From 7252861785a604e85a9970e698126367cd0ab55c Mon Sep 17 00:00:00 2001
From: Steve Howell <showell@zulipchat.com>
Date: Thu, 1 Nov 2018 17:06:55 +0000
Subject: [PATCH] Extract filter_by_topic_name_via_message.

---
 zerver/lib/actions.py | 6 +++++-
 zerver/lib/topic.py   | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index 23fdc360d9..ffe976d54a 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -57,6 +57,7 @@ from zerver.lib.stream_subscription import (
 from zerver.lib.stream_topic import StreamTopicTarget
 from zerver.lib.topic import (
     filter_by_exact_message_topic,
+    filter_by_topic_name_via_message,
 )
 from zerver.lib.topic_mutes import (
     get_topic_mutes,
@@ -3652,7 +3653,10 @@ def do_mark_stream_messages_as_read(user_profile: UserProfile,
     msgs = msgs.filter(message__recipient=recipient)
 
     if topic_name:
-        msgs = msgs.filter(message__subject__iexact=topic_name)
+        msgs = filter_by_topic_name_via_message(
+            query=msgs,
+            topic_name=topic_name,
+        )
 
     msgs = msgs.extra(
         where=[UserMessage.where_unread()]
diff --git a/zerver/lib/topic.py b/zerver/lib/topic.py
index e05d794d7d..539777e6a1 100644
--- a/zerver/lib/topic.py
+++ b/zerver/lib/topic.py
@@ -13,6 +13,9 @@ def filter_by_exact_message_topic(query: QuerySet, message: Message) -> QuerySet
     topic_name = message.topic_name()
     return query.filter(subject=topic_name)
 
+def filter_by_topic_name_via_message(query: QuerySet, topic_name: str) -> QuerySet:
+    return query.filter(message__subject__iexact=topic_name)
+
 def generate_topic_history_from_db_rows(rows: List[Tuple[str, int]]) -> List[Dict[str, Any]]:
     canonical_topic_names = {}  # type: Dict[str, Tuple[int, str]]