Follow threads without memberships if marked as unread (#17800)

app/user.go

@@ -2245,10 +2245,16 @@ func (a *App) UpdateThreadReadForUser(userID, teamID, threadID string, timestamp
 	if err != nil {
 		return nil, err
 	}
-	membership, nErr := a.Srv().Store.Thread().GetMembershipForUser(userID, threadID)
-	if nErr != nil {
-		return nil, model.NewAppError("UpdateThreadsReadForUser", "app.user.update_threads_read_for_user.app_error", nil, nErr.Error(), http.StatusInternalServerError)
+
+	opts := store.ThreadMembershipOpts{
+		Following:       true,
+		UpdateFollowing: false,
 	}
+	membership, storeErr := a.Srv().Store.Thread().MaintainMembership(userID, threadID, opts)
+	if storeErr != nil {
+		return nil, model.NewAppError("UpdateThreadReadForUser", "app.user.update_thread_read_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
 	post, err := a.GetSinglePost(threadID)
 	if err != nil {
 		return nil, err
@@ -2258,9 +2264,9 @@ func (a *App) UpdateThreadReadForUser(userID, teamID, threadID string, timestamp
 		return nil, err
 	}
 	membership.Following = true
-	_, nErr = a.Srv().Store.Thread().UpdateMembership(membership)
+	_, nErr := a.Srv().Store.Thread().UpdateMembership(membership)
 	if nErr != nil {
-		return nil, model.NewAppError("UpdateThreadsReadForUser", "app.user.update_threads_read_for_user.app_error", nil, nErr.Error(), http.StatusInternalServerError)
+		return nil, model.NewAppError("UpdateThreadReadForUser", "app.user.update_thread_read_for_user.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}
 
 	membership.LastViewed = timestamp

app/user_test.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"os"
 	"strings"
 	"testing"
 	"time"
@@ -1461,3 +1462,36 @@ func TestPatchUser(t *testing.T) {
 		require.Nil(t, err)
 	})
 }
+
+func TestUpdateThreadReadForUser(t *testing.T) {
+	os.Setenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS", "true")
+	defer os.Unsetenv("MM_FEATUREFLAGS_COLLAPSEDTHREADS")
+	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
+	})
+
+	t.Run("Ensure thread membership is created and followed", func(t *testing.T) {
+		rootPost, appErr := th.App.CreatePost(th.Context, &model.Post{UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
+		require.Nil(t, appErr)
+		replyPost, appErr := th.App.CreatePost(th.Context, &model.Post{RootId: rootPost.Id, UserId: th.BasicUser2.Id, CreateAt: model.GetMillis(), ChannelId: th.BasicChannel.Id, Message: "hi"}, th.BasicChannel, false, false)
+		require.Nil(t, appErr)
+		threads, appErr := th.App.GetThreadsForUser(th.BasicUser.Id, th.BasicTeam.Id, model.GetUserThreadsOpts{})
+		require.Nil(t, appErr)
+		require.Zero(t, threads.Total)
+
+		_, appErr = th.App.UpdateThreadReadForUser(th.BasicUser.Id, th.BasicChannel.TeamId, rootPost.Id, replyPost.CreateAt)
+		require.Nil(t, appErr)
+
+		threads, appErr = th.App.GetThreadsForUser(th.BasicUser.Id, th.BasicTeam.Id, model.GetUserThreadsOpts{})
+		require.Nil(t, appErr)
+		assert.NotZero(t, threads.Total)
+
+		threadMembership, appErr := th.App.GetThreadMembershipForUser(th.BasicUser.Id, rootPost.Id)
+		require.Nil(t, appErr)
+		require.NotNil(t, threadMembership)
+		assert.True(t, threadMembership.Following)
+	})
+}