Remove Struct inheritance from headless policy example

[drewmoore]

This addresses #696. Rubocop advises against inheriting from Struct, and my team found that we could simply remove this and achieve the same results. Thanks for your review.

[dgmstuart]

I'm not sure this is enough: to me this suggests that just defining an empty class with a Policy suffix is enough, while in reality we need a very specific initialiser and accessors to be defined.

How would you feel about explicitly writing out the initialiser and accessors as part of this documentation?

Presumably the motivation behind using Struct was as a shorthand for that (but I do see why it doesn't work).

Alternatively maybe it's worth making a HeadlessPolicy class to help avoid this repeated boilerplate 🤷

[Burgestrand]

Another option is to use the other Struct approach, which Rubocop is OK with?

DashboardPolicy = Struct.new(:user, :dashboard) do
  # ...
end

[drewmoore]

True, I might also have come to that conclusion. Would this help to clarify? d17ca6c. As far as having an inherited class for headless policies, we actually just inherit from the same base policy class that all of our other policies use. The only difference is that the 2nd parameter of the initializer will just be the symbol passed to authorize, in this case :dashboard. Our working implementation is actually quite minimal.

[Burgestrand]

The _record is :dashboard, which is still the second argument :)

[drewmoore]

I believe the first argument provided to authorize in this case would be :dashboard, whereas the second parameter in the policy's initializer method would in this case be :dashboard.

[Burgestrand]

Yup! The passage does talk about the headless policy, though?

Note that the headless policy still needs to accept two arguments. The
second argument will just be the symbol :dashboard in this case which […]

[dgmstuart]

Is this an attempt to fix an unrelated issue?

In this case the authorize method accepts only one argument, while the policy initializer accepts two. This line is pretty clearly talking about the policy initializer since the line before says:

Note that the headless policy still needs to accept two arguments.

Maybe this area of the documentation could be clarified, but that feels completely independent of the change to remove Struct.

[drewmoore]

Changed: 67e0dd3

[Burgestrand]

Thank you!