### Why?
Before, all flags were static. Therefore, they were stored in class variables and serialized by SiteSerializer. Recently, we added an option for admins to add their own flags or disable existing flags. Therefore, the class variable had to be dropped because it was unsafe for a multisite environment. However, it started causing performance problems.
### Solution
When a new Flag system is used, instead of using PostActionType, we can serialize Flags and use fragment cache for performance reasons.
At the same time, we are still supporting deprecated `replace_flags` API call. When it is used, we fall back to the old solution and the admin cannot add custom flags. In a couple of months, we will be able to drop that API function and clean that code properly. However, because it may still be used, redis cache was introduced to improve performance.
To test backward compatibility you can add this code to any plugin
```ruby
replace_flags do |flag_settings|
flag_settings.add(
4,
:inappropriate,
topic_type: true,
notify_type: true,
auto_action_type: true,
)
flag_settings.add(1001, :trolling, topic_type: true, notify_type: true, auto_action_type: true)
end
```
### Why?
Before, all flags were static. Therefore, they were stored in class variables and serialized by SiteSerializer. Recently, we added an option for admins to add their own flags or disable existing flags. Therefore, the class variable had to be dropped because it was unsafe for a multisite environment. However, it started causing performance problems.
### Solution
When a new Flag system is used, instead of using PostActionType, we can serialize Flags and use fragment cache for performance reasons.
At the same time, we are still supporting deprecated `replace_flags` API call. When it is used, we fall back to the old solution and the admin cannot add custom flags. In a couple of months, we will be able to drop that API function and clean that code properly. However, because it may still be used, redis cache was introduced to improve performance.
To test backward compatibility you can add this code to any plugin
```ruby
replace_flags do |flag_settings|
flag_settings.add(
4,
:inappropriate,
topic_type: true,
notify_type: true,
auto_action_type: true,
)
flag_settings.add(1001, :trolling, topic_type: true, notify_type: true, auto_action_type: true)
end
```
Admin can create up to 50 custom flags. It is limited for performance reasons.
When the limit is reached "Add button" is disabled and backend is protected by guardian.
Before migration is run flags code is evaluated. It is causing error:
```
NoMethodError: undefined method `require_message' for an instance of Flag (NoMethodError)
Did you mean? require_dependency
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activemodel-7.1.3.4/lib/active_model/attribute_methods.rb:489:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-7.1.3.4/lib/active_record/relation/delegation.rb💯in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-7.1.3.4/lib/active_record/relation/delegation.rb💯in `each'
/var/www/discourse/app/models/post_action_type.rb:64:in `reject'
```
The solution is to temporarily fall back to old column name - custom_type
Allow admin to create custom flag which requires an additional message.
I decided to rename the old `custom_flag` into `require_message` as it is more descriptive.
`after_commit` should be used before refreshing processes to be sure that the database is already updated.
Also, MessageBus is used instead of events as MessageBus works correctly with many processes;
Allow admin to create custom flag which requires an additional message.
I decided to rename the old `custom_flag` into `require_message` as it is more descriptive.
Continued work on moderate flags UI.
In this PR admins are allowed to change the order of flags. The notify user flag is always on top but all other flags can be moved.
