[Zope-dev] zope.xmlpickle

[Michael Dunstan]

Hi all,

I have been trying out ``zope.xmlpickle`` as a alternative to
XMLExportImport in Zope2. Seems to do the job just fine. Grab Zope
2.9.3 and install zope.xmlpickle by hand using something of the form:

  % cd /opt/Zope-2.9/lib/python/zope
  % svn checkout svn://svn.zope.org/repos/main/Zope3/trunk/src/zope/xmlpickle

Then using zopectl debug:

  >>> from zope.xmlpickle import dumps

Picking on something simple to start with:

  >>> xml = dumps(app.acl_users.aq_base)
  >>> print xml
  <?xml version="1.0" encoding="utf-8" ?>
  <pickle>
    <initialized_object>
      <klass>
        <global name="__newobj__" module="copy_reg"/>
      </klass>
      <arguments>
        <tuple>
          <global name="SiteErrorLog"
module="Products.SiteErrorLog.SiteErrorLog"/>
        </tuple>
      </arguments>
      <state>
        <dictionary>
          <item key="_ignored_exceptions">
              <tuple>
                <string>Unauthorized</string>
                <string>Redirect</string>
                <string>NotFound</string>
              </tuple>
          </item>
          <item key="copy_to_zlog">
              <true/>
          </item>
          <item key="keep_entries">
              <int>20</int>
          </item>
        </dictionary>
      </state>
    </initialized_object>
  </pickle>


That looks okay. But I strike problems with ``Missing.Value`` when
trying this on something that includes a catalog. The simplest way
to recreate the problem::

  >>> import Missing
  >>> dumps(Missing.Value())
  Traceback (most recent call last):
    File "<stdin>", line 1, in ?
    File "/opt/Zope-2.9/lib/python/zope/xmlpickle/xmlpickle.py", line
146, in dumps
      p = _dumpsUsing_PicklerThatSortsDictItems(ob, 1)
    File "/opt/Zope-2.9/lib/python/zope/xmlpickle/xmlpickle.py", line
73, in _dumpsUsing_PicklerThatSortsDictItems
      _PicklerThatSortsDictItems(file, bin).dump(object)
    File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/pickle.py",
line 231, in dump
      self.save(obj)
    File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/pickle.py",
line 324, in save
      self.save_global(obj, rv)
    File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/pickle.py",
line 753, in save_global
      module = whichmodule(obj, name)
    File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/pickle.py",
line 825, in whichmodule
      if func in classmap:
  TypeError: unhashable type

Meanwhile, dumps seems to work quite happy with many other examples
that I tried. Including all the content of a plone site minus a couple
of the catalogs. And ``zope.xmlpickle.loads`` seems to do the right thing too.

Any suggestions on getting a successful dumps of a Missing.Value?


Cheers
Michael