Delegated Type supports customizeable foreign_type column

[jasonkarns]

Adds support for customizing delegated_type's {role}_type column via the foreign_type option.

Summary

Delegated Types leans heavily on Rails’ existing polymorphic associations. The primary association created by delegated_type is a polymorphic belongs_to association.

For apps that are using polymorphic associations but need to customize the column containing the type/class, foreign_type is available as an option. It would be helpful if the same customization were available for Delegated Types.

Since delegated_types already passes its options along to the underlying belongs_to association, this is a relatively straightforward change. Instead of only deriving the type column by using "#{role}_type", it can respect a foreign_type option. (Same option key as used by polymorphic associations.)

Example:

delegated_type :entryable, types: %w[ Message Comment ], foreign_type: :entry_class

[skipkayhil]

Can you add a CHANGELOG entry in Active Record? The change makes sense to me

[jasonkarns]

@skipkayhil Added changelog entry and rebased. I assume the entry was supposed to go at the top. (I looked at its git-blame and most recent entries seemed to be at the top)

Happy to reword as desired.

[jasonkarns]

@skipkayhil rebased. any chance this can land in 7.1? Our team has an ugly monkey patch dealing with this right now.

[skipkayhil]

any chance this can land in 7.1?

It just needs to be reviewed by a committer. I'll see if I can get it some attention in the Discord

[eileencodes]

@jasonkarns can you add a test for this?

[jasonkarns]

@eileencodes tests added. I can squash/rebase again if necessary but wanted eyes on the tests before I do that. I'm not super familiar with the AR test suite opinions or patterns.

[eileencodes]

I left a couple comments about documentation/changelog. Otherwise this looks good. Let me know when you've rebased and squashed your commits. The changelog entry goes at the top of the file when fixing the conflict.

[jasonkarns]

@eileencodes rebased!