Fix #previously_new_record? on destroyed records

[adrianna-chang-shopify]

Motivation / Background

Ref: #48794
cc @eizengan

Based on the documentation for #previously_new_record?:

Returns true if this object was just created – that is, prior to the last save, the object didn't exist in the database and new_record? would have returned true.

IMO a record that was previously created and has since been destroyed and removed from the database should no longer be considered "just created", although one could argue that a DELETE is different from a "save".

Detail

Set @previously_new_record to false in #destroy and #delete methods.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• Tests are added or updated if you fix a bug or add a feature.
• CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.

[eizengan]

IMO a record that was previously created and has since been destroyed and removed from the database should no longer be considered "just created", although one could argue that a DELETE is different from a "save".

My take as well.

prior to the last save, the object didn't exist in the database and new_record? would have returned true

feels less useful than e.g.

prior to the last call which permanently modified the object, the object didn't exist in the database and new_record? would have returned true

[nvasilevski]

Makes sense 👍

[eileencodes]

I thought about this for a bit and I'm kind of on the fence - it would depend whether we think a save and delete are different for this context. I think it is since a double save makes previously_new_record? return false. I think the docs should be updated though to reflect this change. Also with the slight change in behavior that might be surprising, can you add a CHANGELOG entry too?

[adrianna-chang-shopify]

it would depend whether we think a save and delete are different for this context.

Yeah, I was on the fence about this too. I ended up leaning towards these changes because the primary use case around #previously_new_record? seems to be for triggering callbacks on records that were newly created. Even though "save" and "delete" may be considered different in this context, we'd want to prevent a callback from firing off on the first "create" and then again on a destroy, as @eizengan demonstrated in the example in his issue.

I've updated the docs and added a CHANGELOG entry -- let me know what you think 😄