[MM-42191]: Include deleted posts (#19985)

* MM-42191: Include deleted posts: Add includeDeleted query parameter for getPostsForChannel

* MM-42191: Fix error typo for includeDeleted query parameter

* MM-42191: Include deleted posts: Set permission error when deleted posts are requested by non system admins

* MM-42191: Include deleted posts: Refactor replyCountSubQuery and conditions when includeDeleted is not presented, refactor getRootPosts

* MM-42191: Include deleted posts: Refactor getRootPosts function along with skipFetchThreads and includeDeleted

* MM-42191: Include deleted posts: Rename includeDeleted to include_deleted param

* MM-42191: Include deleted posts: Fix failed posts unit tests

* MM-42191: Include deleted posts: Add missing include deleted option in multiple queries

* MM-42191: Include deleted posts: Add tests for include deleted option in TestGetPostsForChannel, TestGetPostsBefore, TestGetPostsAfter

* MM-42191: include deleted posts: Add tests cases for post store test

* MM-42191: Include deleted posts: Add extra unit test to ensure not returning deleted posts when IncludeDelete is false

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/commands_test.go

@@ -33,7 +33,7 @@ func TestEchoCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1, _, err := client.GetPostsForChannel(channel1.Id, 0, 2, "", false)
+	p1, _, err := client.GetPostsForChannel(channel1.Id, 0, 2, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, p1.Order, 2, "Echo command failed to send")
 }
@@ -352,7 +352,7 @@ func TestMeCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1, _, err := client.GetPostsForChannel(channel.Id, 0, 2, "", false)
+	p1, _, err := client.GetPostsForChannel(channel.Id, 0, 2, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, p1.Order, 2, "Command failed to send")
 
@@ -454,7 +454,7 @@ func TestShrugCommand(t *testing.T) {
 
 	time.Sleep(100 * time.Millisecond)
 
-	p1, _, err := client.GetPostsForChannel(channel.Id, 0, 2, "", false)
+	p1, _, err := client.GetPostsForChannel(channel.Id, 0, 2, "", false, false)
 	require.NoError(t, err)
 	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

@@ -183,10 +183,16 @@ 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"
+	includeDeleted := r.URL.Query().Get("include_deleted") == "true"
 	channelId := c.Params.ChannelId
 	page := c.Params.Page
 	perPage := c.Params.PerPage
 
+	if !c.IsSystemAdmin() && includeDeleted {
+		c.SetPermissionError(model.PermissionReadDeletedPosts)
+		return
+	}
+
 	if !c.App.SessionHasPermissionToChannel(c.AppContext, *c.AppContext.Session(), channelId, model.PermissionReadChannel) {
 		c.SetPermissionError(model.PermissionReadChannel)
 		return
@@ -217,7 +223,7 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		list, err = c.App.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: afterPost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, UserId: c.AppContext.Session().UserId})
+		list, err = c.App.GetPostsAfterPost(model.GetPostsOptions{ChannelId: channelId, PostId: afterPost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, UserId: c.AppContext.Session().UserId, IncludeDeleted: includeDeleted})
 	} else if beforePost != "" {
 		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
@@ -225,7 +231,7 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		list, err = c.App.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: beforePost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended, UserId: c.AppContext.Session().UserId})
+		list, err = c.App.GetPostsBeforePost(model.GetPostsOptions{ChannelId: channelId, PostId: beforePost, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended, UserId: c.AppContext.Session().UserId, IncludeDeleted: includeDeleted})
 	} else {
 		etag = c.App.GetPostsEtag(channelId, collapsedThreads)
 
@@ -233,7 +239,7 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		list, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended, UserId: c.AppContext.Session().UserId})
+		list, err = c.App.GetPostsPage(model.GetPostsOptions{ChannelId: channelId, Page: page, PerPage: perPage, SkipFetchThreads: skipFetchThreads, CollapsedThreads: collapsedThreads, CollapsedThreadsExtended: collapsedThreadsExtended, UserId: c.AppContext.Session().UserId, IncludeDeleted: includeDeleted})
 	}
 
 	if err != nil {

api4/post_test.go

@@ -1068,17 +1068,17 @@ func TestGetPostsForChannel(t *testing.T) {
 	post4 := th.CreatePost()
 
 	th.TestForAllClients(t, func(t *testing.T, c *model.Client4) {
-		posts, resp, err := c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false)
+		posts, resp, err := c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false, false)
 		require.NoError(t, err)
 		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, false)
+		posts, resp, _ = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, resp.Etag, false, false)
 		CheckEtag(t, posts, resp)
 
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 3, "wrong number returned")
 
@@ -1087,11 +1087,11 @@ func TestGetPostsForChannel(t *testing.T) {
 		_, ok = posts.Posts[post1.Id]
 		require.True(t, ok, "missing root post")
 
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 1, 1, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 1, 1, "", false, false)
 		require.NoError(t, err)
 		require.Equal(t, post3.Id, posts.Order[0], "wrong order")
 
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 10000, 10000, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 10000, 10000, "", false, false)
 		require.NoError(t, err)
 		require.Empty(t, posts.Order, "should be no posts")
 	})
@@ -1121,21 +1121,21 @@ func TestGetPostsForChannel(t *testing.T) {
 			require.True(t, f, "missing post")
 		}
 
-		_, resp, err := c.GetPostsForChannel("", 0, 60, "", false)
+		_, resp, err := c.GetPostsForChannel("", 0, 60, "", false, false)
 		require.Error(t, err)
 		CheckBadRequestStatus(t, resp)
 
-		_, resp, err = c.GetPostsForChannel("junk", 0, 60, "", false)
+		_, resp, err = c.GetPostsForChannel("junk", 0, 60, "", false, false)
 		require.Error(t, err)
 		CheckBadRequestStatus(t, resp)
 	})
 
-	_, resp, err := client.GetPostsForChannel(model.NewId(), 0, 60, "", false)
+	_, resp, err := client.GetPostsForChannel(model.NewId(), 0, 60, "", false, false)
 	require.Error(t, err)
 	CheckForbiddenStatus(t, resp)
 
 	client.Logout()
-	_, resp, err = client.GetPostsForChannel(model.NewId(), 0, 60, "", false)
+	_, resp, err = client.GetPostsForChannel(model.NewId(), 0, 60, "", false, false)
 	require.Error(t, err)
 	CheckUnauthorizedStatus(t, resp)
 
@@ -1151,12 +1151,12 @@ 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, _, err = c.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
+		posts, _, err = c.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false, false)
 		require.NoError(t, err)
 		systemPostId1 := posts.Order[1]
 
 		// similar to '/posts'
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 60, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 12, "expected 12 posts")
 		require.Equal(t, post10.Id, posts.Order[0], "posts not in order")
@@ -1165,7 +1165,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 		// similar to '/posts?per_page=3'
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 3, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post10.Id, posts.Order[0], "posts not in order")
@@ -1174,7 +1174,7 @@ 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, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 1, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 1, 3, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post7.Id, posts.Order[0], "posts not in order")
@@ -1183,7 +1183,7 @@ 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, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 2, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 2, 3, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post4.Id, posts.Order[0], "posts not in order")
@@ -1192,7 +1192,7 @@ 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, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 3, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 3, 3, "", false, false)
 		require.NoError(t, err)
 		require.Len(t, posts.Order, 3, "expected 3 posts")
 		require.Equal(t, post1.Id, posts.Order[0], "posts not in order")
@@ -1201,7 +1201,7 @@ func TestGetPostsForChannel(t *testing.T) {
 		require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 		// similar to '/posts?per_page=3&page=4'
-		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 4, 3, "", false)
+		posts, _, err = c.GetPostsForChannel(th.BasicChannel.Id, 4, 3, "", false, false)
 		require.NoError(t, err)
 		require.Empty(t, posts.Order, "should return 0 post")
 		require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1220,15 +1220,37 @@ func TestGetPostsForChannel(t *testing.T) {
 		})
 
 		// the endpoint should work fine when viewing archived channels is enabled
-		_, _, err = c.GetPostsForChannel(channel.Id, 0, 10, "", false)
+		_, _, err = c.GetPostsForChannel(channel.Id, 0, 10, "", false, false)
 		require.NoError(t, err)
 
 		// the endpoint should return forbidden if viewing archived channels is disabled
 		th.App.UpdateConfig(func(cfg *model.Config) { *cfg.TeamSettings.ExperimentalViewArchivedChannels = false })
-		_, resp, err = c.GetPostsForChannel(channel.Id, 0, 10, "", false)
+		_, resp, err = c.GetPostsForChannel(channel.Id, 0, 10, "", false, false)
 		require.Error(t, err)
 		CheckForbiddenStatus(t, resp)
 	}, "Should forbid to retrieve posts if the channel is archived and users are not allowed to view archived messages")
+
+	client.DeletePost(post10.Id)
+	client.DeletePost(post8.Id)
+
+	// include deleted posts for non-admin users.
+	_, resp, err = client.GetPostsForChannel(th.BasicChannel.Id, 0, 100, "", false, true)
+	require.Error(t, err)
+	CheckForbiddenStatus(t, resp)
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		// include deleted posts for admin users.
+		posts, resp, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 100, "", false, true)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 12, "expected 12 posts")
+
+		// not include deleted posts for admin users.
+		posts, resp, err = c.GetPostsForChannel(th.BasicChannel.Id, 0, 100, "", false, false)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 10, "expected 10 posts")
+	})
 }
 
 func TestGetFlaggedPostsForUser(t *testing.T) {
@@ -1440,7 +1462,7 @@ func TestGetPostsBefore(t *testing.T) {
 	post4 := th.CreatePost()
 	post5 := th.CreatePost()
 
-	posts, _, err := client.GetPostsBefore(th.BasicChannel.Id, post3.Id, 0, 100, "", false)
+	posts, _, err := client.GetPostsBefore(th.BasicChannel.Id, post3.Id, 0, 100, "", false, false)
 	require.NoError(t, err)
 
 	found := make([]bool, 2)
@@ -1462,18 +1484,18 @@ 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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post4.Id, 1, 1, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post4.Id, 1, 1, "", false, false)
 	require.NoError(t, err)
 	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")
 
-	_, resp, err := client.GetPostsBefore(th.BasicChannel.Id, "junk", 1, 1, "", false)
+	_, resp, err := client.GetPostsBefore(th.BasicChannel.Id, "junk", 1, 1, "", false, false)
 	require.Error(t, err)
 	CheckBadRequestStatus(t, resp)
 
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 0, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 0, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post4.Id, posts.Order[0], "should match returned post")
@@ -1482,12 +1504,12 @@ 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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false, false)
 	require.NoError(t, err)
 	systemPostId2 := posts.Order[0]
 	systemPostId1 := posts.Order[1]
 
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 1, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post5.Id, 1, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post1.Id, posts.Order[0], "should match returned post")
@@ -1502,10 +1524,10 @@ func TestGetPostsBefore(t *testing.T) {
 	th.CreatePost() // post7
 	post8 := th.CreatePost()
 	post9 := th.CreatePost()
-	th.CreatePost() // post10
+	post10 := th.CreatePost() // post10
 
 	// similar to '/posts?before=post9'
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 60, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 60, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 10, "expected 10 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "posts not in order")
@@ -1514,7 +1536,7 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 	// similar to '/posts?before=post9&per_page=3'
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "posts not in order")
@@ -1523,7 +1545,7 @@ 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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 1, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 1, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post5.Id, posts.Order[0], "posts not in order")
@@ -1532,7 +1554,7 @@ 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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 2, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 2, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post2.Id, posts.Order[0], "posts not in order")
@@ -1541,7 +1563,7 @@ 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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 3, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 2, "expected 2 posts")
 	require.Equal(t, systemPostId2, posts.Order[0], "posts not in order")
@@ -1550,14 +1572,14 @@ func TestGetPostsBefore(t *testing.T) {
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
 
 	// similar to '/posts?before=systemPostId1'
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 0, 60, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 0, 60, "", false, false)
 	require.NoError(t, err)
 	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, _, err = client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 1, 60, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, systemPostId1, 1, 60, "", false, false)
 	require.NoError(t, err)
 	require.Empty(t, posts.Order, "should return 0 posts")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1565,11 +1587,33 @@ func TestGetPostsBefore(t *testing.T) {
 
 	// similar to '/posts?before=non-existent-post'
 	nonExistentPostId := model.NewId()
-	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false, false)
 	require.NoError(t, err)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, nonExistentPostId, posts.NextPostId, "should return nonExistentPostId as NextPostId")
 	require.Equal(t, "", posts.PrevPostId, "should return an empty PrevPostId")
+
+	client.DeletePost(post9.Id)
+	client.DeletePost(post8.Id)
+
+	// include deleted posts for non-admin users.
+	_, resp, err = client.GetPostsBefore(th.BasicChannel.Id, post9.Id, 0, 60, "", false, true)
+	require.Error(t, err)
+	CheckForbiddenStatus(t, resp)
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		// include deleted posts for admin users.
+		posts, resp, err = c.GetPostsBefore(th.BasicChannel.Id, post10.Id, 0, 60, "", false, true)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 11, "expected 11 posts")
+
+		// not include deleted posts for admin users.
+		posts, resp, err = c.GetPostsBefore(th.BasicChannel.Id, post10.Id, 0, 60, "", false, false)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 9, "expected 9 posts")
+	})
 }
 
 func TestGetPostsAfter(t *testing.T) {
@@ -1583,7 +1627,7 @@ func TestGetPostsAfter(t *testing.T) {
 	post4 := th.CreatePost()
 	post5 := th.CreatePost()
 
-	posts, _, err := client.GetPostsAfter(th.BasicChannel.Id, post3.Id, 0, 100, "", false)
+	posts, _, err := client.GetPostsAfter(th.BasicChannel.Id, post3.Id, 0, 100, "", false, false)
 	require.NoError(t, err)
 
 	found := make([]bool, 2)
@@ -1603,18 +1647,18 @@ 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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 1, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 1, "", false, false)
 	require.NoError(t, err)
 	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")
 
-	_, resp, err := client.GetPostsAfter(th.BasicChannel.Id, "junk", 1, 1, "", false)
+	_, resp, err := client.GetPostsAfter(th.BasicChannel.Id, "junk", 1, 1, "", false, false)
 	require.Error(t, err)
 	CheckBadRequestStatus(t, resp)
 
-	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 3, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Posts, 3, "should match length of posts returned")
 	require.Equal(t, post4.Id, posts.Order[0], "should match returned post")
@@ -1622,7 +1666,7 @@ 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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 1, 3, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 1, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Posts, 1, "should match length of posts returned")
 	require.Equal(t, post5.Id, posts.Order[0], "should match returned post")
@@ -1638,7 +1682,7 @@ func TestGetPostsAfter(t *testing.T) {
 	post10 := th.CreatePost()
 
 	// similar to '/posts?after=post2'
-	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 60, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 60, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 8, "expected 8 posts")
 	require.Equal(t, post10.Id, posts.Order[0], "should match order")
@@ -1647,7 +1691,7 @@ 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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 3, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 0, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post5.Id, posts.Order[0], "should match order")
@@ -1656,7 +1700,7 @@ 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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 3, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 1, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 3, "expected 3 posts")
 	require.Equal(t, post8.Id, posts.Order[0], "should match order")
@@ -1665,7 +1709,7 @@ 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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 2, 3, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post2.Id, 2, 3, "", false, false)
 	require.NoError(t, err)
 	require.Len(t, posts.Order, 2, "expected 2 posts")
 	require.Equal(t, post10.Id, posts.Order[0], "should match order")
@@ -1674,14 +1718,14 @@ func TestGetPostsAfter(t *testing.T) {
 	require.Equal(t, post8.Id, posts.PrevPostId, "should return post8.Id as PrevPostId")
 
 	// similar to '/posts?after=post10'
-	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 0, 60, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 0, 60, "", false, false)
 	require.NoError(t, err)
 	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, _, err = client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 1, 60, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, post10.Id, 1, 60, "", false, false)
 	require.NoError(t, err)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
@@ -1689,11 +1733,33 @@ func TestGetPostsAfter(t *testing.T) {
 
 	// similar to '/posts?after=non-existent-post'
 	nonExistentPostId := model.NewId()
-	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false)
+	posts, _, err = client.GetPostsAfter(th.BasicChannel.Id, nonExistentPostId, 0, 60, "", false, false)
 	require.NoError(t, err)
 	require.Empty(t, posts.Order, "should return 0 post")
 	require.Equal(t, "", posts.NextPostId, "should return an empty NextPostId")
 	require.Equal(t, nonExistentPostId, posts.PrevPostId, "should return nonExistentPostId as PrevPostId")
+
+	client.DeletePost(post10.Id)
+	client.DeletePost(post9.Id)
+
+	// include deleted posts for non-admin users.
+	_, resp, err = client.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 60, "", false, true)
+	require.Error(t, err)
+	CheckForbiddenStatus(t, resp)
+
+	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
+		// include deleted posts for admin users.
+		posts, resp, err = c.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 60, "", false, true)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 9, "expected 9 posts")
+
+		// not include deleted posts for admin users.
+		posts, resp, err = c.GetPostsAfter(th.BasicChannel.Id, post1.Id, 0, 60, "", false, false)
+		require.NoError(t, err)
+		CheckOKStatus(t, resp)
+		require.Len(t, posts.Order, 7, "expected 7 posts")
+	})
 }
 
 func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
@@ -1798,7 +1864,7 @@ func TestGetPostsForChannelAroundLastUnread(t *testing.T) {
 	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, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false)
+	posts, _, err = client.GetPostsBefore(th.BasicChannel.Id, post1.Id, 0, 2, "", false, false)
 	require.NoError(t, err)
 	systemPost0 := posts.Posts[posts.Order[0]]
 	postIdNames[systemPost0.Id] = "system post 0"

api4/team_test.go

@@ -3028,7 +3028,7 @@ func TestImportTeam(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, importedChannel.Name, "general", "names did not match expected: general")
 
-		posts, _, err := th.SystemAdminClient.GetPostsForChannel(importedChannel.Id, 0, 60, "", false)
+		posts, _, err := th.SystemAdminClient.GetPostsForChannel(importedChannel.Id, 0, 60, "", false, false)
 		require.NoError(t, err)
 		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")
 	})

model/client4.go

@@ -3925,11 +3925,15 @@ func (c *Client4) GetPostThreadWithOpts(postID string, etag string, opts GetPost
 }
 
 // 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, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsForChannel(channelId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v", page, perPage)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err
@@ -4050,11 +4054,14 @@ func (c *Client4) GetPostsSince(channelId string, time int64, collapsedThreads b
 }
 
 // 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, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsAfter(channelId, postId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&after=%v", page, perPage, postId)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err
@@ -4071,11 +4078,14 @@ 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, collapsedThreads bool) (*PostList, *Response, error) {
+func (c *Client4) GetPostsBefore(channelId, postId string, page, perPage int, etag string, collapsedThreads bool, includeDeleted bool) (*PostList, *Response, error) {
 	query := fmt.Sprintf("?page=%v&per_page=%v&before=%v", page, perPage, postId)
 	if collapsedThreads {
 		query += "&collapsedThreads=true"
 	}
+	if includeDeleted {
+		query += "&include_deleted=true"
+	}
 	r, err := c.DoAPIGet(c.channelRoute(channelId)+"/posts"+query, etag)
 	if err != nil {
 		return nil, BuildResponse(r), err

model/permission.go

@@ -73,6 +73,7 @@ var PermissionDeleteOthersEmojis *Permission
 var PermissionCreatePost *Permission
 var PermissionCreatePostPublic *Permission
 var PermissionCreatePostEphemeral *Permission
+var PermissionReadDeletedPosts *Permission
 var PermissionEditPost *Permission
 var PermissionEditOthersPosts *Permission
 var PermissionDeletePost *Permission
@@ -708,6 +709,12 @@ func initializePermissions() {
 		"authentication.permissions.create_post_ephemeral.description",
 		PermissionScopeChannel,
 	}
+	PermissionReadDeletedPosts = &Permission{
+		"read_deleted_posts",
+		"authentication.permissions.read_deleted_posts.name",
+		"authentication.permissions.read_deleted_posts.description",
+		PermissionScopeChannel,
+	}
 	PermissionEditPost = &Permission{
 		"edit_post",
 		"authentication.permissions.edit_post.name",
@@ -2302,6 +2309,7 @@ func initializePermissions() {
 		PermissionCreatePost,
 		PermissionCreatePostPublic,
 		PermissionCreatePostEphemeral,
+		PermissionReadDeletedPosts,
 		PermissionEditPost,
 		PermissionEditOthersPosts,
 		PermissionDeletePost,

model/post.go

@@ -304,6 +304,7 @@ type GetPostsOptions struct {
 	FromPost                 string // PostId after which to send the items
 	FromCreateAt             int64  // CreateAt after which to send the items
 	Direction                string // Only accepts up|down. Indicates the order in which to send the items.
+	IncludeDeleted           bool
 }
 
 type PostCountOptions struct {

store/sqlstore/post_store.go

@@ -1168,13 +1168,13 @@ func (s *SqlPostStore) GetPosts(options model.GetPostsOptions, _ bool, sanitizeO
 
 	rpc := make(chan store.StoreResult, 1)
 	go func() {
-		posts, err := s.getRootPosts(options.ChannelId, offset, options.PerPage, options.SkipFetchThreads)
+		posts, err := s.getRootPosts(options.ChannelId, offset, options.PerPage, options.SkipFetchThreads, options.IncludeDeleted)
 		rpc <- store.StoreResult{Data: posts, NErr: err}
 		close(rpc)
 	}()
 	cpc := make(chan store.StoreResult, 1)
 	go func() {
-		posts, err := s.getParentsPosts(options.ChannelId, offset, options.PerPage, options.SkipFetchThreads)
+		posts, err := s.getParentsPosts(options.ChannelId, offset, options.PerPage, options.SkipFetchThreads, options.IncludeDeleted)
 		cpc <- store.StoreResult{Data: posts, NErr: err}
 		close(cpc)
 	}()
@@ -1440,13 +1440,18 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 		)
 	}
 	query := s.getQueryBuilder().Select(columns...)
-	replyCountSubQuery := s.getQueryBuilder().Select("COUNT(*)").From("Posts").Where(sq.Expr("Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0"))
+	replyCountSubQuery := s.getQueryBuilder().Select("COUNT(*)").From("Posts").Where(sq.Expr("Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END)"))
 
 	conditions := sq.And{
 		sq.Expr(`CreateAt `+direction+` (SELECT CreateAt FROM Posts WHERE Id = ?)`, options.PostId),
 		sq.Eq{"p.ChannelId": options.ChannelId},
-		sq.Eq{"p.DeleteAt": int(0)},
 	}
+
+	if !options.IncludeDeleted {
+		replyCountSubQuery = replyCountSubQuery.Where(sq.Expr("Posts.DeleteAt = 0"))
+		conditions = append(conditions, sq.Eq{"p.DeleteAt": int(0)})
+	}
+
 	if options.CollapsedThreads {
 		conditions = append(conditions, sq.Eq{"RootId": ""})
 		query = query.LeftJoin("Threads ON Threads.PostId = p.Id").LeftJoin("ThreadMemberships ON ThreadMemberships.PostId = p.Id AND ThreadMemberships.UserId=?", options.UserId)
@@ -1492,10 +1497,13 @@ func (s *SqlPostStore) getPostsAround(before bool, options model.GetPostsOptions
 			Where(sq.And{
 				idQuery,
 				sq.Eq{"p.ChannelId": options.ChannelId},
-				sq.Eq{"p.DeleteAt": 0},
 			}).
 			OrderBy("CreateAt DESC")
 
+		if !options.IncludeDeleted {
+			rootQuery = rootQuery.Where(sq.Eq{"p.DeleteAt": 0})
+		}
+
 		rootQueryString, rootArgs, nErr := rootQuery.ToSql()
 
 		if nErr != nil {
@@ -1620,14 +1628,21 @@ func (s *SqlPostStore) GetPostAfterTime(channelId string, time int64, collapsedT
 	return &post, nil
 }
 
-func (s *SqlPostStore) getRootPosts(channelId string, offset int, limit int, skipFetchThreads bool) ([]*model.Post, error) {
+func (s *SqlPostStore) getRootPosts(channelId string, offset int, limit int, skipFetchThreads bool, includeDeleted bool) ([]*model.Post, error) {
 	posts := []*model.Post{}
 	var fetchQuery string
 	if skipFetchThreads {
-		fetchQuery = "SELECT p.*, (SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) as ReplyCount FROM Posts p WHERE p.ChannelId = ? AND p.DeleteAt = 0 ORDER BY p.CreateAt DESC LIMIT ? OFFSET ?"
+		fetchQuery = "SELECT p.*, (SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END)) as ReplyCount FROM Posts p WHERE p.ChannelId = ? ORDER BY p.CreateAt DESC LIMIT ? OFFSET ?"
+		if !includeDeleted {
+			fetchQuery = "SELECT p.*, (SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) as ReplyCount FROM Posts p WHERE p.ChannelId = ? AND p.DeleteAt = 0 ORDER BY p.CreateAt DESC LIMIT ? OFFSET ?"
+		}
 	} else {
-		fetchQuery = "SELECT * FROM Posts WHERE Posts.ChannelId = ? AND Posts.DeleteAt = 0 ORDER BY Posts.CreateAt DESC LIMIT ? OFFSET ?"
+		fetchQuery = "SELECT * FROM Posts WHERE Posts.ChannelId = ? ORDER BY Posts.CreateAt DESC LIMIT ? OFFSET ?"
+		if !includeDeleted {
+			fetchQuery = "SELECT * FROM Posts WHERE Posts.ChannelId = ? AND Posts.DeleteAt = 0 ORDER BY Posts.CreateAt DESC LIMIT ? OFFSET ?"
+		}
 	}
+
 	err := s.GetReplicaX().Select(&posts, fetchQuery, channelId, limit, offset)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to find Posts")
@@ -1635,9 +1650,14 @@ func (s *SqlPostStore) getRootPosts(channelId string, offset int, limit int, ski
 	return posts, nil
 }
 
-func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int, skipFetchThreads bool) ([]*model.Post, error) {
+func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int, skipFetchThreads bool, includeDeleted bool) ([]*model.Post, error) {
 	if s.DriverName() == model.DatabaseDriverPostgres {
-		return s.getParentsPostsPostgreSQL(channelId, offset, limit, skipFetchThreads)
+		return s.getParentsPostsPostgreSQL(channelId, offset, limit, skipFetchThreads, includeDeleted)
+	}
+
+	deleteAtCondition := "AND DeleteAt = 0"
+	if includeDeleted {
+		deleteAtCondition = ""
 	}
 
 	// query parent Ids first
@@ -1651,9 +1671,8 @@ func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int,
 			FROM
 				Posts
 			WHERE
-				Posts.ChannelId = ?
+				ChannelId = ? ` + deleteAtCondition + ` 
-					AND Posts.DeleteAt = 0
+			ORDER BY CreateAt DESC
-			ORDER BY Posts.CreateAt DESC
 			LIMIT ? OFFSET ?) q
 		WHERE q.RootId != ''`
 
@@ -1669,7 +1688,11 @@ func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int,
 	var where sq.Sqlizer
 	where = sq.Eq{"p.Id": roots}
 	if skipFetchThreads {
-		cols = append(cols, "(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) as ReplyCount")
+		col := "(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END)) as ReplyCount"
+		if !includeDeleted {
+			col = "(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN p.RootId = '' THEN p.Id ELSE p.RootId END) AND Posts.DeleteAt = 0) as ReplyCount"
+		}
+		cols = append(cols, col)
 	} else {
 		where = sq.Or{
 			where,
@@ -1683,10 +1706,13 @@ func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int,
 		Where(sq.And{
 			where,
 			sq.Eq{"p.ChannelId": channelId},
-			sq.Eq{"p.DeleteAt": 0},
 		}).
 		OrderBy("p.CreateAt")
 
+	if !includeDeleted {
+		query = query.Where(sq.Eq{"p.DeleteAt": 0})
+	}
+
 	sql, args, err := query.ToSql()
 	if err != nil {
 		return nil, errors.Wrap(err, "ParentPosts_Tosql")
@@ -1700,15 +1726,25 @@ func (s *SqlPostStore) getParentsPosts(channelId string, offset int, limit int,
 	return posts, nil
 }
 
-func (s *SqlPostStore) getParentsPostsPostgreSQL(channelId string, offset int, limit int, skipFetchThreads bool) ([]*model.Post, error) {
+func (s *SqlPostStore) getParentsPostsPostgreSQL(channelId string, offset int, limit int, skipFetchThreads bool, includeDeleted bool) ([]*model.Post, error) {
 	posts := []*model.Post{}
 	replyCountQuery := ""
 	onStatement := "q1.RootId = q2.Id"
 	if skipFetchThreads {
-		replyCountQuery = ` ,(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN q2.RootId = '' THEN q2.Id ELSE q2.RootId END) AND Posts.DeleteAt = 0) as ReplyCount`
+		replyCountQuery = ` ,(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN q2.RootId = '' THEN q2.Id ELSE q2.RootId END)) as ReplyCount`
+		if !includeDeleted {
+			replyCountQuery = ` ,(SELECT COUNT(*) FROM Posts WHERE Posts.RootId = (CASE WHEN q2.RootId = '' THEN q2.Id ELSE q2.RootId END) AND Posts.DeleteAt = 0) as ReplyCount`
+		}
 	} else {
 		onStatement += " OR q1.RootId = q2.RootId"
 	}
+
+	deleteAtQueryCondition := "AND q2.DeleteAt = 0"
+	deleteAtSubQueryCondition := "AND Posts.DeleteAt = 0"
+	if includeDeleted {
+		deleteAtQueryCondition, deleteAtSubQueryCondition = "", ""
+	}
+
 	err := s.GetReplicaX().Select(&posts,
 		`SELECT q2.*`+replyCountQuery+`
         FROM
@@ -1722,15 +1758,13 @@ func (s *SqlPostStore) getParentsPostsPostgreSQL(channelId string, offset int, l
                 FROM
                     Posts
                 WHERE
-                    Posts.ChannelId = ?
+                    Posts.ChannelId = ? `+deleteAtSubQueryCondition+` 
-                        AND Posts.DeleteAt = 0
                 ORDER BY Posts.CreateAt DESC
                 LIMIT ? OFFSET ?) q3
             WHERE q3.RootId != '') q1
             ON `+onStatement+`
         WHERE
-            q2.ChannelId = ?
+            q2.ChannelId = ? `+deleteAtQueryCondition+` 
-            AND q2.DeleteAt = 0
         ORDER BY q2.CreateAt`, channelId, limit, offset, channelId)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to find Posts with channelId=%s", channelId)

store/storetest/post_store.go

@@ -1946,6 +1946,73 @@ func testPostStoreGetPosts(t *testing.T, ss store.Store) {
 		assert.Equal(t, int64(1), postList.Posts[post5.Id].ReplyCount)
 		assert.Equal(t, int64(1), postList.Posts[post6.Id].ReplyCount)
 	})
+
+	t.Run("should return all posts in a channel included deleted posts", func(t *testing.T) {
+		err := ss.Post().Delete(post1.Id, 1, userId)
+		require.NoError(t, err)
+
+		postList, err := ss.Post().GetPosts(model.GetPostsOptions{ChannelId: channelId, Page: 0, PerPage: 30, SkipFetchThreads: false, IncludeDeleted: true}, false, map[string]bool{})
+		require.NoError(t, err)
+
+		assert.Equal(t, []string{
+			post6.Id,
+			post5.Id,
+			post4.Id,
+			post3.Id,
+			post2.Id,
+			post1.Id,
+		}, postList.Order)
+
+		assert.Len(t, postList.Posts, 6)
+		assert.NotNil(t, postList.Posts[post1.Id])
+		assert.NotNil(t, postList.Posts[post2.Id])
+		assert.NotNil(t, postList.Posts[post3.Id])
+		assert.NotNil(t, postList.Posts[post4.Id])
+		assert.NotNil(t, postList.Posts[post5.Id])
+		assert.NotNil(t, postList.Posts[post6.Id])
+	})
+
+	t.Run("should return all posts in a channel included deleted posts without threads", func(t *testing.T) {
+		err := ss.Post().Delete(post5.Id, 1, userId)
+		require.NoError(t, err)
+
+		postList, err := ss.Post().GetPosts(model.GetPostsOptions{ChannelId: channelId, Page: 0, PerPage: 30, SkipFetchThreads: true, IncludeDeleted: true}, false, map[string]bool{})
+		require.NoError(t, err)
+
+		assert.Equal(t, []string{
+			post6.Id,
+			post5.Id,
+			post4.Id,
+			post3.Id,
+			post2.Id,
+			post1.Id,
+		}, postList.Order)
+
+		assert.Len(t, postList.Posts, 6)
+		assert.NotNil(t, postList.Posts[post5.Id])
+		assert.NotNil(t, postList.Posts[post6.Id])
+		assert.Equal(t, int64(1), postList.Posts[post5.Id].ReplyCount)
+		assert.Equal(t, int64(1), postList.Posts[post6.Id].ReplyCount)
+	})
+
+	t.Run("should return the lasts posts created in channel without include deleted posts", func(t *testing.T) {
+		err := ss.Post().Delete(post6.Id, 1, userId)
+		require.NoError(t, err)
+
+		postList, err := ss.Post().GetPosts(model.GetPostsOptions{ChannelId: channelId, Page: 0, PerPage: 30, SkipFetchThreads: true, IncludeDeleted: false}, false, map[string]bool{})
+		require.NoError(t, err)
+
+		assert.Equal(t, []string{
+			post4.Id,
+			post3.Id,
+			post2.Id,
+		}, postList.Order)
+
+		assert.Len(t, postList.Posts, 3)
+		assert.NotNil(t, postList.Posts[post2.Id])
+		assert.NotNil(t, postList.Posts[post3.Id])
+		assert.NotNil(t, postList.Posts[post4.Id])
+	})
 }
 
 func testPostStoreGetPostBeforeAfter(t *testing.T, ss store.Store) {