Jürgen Kartnaller wrote:
I've also tried to create the subfolders in a subscriber on IObjectCreatedEvent, but this is equivalent to the previous attempt : NotYet error.

What I've understood is that the transaction that manages the folder is not finished, and the IntId utility is not yet able to get a connection on the ZODB. So I've tried to create an adapter to IConnection for my subfolder, so that it can use the same connection as the folder. But I couldn't. (however it might be possible?).

'NotYet' happens if the object in not connected to a database. The connection to the database exists as soon as your object is added to the object tree in zope. It is not related to a finished transaction.

That's not entirely true. The problem's origin is in zope.app.keyreference. In order to give newly created objects an integer id, the objects need to be adaptable to IKeyReference. The IKeyReference adapter for persistnet objects wants access to the object's database ("pickle jar").

Now, if the object has already been persisted before in an *already committed transaction*, it will have a _p_jar attribute. So, if the transaction were in fact finished, the IKeyReference adapter could take the object's _p_jar attribute right away.

But since the transaction isn't over yet and the object was just created, it has no _p_jar attribute, so the IKeyReference adapter does a bit of guessing. It walks up the __parent__ hierarchy and figures that if the newly created object is part of a container somewhere, it will be persisted in the same database. So it takes the container's _p_jar. This is the reason why IKeyReference wants an intact __parent__ hierarchy for newly created objects.

The simple solution is to create the subfolders AFTER the folder has been eventually ADDED with the add method. So in the AddForm, I've replaced the create() method with a createAndAdd method. In this method, I've just created my folder, called add to add it, then only I could create the subfolders and add them to the folder.

You can also do this using an event handler for ObjectAddedEvent on your Folder. In this case you do not need to touch any code in your form.

Yes, this is what I'd recommend. A handler for an ObjectAddedEvent will always see the object already as part of the object hierarchy (which is, after all, what ObjectAddedEvent is about).

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