[Zope-dev] Creating and pasting to a ZClass within a single transaction does not work

[Jim Fulton]

Kevin Dangoor wrote:
> 
> Hi,
> 
>     Last week, there was an exchange going on because I was having trouble
> copying and pasting in DTML (or Python) from a Folder to a ZClass instance.
> The thread started with
> http://www.zope.org/pipermail/zope-dev/1999-August/001248.html
> 
>     It looks like the problem is that I was creating the ZClass instance and
> doing the copy/paste operation all at once. If I use one DTML method to
> create the new objects, and then a second method to do the copy/paste,
> everything works just fine.
> 
>     Should there be a problem pasting objects to a new object within the
> same transaction?

The problem is that manage_pasteObjects needs to be called on
an object that is already in the database.  A new object doesn't
actually get inserted into the database until the transaction commits.
The new object needs to have a _p_jar attribute (a database connection)
that is not None, which it can then use to reconstitute the source object
from the moniker.  You cold get around this with sub-transactions, 
but there is an easier way. 

Rather than going through monikers, it would easier to use manage_clone 
which copies and pastes objects directly.

I think you want something like:

  def candp(fobj, tobj, REQUEST):
    "Copy and paste"

    for id in fobj.objectIds():
       tobj.manage_clone(getattr(fobj,id),id,REQUEST)

Note that you need pass REQUEST for security purposes, 
since manage_clone tries to make sure that you are allowed
to add the objects to the destination.

Jim

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