notifications: Move user group mentions helpers together.

This refactored `get_mentioned_user_group_name` from
`zerver/lib/email_notifications.py` to
`zerver/lib/notification_data.py` just after
`get_user_group_mentions_data` to indicate the logical
similarity between them.

Signed-off-by: Zixuan James Li <359101898@qq.com>

zerver/lib/email_notifications.py

@@ -1,7 +1,6 @@
 # See https://zulip.readthedocs.io/en/latest/subsystems/notifications.html
 
 import logging
-import math
 import re
 from collections import defaultdict
 from datetime import timedelta
@@ -23,6 +22,7 @@ from confirmation.models import one_click_unsubscribe_link
 from zerver.decorator import statsd_increment
 from zerver.lib.markdown.fenced_code import FENCE_RE
 from zerver.lib.message import bulk_access_messages
+from zerver.lib.notification_data import get_mentioned_user_group_name
 from zerver.lib.queue import queue_json_publish
 from zerver.lib.send_email import FromAddress, send_future_email
 from zerver.lib.types import DisplayRecipientT
@@ -32,12 +32,10 @@ from zerver.lib.url_encoding import (
     stream_narrow_url,
     topic_narrow_url,
 )
-from zerver.lib.user_groups import get_user_group_direct_member_ids
 from zerver.models import (
     Message,
     Recipient,
     Stream,
-    UserGroup,
     UserMessage,
     UserProfile,
     get_context_for_message,
@@ -344,45 +342,6 @@ def get_narrow_url(
         return topic_narrow_url(user_profile.realm, stream, message.topic_name())
 
 
-def get_mentioned_user_group_name(
-    messages: List[Dict[str, Any]], user_profile: UserProfile
-) -> Optional[str]:
-    """Returns the user group name to display in the email notification
-    if user group(s) are mentioned.
-
-    This implements the same algorithm as get_user_group_mentions_data
-    in zerver/lib/notification_data.py, but we're passed a list of
-    messages instead.
-    """
-    for message in messages:
-        if message["mentioned_user_group_id"] is None and message["trigger"] == "mentioned":
-            # The user has also been personally mentioned, so that gets prioritized.
-            return None
-
-    # These IDs are those of the smallest user groups mentioned in each message.
-    mentioned_user_group_ids = [
-        message["mentioned_user_group_id"]
-        for message in messages
-        if message["mentioned_user_group_id"] is not None
-    ]
-
-    # We now want to calculate the name of the smallest user group mentioned among
-    # all these messages.
-    smallest_user_group_size = math.inf
-    smallest_user_group_name = None
-    for user_group_id in mentioned_user_group_ids:
-        current_user_group = UserGroup.objects.get(id=user_group_id, realm=user_profile.realm)
-        current_user_group_size = len(get_user_group_direct_member_ids(current_user_group))
-
-        if current_user_group_size < smallest_user_group_size:
-            # If multiple user groups are mentioned, we prefer the
-            # user group with the least members.
-            smallest_user_group_size = current_user_group_size
-            smallest_user_group_name = current_user_group.name
-
-    return smallest_user_group_name
-
-
 def message_content_allowed_in_missedmessage_emails(user_profile: UserProfile) -> bool:
     return (
         user_profile.realm.message_content_allowed_in_email_notifications

zerver/lib/notification_data.py

@@ -1,8 +1,10 @@
+import math
 from dataclasses import dataclass
-from typing import Collection, Dict, List, Optional, Set
+from typing import Any, Collection, Dict, List, Optional, Set
 
 from zerver.lib.mention import MentionData
-from zerver.models import NotificationTriggers
+from zerver.lib.user_groups import get_user_group_direct_member_ids
+from zerver.models import NotificationTriggers, UserGroup, UserProfile
 
 
 @dataclass
@@ -187,3 +189,42 @@ def get_user_group_mentions_data(
                 mentioned_user_groups_map[member_id] = group_id
 
     return mentioned_user_groups_map
+
+
+def get_mentioned_user_group_name(
+    messages: List[Dict[str, Any]], user_profile: UserProfile
+) -> Optional[str]:
+    """Returns the user group name to display in the email notification
+    if user group(s) are mentioned.
+
+    This implements the same algorithm as get_user_group_mentions_data
+    in zerver/lib/notification_data.py, but we're passed a list of
+    messages instead.
+    """
+    for message in messages:
+        if message["mentioned_user_group_id"] is None and message["trigger"] == "mentioned":
+            # The user has also been personally mentioned, so that gets prioritized.
+            return None
+
+    # These IDs are those of the smallest user groups mentioned in each message.
+    mentioned_user_group_ids = [
+        message["mentioned_user_group_id"]
+        for message in messages
+        if message["mentioned_user_group_id"] is not None
+    ]
+
+    # We now want to calculate the name of the smallest user group mentioned among
+    # all these messages.
+    smallest_user_group_size = math.inf
+    smallest_user_group_name = None
+    for user_group_id in mentioned_user_group_ids:
+        current_user_group = UserGroup.objects.get(id=user_group_id, realm=user_profile.realm)
+        current_user_group_size = len(get_user_group_direct_member_ids(current_user_group))
+
+        if current_user_group_size < smallest_user_group_size:
+            # If multiple user groups are mentioned, we prefer the
+            # user group with the least members.
+            smallest_user_group_size = current_user_group_size
+            smallest_user_group_name = current_user_group.name
+
+    return smallest_user_group_name