fix no-cloud-limit error (#21447)

app/post.go

@@ -1440,6 +1440,11 @@ func (a *App) ComputeLastAccessiblePostTime() error {
 		return appErr
 	}
 
+	if limit == 0 {
+		// Cloud limit is not applicable
+		return nil
+	}
+
 	createdAt, err := a.Srv().GetStore().Post().GetNthRecentPostTime(limit)
 	if err != nil {
 		var nfErr *store.ErrNotFound

app/post_test.go

@@ -2857,6 +2857,7 @@ func TestGetLastAccessiblePostTime(t *testing.T) {
 }
 
 func TestComputeLastAccessiblePostTime(t *testing.T) {
+	t.Run("Updates the time, if cloud limit is applicable", func(t *testing.T) {
 		th := SetupWithStoreMock(t)
 		defer th.TearDown()
 
@@ -2865,6 +2866,7 @@ func TestComputeLastAccessiblePostTime(t *testing.T) {
 		cloud := &eMocks.CloudInterface{}
 		th.App.Srv().Cloud = cloud
 
+		// cloud-starter, limit is applicable
 		cloud.Mock.On("GetCloudLimits", mock.Anything).Return(&model.ProductLimits{
 			Messages: &model.MessagesLimits{
 				History: model.NewInt(1),
@@ -2883,6 +2885,30 @@ func TestComputeLastAccessiblePostTime(t *testing.T) {
 		assert.NoError(t, err)
 
 		mockSystemStore.AssertCalled(t, "SaveOrUpdate", mock.Anything)
+	})
+
+	t.Run("Do NOT update the time, if cloud limit is NOT applicable", func(t *testing.T) {
+		th := SetupWithStoreMock(t)
+		defer th.TearDown()
+
+		th.App.Srv().SetLicense(model.NewTestLicense("cloud"))
+
+		cloud := &eMocks.CloudInterface{}
+		th.App.Srv().Cloud = cloud
+
+		// enterprise, limit is NOT applicable
+		cloud.Mock.On("GetCloudLimits", mock.Anything).Return(nil, nil)
+
+		mockStore := th.App.Srv().Store().(*storemocks.Store)
+		mockSystemStore := storemocks.SystemStore{}
+		mockSystemStore.On("SaveOrUpdate", mock.Anything).Return(nil)
+		mockStore.On("System").Return(&mockSystemStore)
+
+		err := th.App.ComputeLastAccessiblePostTime()
+		assert.NoError(t, err)
+
+		mockSystemStore.AssertNotCalled(t, "SaveOrUpdate", mock.Anything)
+	})
 }
 
 func TestGetTopThreadsForTeamSince(t *testing.T) {