to_room_map=room_id_to_room_map,
             team_id_to_team_map=team_id_to_team_map,
             stream_id_mapper=stream_id_mapper,

zerver/tests/test_slack_importer.py

@@ -927,8 +927,15 @@ class SlackImporter(ZulipTestCase):
         }
         zerver_userprofile = [{"id": 1}, {"id": 8}, {"id": 7}, {"id": 5}]
         realm_id = 3
+        realm: ZerverFieldsT = {"zerver_userpresence": [], "zerver_realm": [dict()]}
+        zerver_realm = realm["zerver_realm"]
 
-        with self.assertLogs(level="INFO"):
+        with (
+            self.assertLogs(level="INFO"),
+            mock.patch(
+                "zerver.data_import.slack.SLACK_DEFAULT_ANNOUNCEMENTS_CHANNEL_NAME", "random"
+            ),
+        ):
             (
                 realm,
                 added_channels,
@@ -938,7 +945,7 @@ class SlackImporter(ZulipTestCase):
             ) = channels_to_zerver_stream(
                 self.fixture_file_name("", "slack_fixtures"),
                 realm_id,
-                {"zerver_userpresence": []},
+                realm,
                 slack_user_id_to_zulip_user_id,
                 zerver_userprofile,
             )
@@ -1007,6 +1014,11 @@ class SlackImporter(ZulipTestCase):
         self.assertEqual(zerver_stream[0]["realm"], realm_id)
         self.assertEqual(zerver_stream[2]["id"], test_added_channels[zerver_stream[2]["name"]][1])
 
+        self.assertEqual(
+            zerver_realm[0]["zulip_update_announcements_stream"], zerver_stream[0]["id"]
+        )
+        self.assertEqual(zerver_realm[0]["new_stream_announcements_stream"], zerver_stream[0]["id"])
+
         self.assertEqual(self.get_set(realm["zerver_huddle"], "id"), {0, 1, 2})
         self.assertEqual(realm["zerver_userpresence"], [])