MM-29988 - Update exising Post APIs with collapsed threads (#16503)

api4/commands_test.go

@@ -30,7 +30,7 @@ func TestEchoCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1 := Client.Must(Client.GetPostsForChannel(channel1.Id, 0, 2, "")).(*model.PostList)
+	p1 := Client.Must(Client.GetPostsForChannel(channel1.Id, 0, 2, "", false)).(*model.PostList)
 	require.Len(t, p1.Order, 2, "Echo command failed to send")
 }
 
@@ -302,7 +302,7 @@ func TestMeCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1 := Client.Must(Client.GetPostsForChannel(channel.Id, 0, 2, "")).(*model.PostList)
+	p1 := Client.Must(Client.GetPostsForChannel(channel.Id, 0, 2, "", false)).(*model.PostList)
 	require.Len(t, p1.Order, 2, "Command failed to send")
 
 	pt := p1.Posts[p1.Order[0]].Type
@@ -391,7 +391,7 @@ func TestShrugCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1 := Client.Must(Client.GetPostsForChannel(channel.Id, 0, 2, "")).(*model.PostList)
+	p1 := Client.Must(Client.GetPostsForChannel(channel.Id, 0, 2, "", false)).(*model.PostList)
 	require.Len(t, p1.Order, 2, "Command failed to send")
 	require.Equal(t, `¯\\\_(ツ)\_/¯`, p1.Posts[p1.Order[0]].Message, "invalid shrug response")
 }

api4/post.go

@@ -158,7 +158,8 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 		}
 	}
 	skipFetchThreads := r.URL.Query().Get("skipFetchThreads") == "true"
-
+	collapsedThreads := r.URL.Query().Get("collapsedThreads") == "true"
+	collapsedThreadsExtended := r.URL.Query().Get("collapsedThreadsExtended") == "true"
 	channelId := c.Params.ChannelId
 	page := c.Params.Page
 	perPage := c.Params.PerPage
@@ -173,31 +174,31 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 	etag := ""
 
 	if since > 0 {
-		list, err = c.App.GetPostsSince(model.GetPostsSinceOptions{ChannelId: channelId, Time: since, SkipFetchThreads: skipFetchThreads})
+		list, err = c.App.GetPostsSince(model.GetPostsSinceOptions{ChannelId: channelId, Time: since, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended})
 	} else if len(afterPost) > 0 {
-		etag = c.App.GetPostsEtag(channelId)
+		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
 		if c.HandleEtag(etag, "Get Posts After", w, r) {
 			return
 		}
 
-		list, err = c.App.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: afterPost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads})
+		list, err = c.App.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: afterPost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads})
 	} else if len(beforePost) > 0 {
-		etag = c.App.GetPostsEtag(channelId)
+		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
 		if c.HandleEtag(etag, "Get Posts Before", w, r) {
 			return
 		}
 
-		list, err = c.App.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: beforePost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads})
+		list, err = c.App.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: beforePost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended})
 	} else {
-		etag = c.App.GetPostsEtag(channelId)
+		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
 		if c.HandleEtag(etag, "Get Posts", w, r) {
 			return
 		}
 
-		list, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads})
+		list, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended})
 	}
 
 	if err != nil {
@@ -239,7 +240,10 @@ func getPostsForChannelAroundLastUnread(c *Context, w http.ResponseWriter, r *ht
 	}
 
 	skipFetchThreads := r.URL.Query().Get("skipFetchThreads") == "true"
-	postList, err := c.App.GetPostsForChannelAroundLastUnread(channelId, userId, c.Params.LimitBefore, c.Params.LimitAfter, skipFetchThreads)
+	collapsedThreads := r.URL.Query().Get("collapsedThreads") == "true"
+	collapsedThreadsExtended := r.URL.Query().Get("collapsedThreadsExtended") == "true"
+
+	postList, err := c.App.GetPostsForChannelAroundLastUnread(channelId, userId, c.Params.LimitBefore, c.Params.LimitAfter, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	if err != nil {
 		c.Err = err
 		return
@@ -247,13 +251,13 @@ func getPostsForChannelAroundLastUnread(c *Context, w http.ResponseWriter, r *ht
 
 	etag := ""
 	if len(postList.Order) == 0 {
-		etag = c.App.GetPostsEtag(channelId)
+		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
 		if c.HandleEtag(etag, "Get Posts", w, r) {
 			return
 		}
 
-		postList, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: app.PageDefault, PerPage: c.Params.LimitBefore, SkipFetchThreads: skipFetchThreads})
+		postList, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: app.PageDefault, PerPage: c.Params.LimitBefore, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended})
 		if err != nil {
 			c.Err = err
 			return
@@ -412,7 +416,9 @@ func getPostThread(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	skipFetchThreads := r.URL.Query().Get("skipFetchThreads") == "true"
-	list, err := c.App.GetPostThread(c.Params.PostId, skipFetchThreads)
+	collapsedThreads := r.URL.Query().Get("collapsedThreads") == "true"
+	collapsedThreadsExtended := r.URL.Query().Get("collapsedThreadsExtended") == "true"
+	list, err := c.App.GetPostThread(c.Params.PostId, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	if err != nil {
 		c.Err = err
 		return

api4/post_test.go

@@ -389,7 +389,7 @@ func testCreatePostWithOutgoingHook(
 
 	if commentPostType {
 		time.Sleep(time.Millisecond * 100)
-		postList, resp := th.SystemAdminClient.GetPostThread(post.Id, "")
+		postList, resp := th.SystemAdminClient.GetPostThread(post.Id, "", false)
 		CheckNoError(t, resp)
 		require.Equal(t, post.Id, postList.Order[0], "wrong order")
 
@@ -1052,17 +1052,17 @@ func TestGetPostsForChannel(t *testing.T) {
 	post4 := th.CreatePost()
 
 	th.TestForAllClients(t, func(t *testing.T, c *model.Client4) {
-		posts, resp := c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "")
+		posts, resp := c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false)
 		CheckNoError(t, resp)
 		require.Equal(t, post4.Id, posts.Order[0], "wrong order")
 		require.Equal(t, post3.Id, posts.Order[1], "wrong order")
 		require.Equal(t, post2.Id, posts.Order[2], "wrong order")
 		require.Equal(t, post1.Id, posts.Order[3], "wrong order")
 
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, resp.Etag)
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, resp.Etag, false)
 		CheckEtag(t, posts, resp)
 
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 3, "wrong number returned")
 
@@ -1071,11 +1071,11 @@ func TestGetPostsForChannel(t *testing.T) {
 		_, ok = posts.Posts[post1.Id]
 		require.True(t, ok, "missing root post")
 
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 1, 1, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 1, 1, "", false)
 		CheckNoError(t, resp)
 		require.Equal(t, post3.Id, posts.Order[0], "wrong order")
 
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 10000, 10000, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 10000, 10000, "", false)
 		CheckNoError(t, resp)
 		require.Empty(t, posts.Order, "should be no posts")
 	})
@@ -1083,7 +1083,7 @@ func TestGetPostsForChannel(t *testing.T) {
 	post5 := th.CreatePost()
 
 	th.TestForAllClients(t, func(t *testing.T, c *model.Client4) {
-		posts, resp := c.GetPostsSince(th.BasicChannel.Id, since)
+		posts, resp := c.GetPostsSince(th.BasicChannel.Id, since, false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Posts, 2, "should return 2 posts")
 
@@ -1105,18 +1105,18 @@ func TestGetPostsForChannel(t *testing.T) {
 			require.True(t, f, "missing post")
 		}
 
-		_, resp = c.GetPostsForChannel("", 0, 60, "")
+		_, resp = c.GetPostsForChannel("", 0, 60, "", false)
 		CheckBadRequestStatus(t, resp)
 
-		_, resp = c.GetPostsForChannel("junk", 0, 60, "")
+		_, resp = c.GetPostsForChannel("junk", 0, 60, "", false)
 		CheckBadRequestStatus(t, resp)
 	})
 
-	_, resp := Client.GetPostsForChannel(model.NewId(), 0, 60, "")
+	_, resp := Client.GetPostsForChannel(model.NewId(), 0, 60, "", false)
 	CheckForbiddenStatus(t, resp)
 
 	Client.Logout()
-	_, resp = Client.GetPostsForChannel(model.NewId(), 0, 60, "")
+	_, resp = Client.GetPostsForChannel(model.NewId(), 0, 60, "", false)
 	CheckUnauthorizedStatus(t, resp)
 
 	// more tests for next_post_id, prev_post_id, and order
@@ -1131,11 +1131,11 @@ func TestGetPostsForChannel(t *testing.T) {
 	var posts *model.PostList
 	th.TestForAllClients(t, func(t *testing.T, c *model.Client4) {
 		// get the system post IDs posted before the created posts above
-		posts, resp = c.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "")
+		posts, resp = c.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
 		systemPostId1 := posts.Order[1]
 
 		// similar to '/posts'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 12, "expected 12 posts")
 		require.Equal(t, post10.Id, posts.Order[0], "posts not in order")
@@ -1144,7 +1144,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 		// similar to '/posts?per_page=3'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post10.Id, posts.Order[0], "posts not in order")
@@ -1153,7 +1153,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, post7.Id, posts.PrevPostId, "should return post7.Id as PrevPostId")
 
 		// similar to '/posts?per_page=3&page=1'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 1, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 1, 3, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post7.Id, posts.Order[0], "posts not in order")
@@ -1162,7 +1162,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, post4.Id, posts.PrevPostId, "should return post4.Id as PrevPostId")
 
 		// similar to '/posts?per_page=3&page=2'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 2, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 2, 3, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post4.Id, posts.Order[0], "posts not in order")
@@ -1171,7 +1171,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, post1.Id, posts.PrevPostId, "should return post1.Id as PrevPostId")
 
 		// similar to '/posts?per_page=3&page=3'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 3, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 3, 3, "", false)
 		CheckNoError(t, resp)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post1.Id, posts.Order[0], "posts not in order")
@@ -1180,7 +1180,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 		// similar to '/posts?per_page=3&page=4'
-		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 4, 3, "")
+		posts, resp = c.GetPostsForChannel(th.BasicChannel.Id, 4, 3, "", false)
 		CheckNoError(t, resp)
 		require.Empty(t, posts.Order, "should return 0 post")
 		require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1390,7 +1390,7 @@ func TestGetPostsBefore(t *testing.T) {
 	post4 := th.CreatePost()
 	post5 := th.CreatePost()
 
-	posts, resp := Client.GetPostsBefore(th.BasicChannel.Id, post3.Id, 0, 100, "")
+	posts, resp := Client.GetPostsBefore(th.BasicChannel.Id, post3.Id, 0, 100, "", false)
 	CheckNoError(t, resp)
 
 	found := make([]bool, 2)
@@ -1412,17 +1412,17 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, post3.Id, posts.NextPostId, "should match NextPostId")
 	require.Equal(t, "", posts.PrevPostId, "should match empty PrevPostId")
 
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post4.Id, 1, 1, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post4.Id, 1, 1, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 1, "too many posts returned")
 	require.Equal(t, post2.Id, posts.Order[0], "should match returned post")
 	require.Equal(t, post3.Id, posts.NextPostId, "should match NextPostId")
 	require.Equal(t, post1.Id, posts.PrevPostId, "should match PrevPostId")
 
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, "junk", 1, 1, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, "junk", 1, 1, "", false)
 	CheckBadRequestStatus(t, resp)
 
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 0, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 0, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post4.Id, posts.Order[0], "should match returned post")
@@ -1431,12 +1431,12 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, post1.Id, posts.PrevPostId, "should match PrevPostId")
 
 	// get the system post IDs posted before the created posts above
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
 	CheckNoError(t, resp)
 	systemPostId2 := posts.Order[0]
 	systemPostId1 := posts.Order[1]
 
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 1, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 1, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post1.Id, posts.Order[0], "should match returned post")
@@ -1454,7 +1454,7 @@ func TestGetPostsBefore(t *testing.T) {
 	th.CreatePost() // post10
 
 	// similar to '/posts?before=post9'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 60, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 10, "expected 10 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "posts not in order")
@@ -1463,7 +1463,7 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 	// similar to '/posts?before=post9&per_page=3'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "posts not in order")
@@ -1472,7 +1472,7 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, post5.Id, posts.PrevPostId, "should return post5.Id as PrevPostId")
 
 	// similar to '/posts?before=post9&per_page=3&page=1'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 1, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 1, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post5.Id, posts.Order[0], "posts not in order")
@@ -1481,7 +1481,7 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, post2.Id, posts.PrevPostId, "should return post2.Id as PrevPostId")
 
 	// similar to '/posts?before=post9&per_page=3&page=2'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 2, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 2, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post2.Id, posts.Order[0], "posts not in order")
@@ -1490,7 +1490,7 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, systemPostId1, posts.PrevPostId, "should return systemPostId1 as PrevPostId")
 
 	// similar to '/posts?before=post1&per_page=3'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 3, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 2, "expected 2 posts")
 	require.Equal(t, systemPostId2, posts.Order[0], "posts not in order")
@@ -1499,14 +1499,14 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 	// similar to '/posts?before=systemPostId1'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 0, 60, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, systemPostId1, posts.NextPostId, "should return systemPostId1 as NextPostId")
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 	// similar to '/posts?before=systemPostId1&per_page=60&page=1'
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 1, 60, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 1, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 posts")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1514,7 +1514,7 @@ func TestGetPostsBefore(t *testing.T) {
 
 	// similar to '/posts?before=non-existent-post'
 	nonExistentPostId := model.NewId()
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, nonExistentPostId, 0, 60, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, nonExistentPostId, posts.NextPostId, "should return nonExistentPostId as NextPostId")
@@ -1532,7 +1532,7 @@ func TestGetPostsAfter(t *testing.T) {
 	post4 := th.CreatePost()
 	post5 := th.CreatePost()
 
-	posts, resp := Client.GetPostsAfter(th.BasicChannel.Id, post3.Id, 0, 100, "")
+	posts, resp := Client.GetPostsAfter(th.BasicChannel.Id, post3.Id, 0, 100, "", false)
 	CheckNoError(t, resp)
 
 	found := make([]bool, 2)
@@ -1552,17 +1552,17 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, "", posts.NextPostId, "should match empty NextPostId")
 	require.Equal(t, post3.Id, posts.PrevPostId, "should match PrevPostId")
 
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 1, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 1, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 1, "too many posts returned")
 	require.Equal(t, post4.Id, posts.Order[0], "should match returned post")
 	require.Equal(t, post5.Id, posts.NextPostId, "should match NextPostId")
 	require.Equal(t, post3.Id, posts.PrevPostId, "should match PrevPostId")
 
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, "junk", 1, 1, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, "junk", 1, 1, "", false)
 	CheckBadRequestStatus(t, resp)
 
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 3, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post4.Id, posts.Order[0], "should match returned post")
@@ -1570,7 +1570,7 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post5.Id, posts.NextPostId, "should match NextPostId")
 	require.Equal(t, post1.Id, posts.PrevPostId, "should match PrevPostId")
 
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 1, 3, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 1, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Posts, 1, "should match length of posts returned")
 	require.Equal(t, post5.Id, posts.Order[0], "should match returned post")
@@ -1586,7 +1586,7 @@ func TestGetPostsAfter(t *testing.T) {
 	post10 := th.CreatePost()
 
 	// similar to '/posts?after=post2'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 60, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 8, "expected 8 posts")
 	require.Equal(t, post10.Id, posts.Order[0], "should match order")
@@ -1595,7 +1595,7 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post2.Id, posts.PrevPostId, "should return post2.Id as PrevPostId")
 
 	// similar to '/posts?after=post2&per_page=3'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 3, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post5.Id, posts.Order[0], "should match order")
@@ -1604,7 +1604,7 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post2.Id, posts.PrevPostId, "should return post2.Id as PrevPostId")
 
 	// similar to '/posts?after=post2&per_page=3&page=1'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 3, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "should match order")
@@ -1613,7 +1613,7 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post5.Id, posts.PrevPostId, "should return post5.Id as PrevPostId")
 
 	// similar to '/posts?after=post2&per_page=3&page=2'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 2, 3, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 2, 3, "", false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 2, "expected 2 posts")
 	require.Equal(t, post10.Id, posts.Order[0], "should match order")
@@ -1622,14 +1622,14 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post8.Id, posts.PrevPostId, "should return post8.Id as PrevPostId")
 
 	// similar to '/posts?after=post10'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 0, 60, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
 	require.Equal(t, post10.Id, posts.PrevPostId, "should return post10.Id as PrevPostId")
 
 	// similar to '/posts?after=post10&page=1'
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 1, 60, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 1, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1637,7 +1637,7 @@ func TestGetPostsAfter(t *testing.T) {
 
 	// similar to '/posts?after=non-existent-post'
 	nonExistentPostId := model.NewId()
-	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, nonExistentPostId, 0, 60, "")
+	posts, resp = Client.GetPostsAfter(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false)
 	CheckNoError(t, resp)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1720,13 +1720,13 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	}
 
 	// Setting limit_after to zero should fail with a 400 BadRequest.
-	posts, resp := Client.GetPostsAroundLastUnread(userId, channelId, 20, 0)
+	posts, resp := Client.GetPostsAroundLastUnread(userId, channelId, 20, 0, false)
 	require.Error(t, resp.Error)
 	require.Equal(t, "api.context.invalid_url_param.app_error", resp.Error.Id)
 	require.Equal(t, http.StatusBadRequest, resp.StatusCode)
 
 	// All returned posts are all read by the user, since it's created by the user itself.
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 20, 20)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 20, 20, false)
 	CheckNoError(t, resp)
 	require.Len(t, posts.Order, 12, "Should return 12 posts only since there's no unread post")
 
@@ -1739,13 +1739,13 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 20, 20)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 20, 20, false)
 	CheckNoError(t, resp)
 
 	require.Len(t, posts.Order, 12, "Should return 12 posts only since there's no unread post")
 
 	// get the first system post generated before the created posts above
-	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "")
+	posts, resp = Client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
 	CheckNoError(t, resp)
 	systemPost0 := posts.Posts[posts.Order[0]]
 	postIdNames[systemPost0.Id] = "system post 0"
@@ -1760,7 +1760,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3, false)
 	CheckNoError(t, resp)
 
 	assertPostList(t, &model.PostList{
@@ -1784,7 +1784,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3, false)
 	CheckNoError(t, resp)
 
 	assertPostList(t, &model.PostList{
@@ -1811,7 +1811,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3, false)
 	CheckNoError(t, resp)
 
 	assertPostList(t, &model.PostList{
@@ -1836,7 +1836,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 3, 3, false)
 	CheckNoError(t, resp)
 
 	assertPostList(t, &model.PostList{
@@ -1876,7 +1876,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	require.Nil(t, err)
 	th.App.Srv().Store.Post().InvalidateLastPostTimeCache(channelId)
 
-	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 1, 2)
+	posts, resp = Client.GetPostsAroundLastUnread(userId, channelId, 1, 2, false)
 	CheckNoError(t, resp)
 
 	assertPostList(t, &model.PostList{
@@ -2051,11 +2051,11 @@ func TestGetPostThread(t *testing.T) {
 	post := &model.Post{ChannelId: th.BasicChannel.Id, Message: "zz" + model.NewId() + "a", RootId: th.BasicPost.Id}
 	post, _ = Client.CreatePost(post)
 
-	list, resp := Client.GetPostThread(th.BasicPost.Id, "")
+	list, resp := Client.GetPostThread(th.BasicPost.Id, "", false)
 	CheckNoError(t, resp)
 
 	var list2 *model.PostList
-	list2, resp = Client.GetPostThread(th.BasicPost.Id, resp.Etag)
+	list2, resp = Client.GetPostThread(th.BasicPost.Id, resp.Etag, false)
 	CheckEtag(t, list2, resp)
 	require.Equal(t, th.BasicPost.Id, list.Order[0], "wrong order")
 
@@ -2065,34 +2065,34 @@ func TestGetPostThread(t *testing.T) {
 	_, ok = list.Posts[post.Id]
 	require.True(t, ok, "should have had post")
 
-	_, resp = Client.GetPostThread("junk", "")
+	_, resp = Client.GetPostThread("junk", "", false)
 	CheckBadRequestStatus(t, resp)
 
-	_, resp = Client.GetPostThread(model.NewId(), "")
+	_, resp = Client.GetPostThread(model.NewId(), "", false)
 	CheckNotFoundStatus(t, resp)
 
 	Client.RemoveUserFromChannel(th.BasicChannel.Id, th.BasicUser.Id)
 
 	// Channel is public, should be able to read post
-	_, resp = Client.GetPostThread(th.BasicPost.Id, "")
+	_, resp = Client.GetPostThread(th.BasicPost.Id, "", false)
 	CheckNoError(t, resp)
 
 	privatePost := th.CreatePostWithClient(Client, th.BasicPrivateChannel)
 
-	_, resp = Client.GetPostThread(privatePost.Id, "")
+	_, resp = Client.GetPostThread(privatePost.Id, "", false)
 	CheckNoError(t, resp)
 
 	Client.RemoveUserFromChannel(th.BasicPrivateChannel.Id, th.BasicUser.Id)
 
 	// Channel is private, should not be able to read post
-	_, resp = Client.GetPostThread(privatePost.Id, "")
+	_, resp = Client.GetPostThread(privatePost.Id, "", false)
 	CheckForbiddenStatus(t, resp)
 
 	Client.Logout()
-	_, resp = Client.GetPostThread(model.NewId(), "")
+	_, resp = Client.GetPostThread(model.NewId(), "", false)
 	CheckUnauthorizedStatus(t, resp)
 
-	_, resp = th.SystemAdminClient.GetPostThread(th.BasicPost.Id, "")
+	_, resp = th.SystemAdminClient.GetPostThread(th.BasicPost.Id, "", false)
 	CheckNoError(t, resp)
 }
 

api4/team_test.go

@@ -2704,7 +2704,7 @@ func TestImportTeam(t *testing.T) {
 		CheckNoError(t, resp)
 		require.Equal(t, importedChannel.Name, "general", "names did not match expected: general")
 
-		posts, resp := th.SystemAdminClient.GetPostsForChannel(importedChannel.Id, 0, 60, "")
+		posts, resp := th.SystemAdminClient.GetPostsForChannel(importedChannel.Id, 0, 60, "", false)
 		CheckNoError(t, resp)
 		require.Equal(t, posts.Posts[posts.Order[3]].Message, "This is a test post to test the import process", "missing posts in the import process")
 	})

app/app_iface.go

@@ -631,13 +631,13 @@ type AppIface interface {
 	GetPostAfterTime(channelId string, time int64) (*model.Post, *model.AppError)
 	GetPostIdAfterTime(channelId string, time int64) (string, *model.AppError)
 	GetPostIdBeforeTime(channelId string, time int64) (string, *model.AppError)
-	GetPostThread(postId string, skipFetchThreads bool) (*model.PostList, *model.AppError)
+	GetPostThread(postId string, skipFetchThreads, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, *model.AppError)
 	GetPosts(channelId string, offset int, limit int) (*model.PostList, *model.AppError)
 	GetPostsAfterPost(options model.GetPostsOptions) (*model.PostList, *model.AppError)
 	GetPostsAroundPost(before bool, options model.GetPostsOptions) (*model.PostList, *model.AppError)
 	GetPostsBeforePost(options model.GetPostsOptions) (*model.PostList, *model.AppError)
-	GetPostsEtag(channelId string) string
+	GetPostsEtag(channelId string, collapsedThreads bool) string
-	GetPostsForChannelAroundLastUnread(channelId, userId string, limitBefore, limitAfter int, skipFetchThreads bool) (*model.PostList, *model.AppError)
+	GetPostsForChannelAroundLastUnread(channelId, userId string, limitBefore, limitAfter int, skipFetchThreads bool, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, *model.AppError)
 	GetPostsPage(options model.GetPostsOptions) (*model.PostList, *model.AppError)
 	GetPostsSince(options model.GetPostsSinceOptions) (*model.PostList, *model.AppError)
 	GetPreferenceByCategoryAndNameForUser(userId string, category string, preferenceName string) (*model.Preference, *model.AppError)

app/file.go

@@ -388,7 +388,7 @@ func (a *App) MigrateFilenamesToFileInfos(post *model.Post) []*model.FileInfo {
 	fileMigrationLock.Lock()
 	defer fileMigrationLock.Unlock()
 
-	result, nErr := a.Srv().Store.Post().Get(post.Id, false)
+	result, nErr := a.Srv().Store.Post().Get(post.Id, false, false, false)
 	if nErr != nil {
 		mlog.Error("Unable to get post when migrating post to use FileInfos", mlog.Err(nErr), mlog.String("post_id", post.Id))
 		return []*model.FileInfo{}

app/opentracing/opentracing_layer.go

@@ -7056,7 +7056,7 @@ func (a *OpenTracingAppLayer) GetPostIdBeforeTime(channelId string, time int64)
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) GetPostThread(postId string, skipFetchThreads bool) (*model.PostList, *model.AppError) {
+func (a *OpenTracingAppLayer) GetPostThread(postId string, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetPostThread")
 
@@ -7068,7 +7068,7 @@ func (a *OpenTracingAppLayer) GetPostThread(postId string, skipFetchThreads bool
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.GetPostThread(postId, skipFetchThreads)
+	resultVar0, resultVar1 := a.app.GetPostThread(postId, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))
@@ -7166,7 +7166,7 @@ func (a *OpenTracingAppLayer) GetPostsBeforePost(options model.GetPostsOptions)
 	return resultVar0, resultVar1
 }
 
-func (a *OpenTracingAppLayer) GetPostsEtag(channelId string) string {
+func (a *OpenTracingAppLayer) GetPostsEtag(channelId string, collapsedThreads bool) string {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetPostsEtag")
 
@@ -7178,12 +7178,12 @@ func (a *OpenTracingAppLayer) GetPostsEtag(channelId string) string {
 	}()
 
 	defer span.Finish()
-	resultVar0 := a.app.GetPostsEtag(channelId)
+	resultVar0 := a.app.GetPostsEtag(channelId, collapsedThreads)
 
 	return resultVar0
 }
 
-func (a *OpenTracingAppLayer) GetPostsForChannelAroundLastUnread(channelId string, userId string, limitBefore int, limitAfter int, skipFetchThreads bool) (*model.PostList, *model.AppError) {
+func (a *OpenTracingAppLayer) GetPostsForChannelAroundLastUnread(channelId string, userId string, limitBefore int, limitAfter int, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, *model.AppError) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetPostsForChannelAroundLastUnread")
 
@@ -7195,7 +7195,7 @@ func (a *OpenTracingAppLayer) GetPostsForChannelAroundLastUnread(channelId strin
 	}()
 
 	defer span.Finish()
-	resultVar0, resultVar1 := a.app.GetPostsForChannelAroundLastUnread(channelId, userId, limitBefore, limitAfter, skipFetchThreads)
+	resultVar0, resultVar1 := a.app.GetPostsForChannelAroundLastUnread(channelId, userId, limitBefore, limitAfter, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 
 	if resultVar1 != nil {
 		span.LogFields(spanlog.Error(resultVar1))

app/plugin_api.go

@@ -574,7 +574,7 @@ func (api *PluginAPI) DeletePost(postId string) *model.AppError {
 }
 
 func (api *PluginAPI) GetPostThread(postId string) (*model.PostList, *model.AppError) {
-	return api.app.GetPostThread(postId, false)
+	return api.app.GetPostThread(postId, false, false, false)
 }
 
 func (api *PluginAPI) GetPost(postId string) (*model.Post, *model.AppError) {

app/post.go

@@ -185,7 +185,7 @@ func (a *App) CreatePost(post *model.Post, channel *model.Channel, triggerWebhoo
 	if len(post.RootId) > 0 {
 		pchan = make(chan store.StoreResult, 1)
 		go func() {
-			r, pErr := a.Srv().Store.Post().Get(post.RootId, false)
+			r, pErr := a.Srv().Store.Post().Get(post.RootId, false, false, false)
 			pchan <- store.StoreResult{Data: r, NErr: pErr}
 			close(pchan)
 		}()
@@ -542,7 +542,7 @@ func (a *App) DeleteEphemeralPost(userId, postId string) {
 func (a *App) UpdatePost(post *model.Post, safeUpdate bool) (*model.Post, *model.AppError) {
 	post.SanitizeProps()
 
-	postLists, nErr := a.Srv().Store.Post().Get(post.Id, false)
+	postLists, nErr := a.Srv().Store.Post().Get(post.Id, false, false, false)
 	if nErr != nil {
 		var nfErr *store.ErrNotFound
 		var invErr *store.ErrInvalidInput
@@ -718,8 +718,8 @@ func (a *App) GetPosts(channelId string, offset int, limit int) (*model.PostList
 	return postList, nil
 }
 
-func (a *App) GetPostsEtag(channelId string) string {
+func (a *App) GetPostsEtag(channelId string, collapsedThreads bool) string {
-	return a.Srv().Store.Post().GetEtag(channelId, true)
+	return a.Srv().Store.Post().GetEtag(channelId, true, collapsedThreads)
 }
 
 func (a *App) GetPostsSince(options model.GetPostsSinceOptions) (*model.PostList, *model.AppError) {
@@ -746,8 +746,8 @@ func (a *App) GetSinglePost(postId string) (*model.Post, *model.AppError) {
 	return post, nil
 }
 
-func (a *App) GetPostThread(postId string, skipFetchThreads bool) (*model.PostList, *model.AppError) {
+func (a *App) GetPostThread(postId string, skipFetchThreads, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, *model.AppError) {
-	posts, err := a.Srv().Store.Post().Get(postId, skipFetchThreads)
+	posts, err := a.Srv().Store.Post().Get(postId, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	if err != nil {
 		var nfErr *store.ErrNotFound
 		var invErr *store.ErrInvalidInput
@@ -792,7 +792,7 @@ func (a *App) GetFlaggedPostsForChannel(userId, channelId string, offset int, li
 }
 
 func (a *App) GetPermalinkPost(postId string, userId string) (*model.PostList, *model.AppError) {
-	list, nErr := a.Srv().Store.Post().Get(postId, false)
+	list, nErr := a.Srv().Store.Post().Get(postId, false, false, false)
 	if nErr != nil {
 		var nfErr *store.ErrNotFound
 		var invErr *store.ErrInvalidInput
@@ -975,7 +975,7 @@ func (a *App) AddCursorIdsForPostList(originalList *model.PostList, afterPost, b
 	originalList.NextPostId = nextPostId
 	originalList.PrevPostId = prevPostId
 }
-func (a *App) GetPostsForChannelAroundLastUnread(channelId, userId string, limitBefore, limitAfter int, skipFetchThreads bool) (*model.PostList, *model.AppError) {
+func (a *App) GetPostsForChannelAroundLastUnread(channelId, userId string, limitBefore, limitAfter int, skipFetchThreads bool, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, *model.AppError) {
 	var member *model.ChannelMember
 	var err *model.AppError
 	if member, err = a.GetChannelMember(channelId, userId); err != nil {
@@ -991,7 +991,7 @@ func (a *App) GetPostsForChannelAroundLastUnread(channelId, userId string, limit
 		return model.NewPostList(), nil
 	}
 
-	postList, err := a.GetPostThread(lastUnreadPostId, skipFetchThreads)
+	postList, err := a.GetPostThread(lastUnreadPostId, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	if err != nil {
 		return nil, err
 	}
@@ -999,13 +999,13 @@ func (a *App) GetPostsForChannelAroundLastUnread(channelId, userId string, limit
 	// channel organically, those replies will be added below.
 	postList.Order = []string{lastUnreadPostId}
 
-	if postListBefore, err := a.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: lastUnreadPostId, Page: PageDefault, PerPage: limitBefore, SkipFetchThreads: skipFetchThreads}); err != nil {
+	if postListBefore, err := a.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: lastUnreadPostId, Page: PageDefault, PerPage: limitBefore, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended}); err != nil {
 		return nil, err
 	} else if postListBefore != nil {
 		postList.Extend(postListBefore)
 	}
 
-	if postListAfter, err := a.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: lastUnreadPostId, Page: PageDefault, PerPage: limitAfter - 1, SkipFetchThreads: skipFetchThreads}); err != nil {
+	if postListAfter, err := a.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: lastUnreadPostId, Page: PageDefault, PerPage: limitAfter - 1, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended}); err != nil {
 		return nil, err
 	} else if postListAfter != nil {
 		postList.Extend(postListAfter)
@@ -1434,7 +1434,7 @@ func (a *App) countMentionsFromPost(user *model.User, post *model.Post) (int, *m
 	// A mapping of thread root IDs to whether or not a post in that thread mentions the user
 	mentionedByThread := make(map[string]bool)
 
-	thread, err := a.GetPostThread(post.Id, false)
+	thread, err := a.GetPostThread(post.Id, false, false, false)
 	if err != nil {
 		return 0, err
 	}

app/post_test.go

@@ -1921,3 +1921,52 @@ func TestThreadMembership(t *testing.T) {
 		require.Len(t, memberships, 2)
 	})
 }
+
+func TestCollapsedThreadFetch(t *testing.T) {
+	th := Setup(t).InitBasic()
+	defer th.TearDown()
+	th.App.UpdateConfig(func(cfg *model.Config) {
+		*cfg.ServiceSettings.ThreadAutoFollow = true
+		*cfg.ServiceSettings.CollapsedThreads = model.COLLAPSED_THREADS_DEFAULT_ON
+	})
+	user1 := th.BasicUser
+	user2 := th.BasicUser2
+
+	t.Run("should only return root posts, enriched", func(t *testing.T) {
+		channel := th.CreateChannel(th.BasicTeam)
+		th.AddUserToChannel(user2, channel)
+		defer th.App.DeleteChannel(channel, user1.Id)
+
+		postRoot, err := th.App.CreatePost(&model.Post{
+			UserId:    user1.Id,
+			ChannelId: channel.Id,
+			Message:   "root post",
+		}, channel, false, true)
+		require.Nil(t, err)
+
+		_, err = th.App.CreatePost(&model.Post{
+			UserId:    user1.Id,
+			ChannelId: channel.Id,
+			RootId:    postRoot.Id,
+			Message:   fmt.Sprintf("@%s", user2.Username),
+		}, channel, false, true)
+		require.Nil(t, err)
+		thread, nErr := th.App.Srv().Store.Thread().Get(postRoot.Id)
+		require.Nil(t, nErr)
+		require.Len(t, thread.Participants, 2)
+		th.App.MarkChannelAsUnreadFromPost(postRoot.Id, user1.Id)
+		l, err := th.App.GetPostsForChannelAroundLastUnread(channel.Id, user1.Id, 10, 10, true, true, false)
+		require.Nil(t, err)
+		require.Len(t, l.Order, 1)
+		require.EqualValues(t, 1, l.Posts[postRoot.Id].ReplyCount)
+		require.EqualValues(t, []string{user1.Id, user2.Id}, []string{l.Posts[postRoot.Id].Participants[0].Id, l.Posts[postRoot.Id].Participants[1].Id})
+		require.Empty(t, l.Posts[postRoot.Id].Participants[0].Email)
+		require.NotZero(t, l.Posts[postRoot.Id].LastReplyAt)
+
+		// try extended fetch
+		l, err = th.App.GetPostsForChannelAroundLastUnread(channel.Id, user1.Id, 10, 10, true, true, true)
+		require.Nil(t, err)
+		require.Len(t, l.Order, 1)
+		require.NotEmpty(t, l.Posts[postRoot.Id].Participants[0].Email)
+	})
+}

config/client.go

@@ -135,6 +135,7 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 	props["CustomUrlSchemes"] = strings.Join(c.DisplaySettings.CustomUrlSchemes, ",")
 	props["IsDefaultMarketplace"] = strconv.FormatBool(*c.PluginSettings.MarketplaceUrl == model.PLUGIN_SETTINGS_DEFAULT_MARKETPLACE_URL)
 	props["ExperimentalSharedChannels"] = "false"
+	props["CollapsedThreads"] = *c.ServiceSettings.CollapsedThreads
 
 	if license != nil {
 		props["ExperimentalHideTownSquareinLHS"] = strconv.FormatBool(*c.TeamSettings.ExperimentalHideTownSquareinLHS)

model/client4.go

@@ -2903,8 +2903,12 @@ func (c *Client4) DeletePost(postId string) (bool, *Response) {
 }
 
 // GetPostThread gets a post with all the other posts in the same thread.
-func (c *Client4) GetPostThread(postId string, etag string) (*PostList, *Response) {
+func (c *Client4) GetPostThread(postId string, etag string, collapsedThreads bool) (*PostList, *Response) {
-	r, err := c.DoApiGet(c.GetPostRoute(postId)+"/thread", etag)
+	url := c.GetPostRoute(postId) + "/thread"
+	if collapsedThreads {
+		url += "?collapsedThreads=true"
+	}
+	r, err := c.DoApiGet(url, etag)
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)
 	}
@@ -2913,8 +2917,11 @@ func (c *Client4) GetPostThread(postId string, etag string) (*PostList, *Respons
 }
 
 // GetPostsForChannel gets a page of posts with an array for ordering for a channel.
-func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag string) (*PostList, *Response) {
+func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response) {
 	query := fmt.Sprintf("?page=%v&per_page=%v", page, perPage)
+	if collapsedThreads {
+		query += "&collapsedThreads=true"
+	}
 	r, err := c.DoApiGet(c.GetChannelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)
@@ -2965,8 +2972,11 @@ func (c *Client4) GetFlaggedPostsForUserInChannel(userId string, channelId strin
 }
 
 // GetPostsSince gets posts created after a specified time as Unix time in milliseconds.
-func (c *Client4) GetPostsSince(channelId string, time int64) (*PostList, *Response) {
+func (c *Client4) GetPostsSince(channelId string, time int64, collapsedThreads bool) (*PostList, *Response) {
 	query := fmt.Sprintf("?since=%v", time)
+	if collapsedThreads {
+		query += "&collapsedThreads=true"
+	}
 	r, err := c.DoApiGet(c.GetChannelRoute(channelId)+"/posts"+query, "")
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)
@@ -2976,8 +2986,11 @@ func (c *Client4) GetPostsSince(channelId string, time int64) (*PostList, *Respo
 }
 
 // GetPostsAfter gets a page of posts that were posted after the post provided.
-func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, etag string) (*PostList, *Response) {
+func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&after=%v", page, perPage, postId)
+	if collapsedThreads {
+		query += "&collapsedThreads=true"
+	}
 	r, err := c.DoApiGet(c.GetChannelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)
@@ -2987,8 +3000,11 @@ func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, eta
 }
 
 // GetPostsBefore gets a page of posts that were posted before the post provided.
-func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, etag string) (*PostList, *Response) {
+func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, etag string, collapsedThreads bool) (*PostList, *Response) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&before=%v", page, perPage, postId)
+	if collapsedThreads {
+		query += "&collapsedThreads=true"
+	}
 	r, err := c.DoApiGet(c.GetChannelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)
@@ -2998,8 +3014,11 @@ func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, et
 }
 
 // GetPostsAroundLastUnread gets a list of posts around last unread post by a user in a channel.
-func (c *Client4) GetPostsAroundLastUnread(userId, channelId string, limitBefore, limitAfter int) (*PostList, *Response) {
+func (c *Client4) GetPostsAroundLastUnread(userId, channelId string, limitBefore, limitAfter int, collapsedThreads bool) (*PostList, *Response) {
 	query := fmt.Sprintf("?limit_before=%v&limit_after=%v", limitBefore, limitAfter)
+	if collapsedThreads {
+		query += "&collapsedThreads=true"
+	}
 	r, err := c.DoApiGet(c.GetUserRoute(userId)+c.GetChannelRoute(channelId)+"/posts/unread"+query, "")
 	if err != nil {
 		return nil, BuildErrorResponse(r, err)

model/post.go

@@ -99,8 +99,10 @@ type Post struct {
 	HasReactions  bool            `json:"has_reactions,omitempty"`
 
 	// Transient data populated before sending a post to the client
-	ReplyCount int64         `json:"reply_count" db:"-"`
+	ReplyCount   int64         `json:"reply_count" db:"-"`
-	Metadata   *PostMetadata `json:"metadata,omitempty" db:"-"`
+	LastReplyAt  int64         `json:"last_reply_at" db:"-"`
+	Participants []*User       `json:"participants" db:"-"`
+	Metadata     *PostMetadata `json:"metadata,omitempty" db:"-"`
 }
 
 type PostEphemeral struct {
@@ -201,6 +203,8 @@ func (o *Post) ShallowCopy(dst *Post) error {
 	dst.PendingPostId = o.PendingPostId
 	dst.HasReactions = o.HasReactions
 	dst.ReplyCount = o.ReplyCount
+	dst.Participants = o.Participants
+	dst.LastReplyAt = o.LastReplyAt
 	dst.Metadata = o.Metadata
 	return nil
 }
@@ -225,17 +229,21 @@ func (o *Post) ToUnsanitizedJson() string {
 }
 
 type GetPostsSinceOptions struct {
-	ChannelId        string
+	ChannelId                string
-	Time             int64
+	Time                     int64
-	SkipFetchThreads bool
+	SkipFetchThreads         bool
+	CollapsedThreads         bool
+	CollapsedThreadsExtended bool
 }
 
 type GetPostsOptions struct {
-	ChannelId        string
+	ChannelId                string
-	PostId           string
+	PostId                   string
-	Page             int
+	Page                     int
-	PerPage          int
+	PerPage                  int
-	SkipFetchThreads bool
+	SkipFetchThreads         bool
+	CollapsedThreads         bool
+	CollapsedThreadsExtended bool
 }
 
 func PostFromJson(data io.Reader) *Post {
@@ -357,6 +365,9 @@ func (o *Post) SanitizeProps() {
 			o.DelProp(member)
 		}
 	}
+	for _, p := range o.Participants {
+		p.Sanitize(map[string]bool{})
+	}
 }
 
 func (o *Post) PreSave() {

store/localcachelayer/main_test.go

@@ -110,8 +110,8 @@ func getMockStore() *mocks.Store {
 	mockPostStoreEtagResult := fmt.Sprintf("%v.%v", model.CurrentVersion, 1)
 	mockPostStore.On("ClearCaches")
 	mockPostStore.On("InvalidateLastPostTimeCache", "channelId")
-	mockPostStore.On("GetEtag", "channelId", true).Return(mockPostStoreEtagResult)
+	mockPostStore.On("GetEtag", "channelId", true, false).Return(mockPostStoreEtagResult)
-	mockPostStore.On("GetEtag", "channelId", false).Return(mockPostStoreEtagResult)
+	mockPostStore.On("GetEtag", "channelId", false, false).Return(mockPostStoreEtagResult)
 	mockPostStore.On("GetPostsSince", mockPostStoreOptions, true).Return(model.NewPostList(), nil)
 	mockPostStore.On("GetPostsSince", mockPostStoreOptions, false).Return(model.NewPostList(), nil)
 	mockStore.On("Post").Return(&mockPostStore)

store/localcachelayer/post_layer.go

@@ -59,7 +59,7 @@ func (s LocalCachePostStore) InvalidateLastPostTimeCache(channelId string) {
 	}
 }
 
-func (s LocalCachePostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (s LocalCachePostStore) GetEtag(channelId string, allowFromCache, collapsedThreads bool) string {
 	if allowFromCache {
 		var lastTime int64
 		if err := s.rootStore.doStandardReadCache(s.rootStore.lastPostTimeCache, channelId, &lastTime); err == nil {
@@ -67,7 +67,7 @@ func (s LocalCachePostStore) GetEtag(channelId string, allowFromCache bool) stri
 		}
 	}
 
-	result := s.PostStore.GetEtag(channelId, allowFromCache)
+	result := s.PostStore.GetEtag(channelId, allowFromCache, collapsedThreads)
 
 	splittedResult := strings.Split(result, ".")
 

store/localcachelayer/post_layer_test.go

@@ -36,11 +36,11 @@ func TestPostStoreLastPostTimeCache(t *testing.T) {
 
 		expectedResult := fmt.Sprintf("%v.%v", model.CurrentVersion, fakeLastTime)
 
-		etag := cachedStore.Post().GetEtag(channelId, true)
+		etag := cachedStore.Post().GetEtag(channelId, true, false)
 		assert.Equal(t, etag, expectedResult)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 1)
 
-		etag = cachedStore.Post().GetEtag(channelId, true)
+		etag = cachedStore.Post().GetEtag(channelId, true, false)
 		assert.Equal(t, etag, expectedResult)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 1)
 	})
@@ -51,9 +51,9 @@ func TestPostStoreLastPostTimeCache(t *testing.T) {
 		cachedStore, err := NewLocalCacheLayer(mockStore, nil, nil, mockCacheProvider)
 		require.NoError(t, err)
 
-		cachedStore.Post().GetEtag(channelId, true)
+		cachedStore.Post().GetEtag(channelId, true, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 1)
-		cachedStore.Post().GetEtag(channelId, false)
+		cachedStore.Post().GetEtag(channelId, false, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 2)
 	})
 
@@ -63,10 +63,10 @@ func TestPostStoreLastPostTimeCache(t *testing.T) {
 		cachedStore, err := NewLocalCacheLayer(mockStore, nil, nil, mockCacheProvider)
 		require.NoError(t, err)
 
-		cachedStore.Post().GetEtag(channelId, true)
+		cachedStore.Post().GetEtag(channelId, true, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 1)
 		cachedStore.Post().InvalidateLastPostTimeCache(channelId)
-		cachedStore.Post().GetEtag(channelId, true)
+		cachedStore.Post().GetEtag(channelId, true, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 2)
 	})
 
@@ -76,10 +76,10 @@ func TestPostStoreLastPostTimeCache(t *testing.T) {
 		cachedStore, err := NewLocalCacheLayer(mockStore, nil, nil, mockCacheProvider)
 		require.NoError(t, err)
 
-		cachedStore.Post().GetEtag(channelId, true)
+		cachedStore.Post().GetEtag(channelId, true, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 1)
 		cachedStore.Post().ClearCaches()
-		cachedStore.Post().GetEtag(channelId, true)
+		cachedStore.Post().GetEtag(channelId, true, false)
 		mockStore.Post().(*mocks.PostStore).AssertNumberOfCalls(t, "GetEtag", 2)
 	})
 

store/opentracinglayer/opentracinglayer.go

@@ -4898,7 +4898,7 @@ func (s *OpenTracingLayerPostStore) Delete(postId string, time int64, deleteByID
 	return err
 }
 
-func (s *OpenTracingLayerPostStore) Get(id string, skipFetchThreads bool) (*model.PostList, error) {
+func (s *OpenTracingLayerPostStore) Get(id string, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.Get")
 	s.Root.Store.SetContext(newCtx)
@@ -4907,7 +4907,7 @@ func (s *OpenTracingLayerPostStore) Get(id string, skipFetchThreads bool) (*mode
 	}()
 
 	defer span.Finish()
-	result, err := s.PostStore.Get(id, skipFetchThreads)
+	result, err := s.PostStore.Get(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	if err != nil {
 		span.LogFields(spanlog.Error(err))
 		ext.Error.Set(span, true)
@@ -4934,7 +4934,7 @@ func (s *OpenTracingLayerPostStore) GetDirectPostParentsForExportAfter(limit int
 	return result, err
 }
 
-func (s *OpenTracingLayerPostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (s *OpenTracingLayerPostStore) GetEtag(channelId string, allowFromCache bool, collapsedThreads bool) string {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.GetEtag")
 	s.Root.Store.SetContext(newCtx)
@@ -4943,7 +4943,7 @@ func (s *OpenTracingLayerPostStore) GetEtag(channelId string, allowFromCache boo
 	}()
 
 	defer span.Finish()
-	result := s.PostStore.GetEtag(channelId, allowFromCache)
+	result := s.PostStore.GetEtag(channelId, allowFromCache, collapsedThreads)
 	return result
 }
 

store/retrylayer/retrylayer.go

@@ -5302,11 +5302,11 @@ func (s *RetryLayerPostStore) Delete(postId string, time int64, deleteByID strin
 
 }
 
-func (s *RetryLayerPostStore) Get(id string, skipFetchThreads bool) (*model.PostList, error) {
+func (s *RetryLayerPostStore) Get(id string, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, error) {
 
 	tries := 0
 	for {
-		result, err := s.PostStore.Get(id, skipFetchThreads)
+		result, err := s.PostStore.Get(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 		if err == nil {
 			return result, nil
 		}
@@ -5342,9 +5342,9 @@ func (s *RetryLayerPostStore) GetDirectPostParentsForExportAfter(limit int, afte
 
 }
 
-func (s *RetryLayerPostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (s *RetryLayerPostStore) GetEtag(channelId string, allowFromCache bool, collapsedThreads bool) string {
 
-	return s.PostStore.GetEtag(channelId, allowFromCache)
+	return s.PostStore.GetEtag(channelId, allowFromCache, collapsedThreads)
 
 }
 

store/searchlayer/post_layer.go

@@ -108,7 +108,7 @@ func (s SearchPostStore) Delete(postId string, date int64, deletedByID string) e
 	err := s.PostStore.Delete(postId, date, deletedByID)
 
 	if err == nil {
-		postList, err2 := s.PostStore.Get(postId, true)
+		postList, err2 := s.PostStore.Get(postId, true, false, false)
 		if postList != nil && len(postList.Order) > 0 {
 			if err2 != nil {
 				s.deletePostIndex(postList.Posts[postList.Order[0]])

store/sqlstore/post_store.go

@@ -30,6 +30,12 @@ type SqlPostStore struct {
 	maxPostSizeCached int
 }
 
+type postWithExtra struct {
+	ThreadReplyCount   int64
+	ThreadParticipants model.StringArray
+	model.Post
+}
+
 func (s *SqlPostStore) ClearCaches() {
 }
 
@@ -418,8 +424,40 @@ func (s *SqlPostStore) GetFlaggedPostsForChannel(userId, channelId string, offse
 
 	return pl, nil
 }
+func (s *SqlPostStore) getPostWithCollapsedThreads(id string, extended bool) (*model.PostList, error) {
+	if len(id) == 0 {
+		return nil, store.NewErrInvalidInput("Post", "id", id)
+	}
 
-func (s *SqlPostStore) Get(id string, skipFetchThreads bool) (*model.PostList, error) {
+	var columns []string
+	for _, c := range postSliceColumns() {
+		columns = append(columns, "Posts."+c)
+	}
+	columns = append(columns, "COALESCE(Threads.ReplyCount, 0) as ThreadReplyCount", "COALESCE(Threads.LastReplyAt, 0) as LastReplyAt", "COALESCE(Threads.Participants, '[]') as ThreadParticipants")
+	var post postWithExtra
+
+	postFetchQuery, args, _ := s.getQueryBuilder().
+		Select(columns...).
+		From("Posts").
+		LeftJoin("Threads ON Threads.PostId = Id").
+		Where(sq.Eq{"DeleteAt": 0}).
+		Where(sq.Eq{"Id": id}).ToSql()
+
+	err := s.GetReplica().SelectOne(&post, postFetchQuery, args...)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, store.NewErrNotFound("Post", id)
+		}
+
+		return nil, errors.Wrapf(err, "failed to get Post with id=%s", id)
+	}
+	return s.prepareThreadedResponse([]*postWithExtra{&post}, extended, false)
+}
+
+func (s *SqlPostStore) Get(id string, skipFetchThreads, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, error) {
+	if collapsedThreads {
+		return s.getPostWithCollapsedThreads(id, collapsedThreadsExtended)
+	}
 	pl := model.NewPostList()
 
 	if len(id) == 0 {
@@ -484,9 +522,14 @@ type etagPosts struct {
 func (s *SqlPostStore) InvalidateLastPostTimeCache(channelId string) {
 }
 
-func (s *SqlPostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (s *SqlPostStore) GetEtag(channelId string, allowFromCache, collapsedThreads bool) string {
+	q := s.getQueryBuilder().Select("Id", "UpdateAt").From("Posts").Where(sq.Eq{"ChannelId": channelId}).OrderBy("UpdateAt DESC").Limit(1)
+	if collapsedThreads {
+		q.Where(sq.Eq{"RootId": ""})
+	}
+	sql, args, _ := q.ToSql()
 	var et etagPosts
-	err := s.GetReplica().SelectOne(&et, "SELECT Id, UpdateAt FROM Posts WHERE ChannelId = :ChannelId ORDER BY UpdateAt DESC LIMIT 1", map[string]interface{}{"ChannelId": channelId})
+	err := s.GetReplica().SelectOne(&et, sql, args...)
 	var result string
 	if err != nil {
 		result = fmt.Sprintf("%v.%v", model.CurrentVersion, model.GetMillis())
@@ -616,10 +659,102 @@ func (s *SqlPostStore) PermanentDeleteByChannel(channelId string) error {
 	return nil
 }
 
+func (s *SqlPostStore) prepareThreadedResponse(posts []*postWithExtra, extended, reversed bool) (*model.PostList, error) {
+	list := model.NewPostList()
+	var userIds []string
+	userIdMap := map[string]bool{}
+	for _, thread := range posts {
+		for _, participantId := range thread.ThreadParticipants {
+			if _, ok := userIdMap[participantId]; !ok {
+				userIdMap[participantId] = true
+				userIds = append(userIds, participantId)
+			}
+		}
+	}
+	var users []*model.User
+	if extended {
+		var err error
+		users, err = s.User().GetProfileByIds(userIds, &store.UserGetByIdsOpts{}, true)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		for _, userId := range userIds {
+			users = append(users, &model.User{Id: userId})
+		}
+	}
+	processPost := func(p *postWithExtra) error {
+		p.Post.ReplyCount = p.ThreadReplyCount
+		for _, th := range p.ThreadParticipants {
+			var participant *model.User
+			for _, u := range users {
+				if u.Id == th {
+					participant = u
+					break
+				}
+			}
+			if participant == nil {
+				return errors.New("cannot find thread participant with id=" + th)
+			}
+			p.Post.Participants = append(p.Post.Participants, participant)
+		}
+		return nil
+	}
+
+	l := len(posts)
+	for i := range posts {
+		idx := i
+		// We need to flip the order if we selected backwards
+
+		if reversed {
+			idx = l - i - 1
+		}
+		if err := processPost(posts[idx]); err != nil {
+			return nil, err
+		}
+		list.AddPost(&posts[idx].Post)
+		list.AddOrder(posts[idx].Id)
+	}
+
+	return list, nil
+}
+
+func (s *SqlPostStore) getPostsCollapsedThreads(options model.GetPostsOptions) (*model.PostList, error) {
+	var columns []string
+	for _, c := range postSliceColumns() {
+		columns = append(columns, "Posts."+c)
+	}
+	columns = append(columns, "COALESCE(Threads.ReplyCount, 0) as ThreadReplyCount", "COALESCE(Threads.LastReplyAt, 0) as LastReplyAt", "COALESCE(Threads.Participants, '[]') as ThreadParticipants")
+	var posts []*postWithExtra
+	offset := options.PerPage * options.Page
+
+	postFetchQuery, args, _ := s.getQueryBuilder().
+		Select(columns...).
+		From("Posts").
+		LeftJoin("Threads ON Threads.PostId = Id").
+		Where(sq.Eq{"DeleteAt": 0}).
+		Where(sq.Eq{"Posts.ChannelId": options.ChannelId}).
+		Where(sq.Eq{"RootId": ""}).
+		Limit(uint64(options.PerPage)).
+		Offset(uint64(offset)).
+		OrderBy("CreateAt DESC").ToSql()
+
+	_, err := s.GetReplica().Select(&posts, postFetchQuery, args...)
+
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to find Posts with channelId=%s", options.ChannelId)
+	}
+
+	return s.prepareThreadedResponse(posts, options.CollapsedThreadsExtended, false)
+}
+
 func (s *SqlPostStore) GetPosts(options model.GetPostsOptions, _ bool) (*model.PostList, error) {
 	if options.PerPage > 1000 {
 		return nil, store.NewErrInvalidInput("Post", "<options.PerPage>", options.PerPage)
 	}
+	if options.CollapsedThreads {
+		return s.getPostsCollapsedThreads(options)
+	}
 	offset := options.PerPage * options.Page
 
 	rpc := make(chan store.StoreResult, 1)
@@ -664,7 +799,36 @@ func (s *SqlPostStore) GetPosts(options model.GetPostsOptions, _ bool) (*model.P
 	return list, nil
 }
 
+func (s *SqlPostStore) getPostsSinceCollapsedThreads(options model.GetPostsSinceOptions) (*model.PostList, error) {
+	var columns []string
+	for _, c := range postSliceColumns() {
+		columns = append(columns, "Posts."+c)
+	}
+	columns = append(columns, "COALESCE(Threads.ReplyCount, 0) as ThreadReplyCount", "COALESCE(Threads.LastReplyAt, 0) as LastReplyAt", "COALESCE(Threads.Participants, '[]') as ThreadParticipants")
+	var posts []*postWithExtra
+
+	postFetchQuery, args, _ := s.getQueryBuilder().
+		Select(columns...).
+		From("Posts").
+		LeftJoin("Threads ON Threads.PostId = Id").
+		Where(sq.Eq{"DeleteAt": 0}).
+		Where(sq.Eq{"Posts.ChannelId": options.ChannelId}).
+		Where(sq.Gt{"UpdateAt": options.Time}).
+		Where(sq.Eq{"RootId": ""}).
+		OrderBy("CreateAt DESC").ToSql()
+
+	_, err := s.GetReplica().Select(&posts, postFetchQuery, args...)
+
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to find Posts with channelId=%s", options.ChannelId)
+	}
+	return s.prepareThreadedResponse(posts, options.CollapsedThreadsExtended, false)
+}
+
 func (s *SqlPostStore) GetPostsSince(options model.GetPostsSinceOptions, allowFromCache bool) (*model.PostList, error) {
+	if options.CollapsedThreads {
+		return s.getPostsSinceCollapsedThreads(options)
+	}
 	var posts []*model.Post
 
 	replyCountQuery1 := ""
@@ -753,7 +917,8 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 	}
 
 	offset := options.Page * options.PerPage
-	var posts, parents []*model.Post
+	var posts []*postWithExtra
+	var parents []*model.Post
 
 	var direction string
 	var sort string
@@ -771,20 +936,30 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 	if s.DriverName() == model.DATABASE_DRIVER_MYSQL {
 		table += " USE INDEX(idx_posts_channel_id_delete_at_create_at)"
 	}
-
+	columns := []string{"p.*"}
+	if options.CollapsedThreads {
+		columns = append(columns, "COALESCE(Threads.ReplyCount, 0) as ThreadReplyCount", "COALESCE(Threads.LastReplyAt, 0) as LastReplyAt", "COALESCE(Threads.Participants, '[]') as ThreadParticipants")
+	}
+	query := s.getQueryBuilder().Select(columns...)
 	replyCountSubQuery := s.getQueryBuilder().Select("COUNT(Posts.Id)").From("Posts").Where(sq.Expr("Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0"))
-	query := s.getQueryBuilder().Select("p.*")
+
-	query = query.Column(sq.Alias(replyCountSubQuery, "ReplyCount"))
+	conditions := sq.And{
+		sq.Expr(`CreateAt `+direction+` (SELECT CreateAt FROM Posts WHERE Id = ?)`, options.PostId),
+		sq.Eq{"p.ChannelId": options.ChannelId},
+		sq.Eq{"DeleteAt": int(0)},
+	}
+	if options.CollapsedThreads {
+		conditions = append(conditions, sq.Eq{"RootId": ""})
+		query = query.LeftJoin("Threads ON Threads.PostId = p.Id")
+	} else {
+		query = query.Column(sq.Alias(replyCountSubQuery, "ReplyCount"))
+	}
 	query = query.From(table).
-		Where(sq.And{
+		Where(conditions).
-			sq.Expr(`CreateAt `+direction+` (SELECT CreateAt FROM Posts WHERE Id = ?)`, options.PostId),
-			sq.Eq{"ChannelId": options.ChannelId},
-			sq.Eq{"DeleteAt": int(0)},
-		}).
 		// Adding ChannelId and DeleteAt order columns
 		// to let mysql choose the "idx_posts_channel_id_delete_at_create_at" index always.
 		// See MM-24170.
-		OrderBy("ChannelId", "DeleteAt", "CreateAt "+sort).
+		OrderBy("p.ChannelId", "DeleteAt", "CreateAt "+sort).
 		Limit(uint64(options.PerPage)).
 		Offset(uint64(offset))
 
@@ -797,7 +972,7 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 		return nil, errors.Wrapf(err, "failed to find Posts with channelId=%s", options.ChannelId)
 	}
 
-	if len(posts) > 0 {
+	if !options.CollapsedThreads && len(posts) > 0 {
 		rootIds := []string{}
 		for _, post := range posts {
 			rootIds = append(rootIds, post.Id)
@@ -822,31 +997,20 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 			}).
 			OrderBy("CreateAt DESC")
 
-		rootQueryString, rootArgs, err := rootQuery.ToSql()
+		rootQueryString, rootArgs, nErr := rootQuery.ToSql()
 
-		if err != nil {
+		if nErr != nil {
-			return nil, errors.Wrap(err, "post_tosql")
+			return nil, errors.Wrap(nErr, "post_tosql")
 		}
-		_, err = s.GetMaster().Select(&parents, rootQueryString, rootArgs...)
+		_, nErr = s.GetMaster().Select(&parents, rootQueryString, rootArgs...)
-		if err != nil {
+		if nErr != nil {
-			return nil, errors.Wrapf(err, "failed to find Posts with channelId=%s", options.ChannelId)
+			return nil, errors.Wrapf(nErr, "failed to find Posts with channelId=%s", options.ChannelId)
 		}
 	}
 
-	list := model.NewPostList()
+	list, err := s.prepareThreadedResponse(posts, options.CollapsedThreadsExtended, !before)
-
+	if err != nil {
-	// We need to flip the order if we selected backwards
+		return nil, err
-	if before {
-		for _, p := range posts {
-			list.AddPost(p)
-			list.AddOrder(p.Id)
-		}
-	} else {
-		l := len(posts)
-		for i := range posts {
-			list.AddPost(posts[l-i-1])
-			list.AddOrder(posts[l-i-1].Id)
-		}
 	}
 
 	for _, p := range parents {

store/sqlstore/thread_store.go

@@ -234,8 +234,9 @@ func (s *SqlThreadStore) GetThreadsForUser(userId, teamId string, opts model.Get
 	}
 	var users []*model.User
 	if opts.Extended {
-		query, args, _ := s.getQueryBuilder().Select("*").From("Users").Where(sq.Eq{"Id": userIds}).ToSql()
+		var err error
-		if _, err := s.GetReplica().Select(&users, query, args...); err != nil {
+		users, err = s.User().GetProfileByIds(userIds, &store.UserGetByIdsOpts{}, true)
+		if err != nil {
 			return nil, errors.Wrapf(err, "failed to get threads for user id=%s", userId)
 		}
 	} else {
@@ -414,6 +415,18 @@ func (s *SqlThreadStore) CreateMembershipIfNeeded(userId, postId string, followi
 		LastUpdated:    now,
 		UnreadMentions: int64(mentions),
 	})
+	if err != nil {
+		return err
+	}
+
+	thread, err := s.Get(postId)
+	if err != nil {
+		return err
+	}
+	if !thread.Participants.Contains(userId) {
+		thread.Participants = append(thread.Participants, userId)
+		_, err = s.Update(thread)
+	}
 	return err
 }
 

store/sqlstore/upgrade.go

@@ -964,6 +964,7 @@ func upgradeDatabaseToVersion532(sqlStore *SqlStore) {
 	// if shouldPerformUpgrade(sqlStore, Version5310, Version5320) {
 	// allow 10 files per post
 	sqlStore.AlterColumnTypeIfExists("Posts", "FileIds", "text", "varchar(300)")
+	sqlStore.CreateColumnIfNotExists("ThreadMemberships", "UnreadMentions", "bigint", "bigint", "0")
 	sqlStore.CreateColumnIfNotExistsNoDefault("Channels", "Shared", "tinyint(1)", "boolean")
 	sqlStore.CreateColumnIfNotExists("ThreadMemberships", "UnreadMentions", "bigint", "bigint", "0")
 	// saveSchemaVersion(sqlStore, Version5320)

store/store.go

@@ -272,7 +272,7 @@ type PostStore interface {
 	SaveMultiple(posts []*model.Post) ([]*model.Post, int, error)
 	Save(post *model.Post) (*model.Post, error)
 	Update(newPost *model.Post, oldPost *model.Post) (*model.Post, error)
-	Get(id string, skipFetchThreads bool) (*model.PostList, error)
+	Get(id string, skipFetchThreads, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, error)
 	GetSingle(id string) (*model.Post, error)
 	Delete(postId string, time int64, deleteByID string) error
 	PermanentDeleteByUser(userId string) error
@@ -288,7 +288,7 @@ type PostStore interface {
 	GetPostAfterTime(channelId string, time int64) (*model.Post, error)
 	GetPostIdAfterTime(channelId string, time int64) (string, error)
 	GetPostIdBeforeTime(channelId string, time int64) (string, error)
-	GetEtag(channelId string, allowFromCache bool) string
+	GetEtag(channelId string, allowFromCache bool, collapsedThreads bool) string
 	Search(teamId string, userId string, params *model.SearchParams) (*model.PostList, error)
 	AnalyticsUserCountsWithPostsByDay(teamId string) (model.AnalyticsRows, error)
 	AnalyticsPostCountsByDay(options *model.AnalyticsPostCountsOptions) (model.AnalyticsRows, error)

store/storetest/mocks/PostStore.go

@@ -100,13 +100,13 @@ func (_m *PostStore) Delete(postId string, time int64, deleteByID string) error
 	return r0
 }
 
-// Get provides a mock function with given fields: id, skipFetchThreads
+// Get provides a mock function with given fields: id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended
-func (_m *PostStore) Get(id string, skipFetchThreads bool) (*model.PostList, error) {
+func (_m *PostStore) Get(id string, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, error) {
-	ret := _m.Called(id, skipFetchThreads)
+	ret := _m.Called(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 
 	var r0 *model.PostList
-	if rf, ok := ret.Get(0).(func(string, bool) *model.PostList); ok {
+	if rf, ok := ret.Get(0).(func(string, bool, bool, bool) *model.PostList); ok {
-		r0 = rf(id, skipFetchThreads)
+		r0 = rf(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	} else {
 		if ret.Get(0) != nil {
 			r0 = ret.Get(0).(*model.PostList)
@@ -114,8 +114,8 @@ func (_m *PostStore) Get(id string, skipFetchThreads bool) (*model.PostList, err
 	}
 
 	var r1 error
-	if rf, ok := ret.Get(1).(func(string, bool) error); ok {
+	if rf, ok := ret.Get(1).(func(string, bool, bool, bool) error); ok {
-		r1 = rf(id, skipFetchThreads)
+		r1 = rf(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 	} else {
 		r1 = ret.Error(1)
 	}
@@ -146,13 +146,13 @@ func (_m *PostStore) GetDirectPostParentsForExportAfter(limit int, afterId strin
 	return r0, r1
 }
 
-// GetEtag provides a mock function with given fields: channelId, allowFromCache
+// GetEtag provides a mock function with given fields: channelId, allowFromCache, collapsedThreads
-func (_m *PostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (_m *PostStore) GetEtag(channelId string, allowFromCache bool, collapsedThreads bool) string {
-	ret := _m.Called(channelId, allowFromCache)
+	ret := _m.Called(channelId, allowFromCache, collapsedThreads)
 
 	var r0 string
-	if rf, ok := ret.Get(0).(func(string, bool) string); ok {
+	if rf, ok := ret.Get(0).(func(string, bool, bool) string); ok {
-		r0 = rf(channelId, allowFromCache)
+		r0 = rf(channelId, allowFromCache, collapsedThreads)
 	} else {
 		r0 = ret.Get(0).(string)
 	}

store/storetest/post_store.go

@@ -407,23 +407,23 @@ func testPostStoreGet(t *testing.T, ss store.Store) {
 	o1.UserId = model.NewId()
 	o1.Message = "zz" + model.NewId() + "b"
 
-	etag1 := ss.Post().GetEtag(o1.ChannelId, false)
+	etag1 := ss.Post().GetEtag(o1.ChannelId, false, false)
 	require.Equal(t, 0, strings.Index(etag1, model.CurrentVersion+"."), "Invalid Etag")
 
 	o1, err := ss.Post().Save(o1)
 	require.Nil(t, err)
 
-	etag2 := ss.Post().GetEtag(o1.ChannelId, false)
+	etag2 := ss.Post().GetEtag(o1.ChannelId, false, false)
 	require.Equal(t, 0, strings.Index(etag2, fmt.Sprintf("%v.%v", model.CurrentVersion, o1.UpdateAt)), "Invalid Etag")
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	require.Equal(t, r1.Posts[o1.Id].CreateAt, o1.CreateAt, "invalid returned post")
 
-	_, err = ss.Post().Get("123", false)
+	_, err = ss.Post().Get("123", false, false, false)
 	require.NotNil(t, err, "Missing id should have failed")
 
-	_, err = ss.Post().Get("", false)
+	_, err = ss.Post().Get("", false, false, false)
 	require.NotNil(t, err, "should fail for blank post ids")
 }
 
@@ -468,15 +468,15 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	o3, err = ss.Post().Save(o3)
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro1 := r1.Posts[o1.Id]
 
-	r2, err := ss.Post().Get(o1.Id, false)
+	r2, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro2 := r2.Posts[o2.Id]
 
-	r3, err := ss.Post().Get(o3.Id, false)
+	r3, err := ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err)
 	ro3 := r3.Posts[o3.Id]
 
@@ -487,7 +487,7 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	_, err = ss.Post().Update(o1a, ro1)
 	require.Nil(t, err)
 
-	r1, err = ss.Post().Get(o1.Id, false)
+	r1, err = ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 
 	ro1a := r1.Posts[o1.Id]
@@ -498,7 +498,7 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	_, err = ss.Post().Update(o2a, ro2)
 	require.Nil(t, err)
 
-	r2, err = ss.Post().Get(o1.Id, false)
+	r2, err = ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro2a := r2.Posts[o2.Id]
 
@@ -509,7 +509,7 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	_, err = ss.Post().Update(o3a, ro3)
 	require.Nil(t, err)
 
-	r3, err = ss.Post().Get(o3.Id, false)
+	r3, err = ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err)
 	ro3a := r3.Posts[o3.Id]
 
@@ -525,7 +525,7 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	})
 	require.Nil(t, err)
 
-	r4, err := ss.Post().Get(o4.Id, false)
+	r4, err := ss.Post().Get(o4.Id, false, false, false)
 	require.Nil(t, err)
 	ro4 := r4.Posts[o4.Id]
 
@@ -535,7 +535,7 @@ func testPostStoreUpdate(t *testing.T, ss store.Store) {
 	_, err = ss.Post().Update(o4a, ro4)
 	require.Nil(t, err)
 
-	r4, err = ss.Post().Get(o4.Id, false)
+	r4, err = ss.Post().Get(o4.Id, false, false, false)
 	require.Nil(t, err)
 
 	ro4a := r4.Posts[o4.Id]
@@ -550,13 +550,13 @@ func testPostStoreDelete(t *testing.T, ss store.Store) {
 	o1.Message = "zz" + model.NewId() + "b"
 	deleteByID := model.NewId()
 
-	etag1 := ss.Post().GetEtag(o1.ChannelId, false)
+	etag1 := ss.Post().GetEtag(o1.ChannelId, false, false)
 	require.Equal(t, 0, strings.Index(etag1, model.CurrentVersion+"."), "Invalid Etag")
 
 	o1, err := ss.Post().Save(o1)
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	require.Equal(t, r1.Posts[o1.Id].CreateAt, o1.CreateAt, "invalid returned post")
 
@@ -569,10 +569,10 @@ func testPostStoreDelete(t *testing.T, ss store.Store) {
 
 	assert.Equal(t, deleteByID, actual, "Expected (*Post).Props[model.POST_PROPS_DELETE_BY] to be %v but got %v.", deleteByID, actual)
 
-	r3, err := ss.Post().Get(o1.Id, false)
+	r3, err := ss.Post().Get(o1.Id, false, false, false)
 	require.NotNil(t, err, "Missing id should have failed - PostList %v", r3)
 
-	etag2 := ss.Post().GetEtag(o1.ChannelId, false)
+	etag2 := ss.Post().GetEtag(o1.ChannelId, false, false)
 	require.Equal(t, 0, strings.Index(etag2, model.CurrentVersion+"."), "Invalid Etag")
 }
 
@@ -596,10 +596,10 @@ func testPostStoreDelete1Level(t *testing.T, ss store.Store) {
 	err = ss.Post().Delete(o1.Id, model.GetMillis(), "")
 	require.Nil(t, err)
 
-	_, err = ss.Post().Get(o1.Id, false)
+	_, err = ss.Post().Get(o1.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o2.Id, false)
+	_, err = ss.Post().Get(o2.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 }
 
@@ -639,16 +639,16 @@ func testPostStoreDelete2Level(t *testing.T, ss store.Store) {
 	err = ss.Post().Delete(o1.Id, model.GetMillis(), "")
 	require.Nil(t, err)
 
-	_, err = ss.Post().Get(o1.Id, false)
+	_, err = ss.Post().Get(o1.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o2.Id, false)
+	_, err = ss.Post().Get(o2.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o3.Id, false)
+	_, err = ss.Post().Get(o3.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o4.Id, false)
+	_, err = ss.Post().Get(o4.Id, false, false, false)
 	require.Nil(t, err)
 }
 
@@ -679,16 +679,16 @@ func testPostStorePermDelete1Level(t *testing.T, ss store.Store) {
 	err2 := ss.Post().PermanentDeleteByUser(o2.UserId)
 	require.Nil(t, err2)
 
-	_, err = ss.Post().Get(o1.Id, false)
+	_, err = ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err, "Deleted id shouldn't have failed")
 
-	_, err = ss.Post().Get(o2.Id, false)
+	_, err = ss.Post().Get(o2.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
 	err = ss.Post().PermanentDeleteByChannel(o3.ChannelId)
 	require.Nil(t, err)
 
-	_, err = ss.Post().Get(o3.Id, false)
+	_, err = ss.Post().Get(o3.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 }
 
@@ -719,13 +719,13 @@ func testPostStorePermDelete1Level2(t *testing.T, ss store.Store) {
 	err2 := ss.Post().PermanentDeleteByUser(o1.UserId)
 	require.Nil(t, err2)
 
-	_, err = ss.Post().Get(o1.Id, false)
+	_, err = ss.Post().Get(o1.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o2.Id, false)
+	_, err = ss.Post().Get(o2.Id, false, false, false)
 	require.NotNil(t, err, "Deleted id should have failed")
 
-	_, err = ss.Post().Get(o3.Id, false)
+	_, err = ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err, "Deleted id should have failed")
 }
 
@@ -755,7 +755,7 @@ func testPostStoreGetWithChildren(t *testing.T, ss store.Store) {
 	o3, err = ss.Post().Save(o3)
 	require.Nil(t, err)
 
-	pl, err := ss.Post().Get(o1.Id, false)
+	pl, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 
 	require.Len(t, pl.Posts, 3, "invalid returned post")
@@ -763,7 +763,7 @@ func testPostStoreGetWithChildren(t *testing.T, ss store.Store) {
 	dErr := ss.Post().Delete(o3.Id, model.GetMillis(), "")
 	require.Nil(t, dErr)
 
-	pl, err = ss.Post().Get(o1.Id, false)
+	pl, err = ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 
 	require.Len(t, pl.Posts, 2, "invalid returned post")
@@ -771,7 +771,7 @@ func testPostStoreGetWithChildren(t *testing.T, ss store.Store) {
 	dErr = ss.Post().Delete(o2.Id, model.GetMillis(), "")
 	require.Nil(t, dErr)
 
-	pl, err = ss.Post().Get(o1.Id, false)
+	pl, err = ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 
 	require.Len(t, pl.Posts, 1, "invalid returned post")
@@ -1181,6 +1181,101 @@ func testPostStoreGetPostsBeforeAfter(t *testing.T, ss store.Store) {
 			}, postList.Posts)
 		})
 	})
+	t.Run("with threads (collapsedThreads)", func(t *testing.T) {
+		channelId := model.NewId()
+		userId := model.NewId()
+
+		// This creates a series of posts that looks like:
+		// post1
+		// post2
+		// post3 (in response to post1)
+		// post4 (in response to post2)
+		// post5
+		// post6 (in response to post2)
+
+		post1, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			Message:   "post1",
+		})
+		require.Nil(t, err)
+		post1.ReplyCount = 1
+		time.Sleep(time.Millisecond)
+
+		post2, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			Message:   "post2",
+		})
+		require.Nil(t, err)
+		post2.ReplyCount = 2
+		time.Sleep(time.Millisecond)
+
+		post3, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			ParentId:  post1.Id,
+			RootId:    post1.Id,
+			Message:   "post3",
+		})
+		require.Nil(t, err)
+		post3.ReplyCount = 1
+		time.Sleep(time.Millisecond)
+
+		post4, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			RootId:    post2.Id,
+			ParentId:  post2.Id,
+			Message:   "post4",
+		})
+		require.Nil(t, err)
+		post4.ReplyCount = 2
+		time.Sleep(time.Millisecond)
+
+		post5, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			Message:   "post5",
+		})
+		require.Nil(t, err)
+		time.Sleep(time.Millisecond)
+
+		post6, err := ss.Post().Save(&model.Post{
+			ChannelId: channelId,
+			UserId:    userId,
+			ParentId:  post2.Id,
+			RootId:    post2.Id,
+			Message:   "post6",
+		})
+		post6.ReplyCount = 2
+		require.Nil(t, err)
+
+		// Adding a post to a thread changes the UpdateAt timestamp of the parent post
+		post1.UpdateAt = post3.UpdateAt
+		post2.UpdateAt = post6.UpdateAt
+
+		t.Run("should return each root post before a post", func(t *testing.T) {
+			postList, err := ss.Post().GetPostsBefore(model.GetPostsOptions{ChannelId: channelId, PostId: post4.Id, PerPage: 2, CollapsedThreads: true})
+			assert.Nil(t, err)
+
+			assert.Equal(t, []string{post2.Id, post1.Id}, postList.Order)
+		})
+
+		t.Run("should return each root post before a post with limit", func(t *testing.T) {
+			postList, err := ss.Post().GetPostsBefore(model.GetPostsOptions{ChannelId: channelId, PostId: post4.Id, PerPage: 1, CollapsedThreads: true})
+			assert.Nil(t, err)
+
+			assert.Equal(t, []string{post2.Id}, postList.Order)
+		})
+
+		t.Run("should return each root after a post", func(t *testing.T) {
+			postList, err := ss.Post().GetPostsAfter(model.GetPostsOptions{ChannelId: channelId, PostId: post4.Id, PerPage: 2, CollapsedThreads: true})
+			require.Nil(t, err)
+
+			assert.Equal(t, []string{post5.Id}, postList.Order)
+		})
+	})
 }
 
 func testPostStoreGetPostsSince(t *testing.T, ss store.Store) {
@@ -2146,23 +2241,23 @@ func testPostStoreOverwriteMultiple(t *testing.T, ss store.Store) {
 	})
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro1 := r1.Posts[o1.Id]
 
-	r2, err := ss.Post().Get(o2.Id, false)
+	r2, err := ss.Post().Get(o2.Id, false, false, false)
 	require.Nil(t, err)
 	ro2 := r2.Posts[o2.Id]
 
-	r3, err := ss.Post().Get(o3.Id, false)
+	r3, err := ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err)
 	ro3 := r3.Posts[o3.Id]
 
-	r4, err := ss.Post().Get(o4.Id, false)
+	r4, err := ss.Post().Get(o4.Id, false, false, false)
 	require.Nil(t, err)
 	ro4 := r4.Posts[o4.Id]
 
-	r5, err := ss.Post().Get(o5.Id, false)
+	r5, err := ss.Post().Get(o5.Id, false, false, false)
 	require.Nil(t, err)
 	ro5 := r5.Posts[o5.Id]
 
@@ -2188,15 +2283,15 @@ func testPostStoreOverwriteMultiple(t *testing.T, ss store.Store) {
 		require.Nil(t, err)
 		require.Equal(t, -1, errIdx)
 
-		r1, nErr := ss.Post().Get(o1.Id, false)
+		r1, nErr := ss.Post().Get(o1.Id, false, false, false)
 		require.Nil(t, nErr)
 		ro1a := r1.Posts[o1.Id]
 
-		r2, nErr = ss.Post().Get(o1.Id, false)
+		r2, nErr = ss.Post().Get(o1.Id, false, false, false)
 		require.Nil(t, nErr)
 		ro2a := r2.Posts[o2.Id]
 
-		r3, nErr = ss.Post().Get(o3.Id, false)
+		r3, nErr = ss.Post().Get(o3.Id, false, false, false)
 		require.Nil(t, nErr)
 		ro3a := r3.Posts[o3.Id]
 
@@ -2218,11 +2313,11 @@ func testPostStoreOverwriteMultiple(t *testing.T, ss store.Store) {
 		require.Nil(t, err)
 		require.Equal(t, -1, errIdx)
 
-		r4, nErr := ss.Post().Get(o4.Id, false)
+		r4, nErr := ss.Post().Get(o4.Id, false, false, false)
 		require.Nil(t, nErr)
 		ro4a := r4.Posts[o4.Id]
 
-		r5, nErr = ss.Post().Get(o5.Id, false)
+		r5, nErr = ss.Post().Get(o5.Id, false, false, false)
 		require.Nil(t, nErr)
 		ro5a := r5.Posts[o5.Id]
 
@@ -2265,19 +2360,19 @@ func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 	})
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro1 := r1.Posts[o1.Id]
 
-	r2, err := ss.Post().Get(o2.Id, false)
+	r2, err := ss.Post().Get(o2.Id, false, false, false)
 	require.Nil(t, err)
 	ro2 := r2.Posts[o2.Id]
 
-	r3, err := ss.Post().Get(o3.Id, false)
+	r3, err := ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err)
 	ro3 := r3.Posts[o3.Id]
 
-	r4, err := ss.Post().Get(o4.Id, false)
+	r4, err := ss.Post().Get(o4.Id, false, false, false)
 	require.Nil(t, err)
 	ro4 := r4.Posts[o4.Id]
 
@@ -2302,15 +2397,15 @@ func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 		_, err = ss.Post().Overwrite(o3a)
 		require.Nil(t, err)
 
-		r1, err = ss.Post().Get(o1.Id, false)
+		r1, err = ss.Post().Get(o1.Id, false, false, false)
 		require.Nil(t, err)
 		ro1a := r1.Posts[o1.Id]
 
-		r2, err = ss.Post().Get(o1.Id, false)
+		r2, err = ss.Post().Get(o1.Id, false, false, false)
 		require.Nil(t, err)
 		ro2a := r2.Posts[o2.Id]
 
-		r3, err = ss.Post().Get(o3.Id, false)
+		r3, err = ss.Post().Get(o3.Id, false, false, false)
 		require.Nil(t, err)
 		ro3a := r3.Posts[o3.Id]
 
@@ -2326,7 +2421,7 @@ func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 		_, err = ss.Post().Overwrite(o4a)
 		require.Nil(t, err)
 
-		r4, err = ss.Post().Get(o4.Id, false)
+		r4, err = ss.Post().Get(o4.Id, false, false, false)
 		require.Nil(t, err)
 
 		ro4a := r4.Posts[o4.Id]
@@ -2357,15 +2452,15 @@ func testPostStoreGetPostsByIds(t *testing.T, ss store.Store) {
 	o3, err = ss.Post().Save(o3)
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
+	r1, err := ss.Post().Get(o1.Id, false, false, false)
 	require.Nil(t, err)
 	ro1 := r1.Posts[o1.Id]
 
-	r2, err := ss.Post().Get(o2.Id, false)
+	r2, err := ss.Post().Get(o2.Id, false, false, false)
 	require.Nil(t, err)
 	ro2 := r2.Posts[o2.Id]
 
-	r3, err := ss.Post().Get(o3.Id, false)
+	r3, err := ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err)
 	ro3 := r3.Posts[o3.Id]
 
@@ -2472,13 +2567,13 @@ func testPostStorePermanentDeleteBatch(t *testing.T, ss store.Store) {
 	_, err = ss.Post().PermanentDeleteBatch(2000, 1000)
 	require.Nil(t, err)
 
-	_, err = ss.Post().Get(o1.Id, false)
+	_, err = ss.Post().Get(o1.Id, false, false, false)
 	require.NotNil(t, err, "Should have not found post 1 after purge")
 
-	_, err = ss.Post().Get(o2.Id, false)
+	_, err = ss.Post().Get(o2.Id, false, false, false)
 	require.NotNil(t, err, "Should have not found post 2 after purge")
 
-	_, err = ss.Post().Get(o3.Id, false)
+	_, err = ss.Post().Get(o3.Id, false, false, false)
 	require.Nil(t, err, "Should have not found post 3 after purge")
 }
 

store/storetest/reaction_store.go

@@ -50,7 +50,7 @@ func testReactionSave(t *testing.T, ss store.Store) {
 	assert.Equal(t, saved.EmojiName, reaction1.EmojiName, "should've saved reaction emoji_name and returned it")
 
 	var secondUpdateAt int64
-	postList, err := ss.Post().Get(reaction1.PostId, false)
+	postList, err := ss.Post().Get(reaction1.PostId, false, false, false)
 	require.Nil(t, err)
 
 	assert.True(t, postList.Posts[post.Id].HasReactions, "should've set HasReactions = true on post")
@@ -74,7 +74,7 @@ func testReactionSave(t *testing.T, ss store.Store) {
 	_, nErr = ss.Reaction().Save(reaction2)
 	require.Nil(t, nErr)
 
-	postList, err = ss.Post().Get(reaction2.PostId, false)
+	postList, err = ss.Post().Get(reaction2.PostId, false, false, false)
 	require.Nil(t, err)
 
 	assert.NotEqual(t, postList.Posts[post.Id].UpdateAt, secondUpdateAt, "should've marked post as updated even if HasReactions doesn't change")
@@ -123,7 +123,7 @@ func testReactionDelete(t *testing.T, ss store.Store) {
 	_, nErr := ss.Reaction().Save(reaction)
 	require.Nil(t, nErr)
 
-	result, err := ss.Post().Get(reaction.PostId, false)
+	result, err := ss.Post().Get(reaction.PostId, false, false, false)
 	require.Nil(t, err)
 
 	firstUpdateAt := result.Posts[post.Id].UpdateAt
@@ -136,7 +136,7 @@ func testReactionDelete(t *testing.T, ss store.Store) {
 
 	assert.Empty(t, reactions, "should've deleted reaction")
 
-	postList, err := ss.Post().Get(post.Id, false)
+	postList, err := ss.Post().Get(post.Id, false, false, false)
 	require.Nil(t, err)
 
 	assert.False(t, postList.Posts[post.Id].HasReactions, "should've set HasReactions = false on post")
@@ -297,15 +297,15 @@ func testReactionDeleteAllWithEmojiName(t *testing.T, ss store.Store) {
 	assert.Empty(t, returned, "should've only removed reactions with emoji name")
 
 	// check that the posts are updated
-	postList, err := ss.Post().Get(post.Id, false)
+	postList, err := ss.Post().Get(post.Id, false, false, false)
 	require.Nil(t, err)
 	assert.True(t, postList.Posts[post.Id].HasReactions, "post should still have reactions")
 
-	postList, err = ss.Post().Get(post2.Id, false)
+	postList, err = ss.Post().Get(post2.Id, false, false, false)
 	require.Nil(t, err)
 	assert.True(t, postList.Posts[post2.Id].HasReactions, "post should still have reactions")
 
-	postList, err = ss.Post().Get(post3.Id, false)
+	postList, err = ss.Post().Get(post3.Id, false, false, false)
 	require.Nil(t, err)
 	assert.False(t, postList.Posts[post3.Id].HasReactions, "post shouldn't have reactions any more")
 

store/storetest/thread_store.go

@@ -69,7 +69,7 @@ func testThreadStorePopulation(t *testing.T, ss store.Store) {
 
 		newPosts, errIdx, err3 := ss.Post().SaveMultiple([]*model.Post{&o2, &o3, &o4})
 
-		olist, _ := ss.Post().Get(otmp.Id, true)
+		olist, _ := ss.Post().Get(otmp.Id, true, false, false)
 		o1 := olist.Posts[olist.Order[0]]
 
 		newPosts = append([]*model.Post{o1}, newPosts...)

store/timerlayer/timerlayer.go

@@ -4444,10 +4444,10 @@ func (s *TimerLayerPostStore) Delete(postId string, time int64, deleteByID strin
 	return err
 }
 
-func (s *TimerLayerPostStore) Get(id string, skipFetchThreads bool) (*model.PostList, error) {
+func (s *TimerLayerPostStore) Get(id string, skipFetchThreads bool, collapsedThreads bool, collapsedThreadsExtended bool) (*model.PostList, error) {
 	start := timemodule.Now()
 
-	result, err := s.PostStore.Get(id, skipFetchThreads)
+	result, err := s.PostStore.Get(id, skipFetchThreads, collapsedThreads, collapsedThreadsExtended)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {
@@ -4476,10 +4476,10 @@ func (s *TimerLayerPostStore) GetDirectPostParentsForExportAfter(limit int, afte
 	return result, err
 }
 
-func (s *TimerLayerPostStore) GetEtag(channelId string, allowFromCache bool) string {
+func (s *TimerLayerPostStore) GetEtag(channelId string, allowFromCache bool, collapsedThreads bool) string {
 	start := timemodule.Now()
 
-	result := s.PostStore.GetEtag(channelId, allowFromCache)
+	result := s.PostStore.GetEtag(channelId, allowFromCache, collapsedThreads)
 
 	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
 	if s.Root.Metrics != nil {