Utilise $owns for recursive duplication

[pitchandtone]

Since $owns handles versioning cascade, and should handle unpublish, we should also be able to imply duplication (similar to publish). The logic should be similar to the recursive publish method.

Acceptance Criterea:

• Any duplicated object will include all owned objects (or duplicates as necessary) from the original
• Developers can customise the list of objects that are duplicated automatically
• Documentation describes how this works
• Tests cover any new features

PRs

• API Implement cascade_duplications silverstripe-framework#7819
• API Ensure that duplications fail over to owned objects #106

[pitchandtone]

I have supplied an example of how we've handled this on Elemental here: #25 (comment)

[pitchandtone]

@sminnee, @chillu, @tractorcow have also made similar comments here:
#23 (comment)
#23 (comment)
#23 (comment)

[tractorcow]

At the moment we have the following method signature for duplicate:

public function duplicate($doWrite = true, $manyMany = 'many_many')

What we could do is change it to

public function duplicate($doWrite = true, $withOwned = true)

So that it allows you to duplicate owned objects, rather than trying to infer it from the relationship type.

Note that many_many currently only duplicates the mapping table.

We could use the following behaviour:

• $withOwned = true, duplicates owned many_many mapping table, duplicate actual object for has_one and has_many.
• $withOwned = false, duplicate only this object and not related.

@pitchandtone would love to hear your feelings. :)

[pitchandtone]

@tractorcow wouldn't matching the publish api signature be better? duplicateRecursive and duplicateSingle? and then deprecating duplicate for v5, but calling Recursive if $withOwned = true

[sminnee]

+1 for API consistency.

[chillu]

The ticket title reads "Utilise $owns for recursive duplication and deletion", but the comments only discuss duplication. On #23 the consensus seems to be that we can't infer delete/unpublish from ownership. Should we limit this ticket to duplication?

[tractorcow]

Renamed.

[tractorcow]

@tractorcow wouldn't matching the publish api signature be better? duplicateRecursive and duplicateSingle? and then deprecating duplicate for v5, but calling Recursive if $withOwned = true

This is fine, since duplicate() is dataobject, but duplicateRecursive() / duplicateSingle() can be versioned specific.

This will make it opt-in though.

[sminnee]

My view is:

• Publication & duplication: inferred from owns
• Deletion & unpublishing: inferred from cascade_deletes

"Owns" kind of means "cascade_creates"

Make sense?

[tractorcow]

Yes I think so.

You agree that with owned many_many, we should only need to duplicate the mapping though, correct?

[chillu]

Moving this to impact/high so it stays on our radar, since it's a co-fund commitment.

[tractorcow]

WIP branches:

• https://github.com/open-sausages/silverstripe-framework/tree/pulls/4/duplicates-is-easy
• https://github.com/open-sausages/silverstripe-versioned/tree/pulls/1/duplicates-is-easy

I'm going to have a cascade_duplications that will let you override owns so you have a degree of control.

[flamerohr]

API has been merged, recursive duplication is now available