From f8637ed61602bbaf19b57321d6d3402ddf36b152 Mon Sep 17 00:00:00 2001
From: Sam <sam.saffron@gmail.com>
Date: Thu, 5 Apr 2018 17:17:31 +1000
Subject: [PATCH] FIX: if a message is *partially* archived consider it not
 archived

---
 app/models/topic.rb       | 34 +++++++++++++++++++++++-----------
 spec/models/topic_spec.rb |  9 +++++++++
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/app/models/topic.rb b/app/models/topic.rb
index 7fbd711b3f1..abc0f5f2701 100644
--- a/app/models/topic.rb
+++ b/app/models/topic.rb
@@ -1168,19 +1168,31 @@ SQL
   def message_archived?(user)
     return false unless user && user.id
 
-    sql = <<SQL
-SELECT 1 FROM topic_allowed_groups tg
-JOIN group_archived_messages gm
-      ON gm.topic_id = tg.topic_id AND
-         gm.group_id = tg.group_id
-  WHERE tg.group_id IN (SELECT g.group_id FROM group_users g WHERE g.user_id = :user_id)
-    AND tg.topic_id = :topic_id
+    # tricky query but this checks to see if message is archived for ALL groups you belong to
+    # OR if you have it archived as a user explicitly
 
-UNION ALL
+    sql = <<~SQL
+    SELECT 1
+    WHERE
+      (
+      SELECT count(*) FROM topic_allowed_groups tg
+      JOIN group_archived_messages gm
+            ON gm.topic_id = tg.topic_id AND
+               gm.group_id = tg.group_id
+        WHERE tg.group_id IN (SELECT g.group_id FROM group_users g WHERE g.user_id = :user_id)
+          AND tg.topic_id = :topic_id
+      ) =
+      (
+        SELECT case when count(*) = 0 then -1 else count(*) end FROM topic_allowed_groups tg
+        WHERE tg.group_id IN (SELECT g.group_id FROM group_users g WHERE g.user_id = :user_id)
+          AND tg.topic_id = :topic_id
+      )
 
-SELECT 1 FROM topic_allowed_users tu
-JOIN user_archived_messages um ON um.user_id = tu.user_id AND um.topic_id = tu.topic_id
-WHERE tu.user_id = :user_id AND tu.topic_id = :topic_id
+      UNION ALL
+
+      SELECT 1 FROM topic_allowed_users tu
+      JOIN user_archived_messages um ON um.user_id = tu.user_id AND um.topic_id = tu.topic_id
+      WHERE tu.user_id = :user_id AND tu.topic_id = :topic_id
 SQL
 
     User.exec_sql(sql, user_id: user.id, topic_id: id).to_a.length > 0
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index a88441bb755..6a17b19bec7 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -1975,12 +1975,21 @@ describe Topic do
     expect(topic.message_archived?(user)).to eq(false)
 
     group = Fabricate(:group)
+    group2 = Fabricate(:group)
+
     group.add(user)
 
     TopicAllowedGroup.create!(topic_id: topic.id, group_id: group.id)
+    TopicAllowedGroup.create!(topic_id: topic.id, group_id: group2.id)
     GroupArchivedMessage.create!(topic_id: topic.id, group_id: group.id)
 
     expect(topic.message_archived?(user)).to eq(true)
+
+    # here is a pickle, we add another group, make the user a
+    # member of that new group... now this message is not properly archived
+    # for the user any more
+    group2.add(user)
+    expect(topic.message_archived?(user)).to eq(false)
   end
 
   it 'will trigger :topic_status_updated' do