We were getting an exception in this case, which was OK I guess since
this shouldn't happen if the application is used in a normal way, but we
can simplify the code a little bit if we make the `recipients` code
return an empty list of users.
Note that the behavior of the `AdminNotification#list_of_recipients` and
`Newsletter#list_of_recipient_emails` methods is now slightly different;
previously they returned `nil` when given an invalid segment recipient,
while now they return an empty array. I haven't found a place where this
change is relevant. For example, in both of these models, the `deliver`
method used to raise an exception when given an invalid segment while
now it doesn't, but we always check the user segment is valid before
calling the `deliver` method anyway, so it doesn't really affect the
application.
We were getting a warning by CodeQL regarding a possible code injection
in the `send(segment)` code.
In practice, this wasn't a big deal because the `self.recipients` method
is only called in the admin section, meaning only admin users could try
to take advantage of the code injection, and because this code is rarely
called with an invalid segment due to several conditions in the code
checking that the user segment is valid, with the only exception being
the `generate_csv` action in the `Admin::EmailsDownloadController`.
In any case, now we're checking that the segment is valid before calling
the `send` method. Since now we're making sure that the segment is valid
in the `recipients` method itself, we can remove this check from methods
calling it.
The purpose of the lib folder is to have code that doesn't necessary
belong in the application but can be shared with other applications.
However, we don't have other applications and, if we did, the way to
share code between them would be using a gem or even a git submodule.
So having both the `app/` and the `lib/` folders is confusing IMHO, and
it causes unnecessary problems with autoloading.
So we're moving the `lib/` folder to `app/lib/`. Originally, some of
these files were in the `app/services/` folder and then they were moved
to the `lib/` folder. We're using `app/lib/` instead of `app/services/`
so the upgrade is less confusing.
There's an exception, though. The `OmniAuth::Strategies::Wordpress`
class needs to be available in the Devise initializer. Since this is an
initializer and trying to autoload a class here will be problematic when
switching to Zeitwerk, we'll keep the `require` clause on top of the
Devise initializer in order to load the file and so it will be loaded
even if it isn't in the autoload paths anymore.
