BUG: NullReferenceException when saving module settings on upgraded sites

[johnhenley]

Describe the bug

If you have an existing site that is upgraded to 8.0.x, you will get an exception when saving module settings. The exception doesn't really affect behavior unless you are using the module for a social group rather than standard forums.

Software Versions

• DNN: 09.12.00
• Module: 08.00.01

Version 8.0 added a new feature for banning users (PR #257), which required an additional security property "ModUser" to allow moderators to change users' settings (and ban them). This was added to security settings in the control panel (for standard forums) and module settings (for a social group forum) and to the configuration file used for new sites. The security settings are still stored as a module setting ("ForumConfig") -- even when the module is not used for a social group. However, for existing sites there were upgraded, the module setting was not updated. The result is that, when you switch the module settings from "standard" to "social group" on an upgraded site, you see a missing column on the right:

On a new install, it looks like this:

In addition, when the module settings are saved for an upgraded site, there is an exception in the admin log:

When run in the debugger, shows that this is caused by an incomplete list of security properties:

[Timo-Breumelhof]

@johnhenley good catch :-)

[johnhenley]

@WillStrohl wanted to get an opinion on this one. I've figured this out and have a code change ready. But as always, this uncovers a different but related issue. There are four settings (this being one) that are stored (intentionally, if you look at the code) into TabModuleSettings but because they are properties in the module settings, they end up getting stored in both TabModuleSettings and ModuleSettings. My intuition is to leave them in ModuleSettings and change to no longer store in TabModuleSettings. Since the module is not sharable on other pages/tabs, storing settings in TabModuleSettings really doesn't make any sense. What do you think?