zulip_updates: Send an introductory message before the first update.

To help users focus on the onboarding experience, we no longer
send the introductory "Zulip updates" message as a part of
onboarding.

Now, we send the introductory message just before the first
update message.

Fixes #30053.

zerver/lib/onboarding.py

@@ -359,21 +359,6 @@ This **greetings** topic is a great place to say “hi” :wave: to your teammat
 :point_right: Click on this message to start a new message in the same conversation.
 """)
 
-    content_of_zulip_update_announcements_topic_name = (
-        _("""
-Welcome! To help you learn about new features and configuration options,
-this topic will receive messages about important changes in Zulip.
-
-You can read these update messages whenever it's convenient, or
-[mute]({mute_topic_help_url}) this topic if you are not interested.
-If your organization does not want to receive these announcements,
-they can be disabled. [Learn more]({zulip_update_announcements_help_url}).
-        """)
-    ).format(
-        zulip_update_announcements_help_url="/help/configure-automated-notices#zulip-update-announcements",
-        mute_topic_help_url="/help/mute-a-topic",
-    )
-
     welcome_messages: List[Dict[str, str]] = []
 
     # Messages added to the "welcome messages" list last will be most
@@ -383,15 +368,6 @@ they can be disabled. [Learn more]({zulip_update_announcements_help_url}).
     #
     # Initial messages are configured below.
 
-    # Zulip updates system advertisement.
-    welcome_messages += [
-        {
-            "channel_name": str(Realm.DEFAULT_NOTIFICATION_STREAM_NAME),
-            "topic_name": str(Realm.ZULIP_UPDATE_ANNOUNCEMENTS_TOPIC_NAME),
-            "content": content_of_zulip_update_announcements_topic_name,
-        },
-    ]
-
     # Advertising moving messages.
     welcome_messages += [
         {

zerver/lib/zulip_update_announcements.py

@@ -14,6 +14,7 @@ from zerver.actions.message_send import (
     internal_prep_stream_message,
 )
 from zerver.lib.message import SendMessageRequest, remove_single_newlines
+from zerver.lib.topic import messages_for_topic
 from zerver.models.realm_audit_logs import RealmAuditLog
 from zerver.models.realms import Realm
 from zerver.models.users import UserProfile, get_system_bot
@@ -264,11 +265,47 @@ def send_zulip_update_announcements(
             ):
                 continue
 
-            messages = internal_prep_zulip_update_announcements_stream_messages(
-                current_level=realm_zulip_update_announcements_level,
-                latest_level=latest_zulip_update_announcements_level,
-                sender=sender,
-                realm=realm,
+            # Send an introductory message just before the first update message.
+            with override_language(realm.default_language):
+                topic_name = str(realm.ZULIP_UPDATE_ANNOUNCEMENTS_TOPIC_NAME)
+
+            stream = realm.zulip_update_announcements_stream
+            assert stream.recipient_id is not None
+            topic_has_messages = messages_for_topic(
+                realm.id, stream.recipient_id, topic_name
+            ).exists()
+
+            if not topic_has_messages:
+                content_of_introductory_message = (
+                    """
+To help you learn about new features and configuration options,
+this topic will receive messages about important changes in Zulip.
+
+You can read these update messages whenever it's convenient, or
+[mute]({mute_topic_help_url}) this topic if you are not interested.
+If your organization does not want to receive these announcements,
+they can be disabled. [Learn more]({zulip_update_announcements_help_url}).
+"""
+                ).format(
+                    zulip_update_announcements_help_url="/help/configure-automated-notices#zulip-update-announcements",
+                    mute_topic_help_url="/help/mute-a-topic",
+                )
+                messages = [
+                    internal_prep_stream_message(
+                        sender,
+                        stream,
+                        topic_name,
+                        remove_single_newlines(content_of_introductory_message),
+                    )
+                ]
+
+            messages.extend(
+                internal_prep_zulip_update_announcements_stream_messages(
+                    current_level=realm_zulip_update_announcements_level,
+                    latest_level=latest_zulip_update_announcements_level,
+                    sender=sender,
+                    realm=realm,
+                )
             )
 
             new_zulip_update_announcements_level = latest_zulip_update_announcements_level

zerver/tests/test_signup.py

@@ -1305,7 +1305,7 @@ class RealmCreationTest(ZulipTestCase):
 
         # Check welcome messages
         for stream_name, text, message_count in [
-            (str(Realm.DEFAULT_NOTIFICATION_STREAM_NAME), "learn about new features", 3),
+            (str(Realm.DEFAULT_NOTIFICATION_STREAM_NAME), "a great place to say “hi”", 2),
             (str(Realm.ZULIP_SANDBOX_CHANNEL_NAME), "Use this topic to try out", 5),
         ]:
             stream = get_stream(stream_name, realm)

zerver/tests/test_zulip_update_announcements.py

@@ -122,9 +122,10 @@ class ZulipUpdateAnnouncementsTest(ZulipTestCase):
                 recipient__type_id=verona.id,
                 date_sent__gte=now + timedelta(days=10),
             ).order_by("id")
-            self.assert_length(stream_messages, 2)
-            self.assertEqual(stream_messages[0].content, "Announcement message 3.")
-            self.assertEqual(stream_messages[1].content, "Announcement message 4.")
+            self.assert_length(stream_messages, 3)
+            self.assertIn("To help you learn about new features", stream_messages[0].content)
+            self.assertEqual(stream_messages[1].content, "Announcement message 3.")
+            self.assertEqual(stream_messages[2].content, "Announcement message 4.")
             self.assertEqual(realm.zulip_update_announcements_level, 4)
 
     def test_send_zulip_update_announcements_with_stream_configured(self) -> None: